[SERVER-18905] Server should reject array values for sort specification Created: 10/Jun/15  Updated: 06/Dec/22  Resolved: 02/Jun/17

Status: Closed
Project: Core Server
Component/s: Querying
Affects Version/s: 3.0.3
Fix Version/s: None

Type: Improvement Priority: Major - P3
Reporter: Patrick Lauber Assignee: Backlog - Query Team (Inactive)
Resolution: Won't Fix Votes: 0
Labels: neweng
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Duplicate
is duplicated by SERVER-19294 $orderby meta operator allows an arra... Closed
Related
is related to DOCS-5598 Document passing array to $orderby/.s... Closed
Assigned Teams:
Query
Participants:

 Description   

Passing invalid syntax to sort() should trigger an error. For example

find().sort([('_id', -1)])

may return different results than

find().sort({_id : 1})

which can cause confusion.

Original description

I have a sharded cluster and the following queries give me different results:

db.all_events.aggregate([{$match:{'session_id':'1389946222338', 'event_type': {'$in': PREV_EVENTS}, 'timestamp': {'$lte': ISODate("2014-01-17T08:16:49.963Z")}, _id:{$ne:ObjectId('555b4b1c6d5ba860366c78e2')}}}, {$sort:{timestamp:-1, _id:-1}}, {$limit:1}])

db.all_events.find({'session_id':'1389946222338', 'event_type': {'$in': PREV_EVENTS}, 'timestamp': {'$lte': ISODate("2014-01-17T08:16:49.963Z")}, '_id': {'$ne': ObjectId('555b4b1c6d5ba860366c78e2')}}).sort([('timestamp', -1), ('_id', -1)]).limit(1)

Only the aggregate gives the correct result. That something like this can happen is BAD.



 Comments   
Comment by David Storch [ 02/Jun/17 ]

Version 3.2.0 introduced the find command, a new protocol for expressing find operations. The find command does not support sorts specified as arrays. This behavior is unique to legacy OP_QUERY find. Rather than explicitly removing support for it, we should remove support as part of deprecating/removing OP_QUERY find entirely. Closing as Won't Fix.

Comment by J Rassi [ 16/Jun/15 ]

Note that there is actually no syntax in Javascript which supports constructing objects with an array of key-value tuples, as in [(key, value)]. The expression (key, value) in Javascript evaluates to value, as the comma operator returns the value of the last operand. Hence, the operation find().sort([('_id', -1)]) is first evaluated to find().sort([-1]), and then generates a query message that is sent off to the server. The server doesn't recognize a sort specification of [-1], and (unhelpfully) ignores it.

However, some versions of the server have supported array-based sort specifications where the array contains a list of objects describing key/value pairs, e.g. [{a: 1}, {b: 1}]. However, this syntax has never been documented. I investigated this feature's history, and discovered that it was introduced in an early version of the server, but was unintentionally broken in version 1.3.3 by 62aad0ee, and then was unintentionally fixed in version 2.5.3. After discussion with david.storch, we've decided to remove support for this syntax entirely, considering that the feature has been broken for many years and has never been documented.

I've updated the ticket summary accordingly.

Comment by Ramon Fernandez Marina [ 10/Jun/15 ]

Thanks for the additional information digi604. I agree that it would be helpful if sort() at least warned about not using the argument for sorting, so I'm going to re-purpose this ticket as an improvement request.

Cheers,
Ramón.

Comment by Patrick Lauber [ 10/Jun/15 ]

so... there really should be an error message if you try something like:

sort([('timestamp', -1), ('_id', -1)])

Comment by Patrick Lauber [ 10/Jun/15 ]

output is now the same

Comment by Patrick Lauber [ 10/Jun/15 ]

if i change the 2nd query to an object instead of an array:

db.all_events.find({'session_id':'1389946222338', 'event_type': {'$in': PREV_EVENTS}, 'timestamp': {'$lte': ISODate("2014-01-17T08:16:49.963Z")}, '_id': {'$ne': ObjectId('555b4b1c6d5ba860366c78e2')}}).sort({'timestamp':-1, '_id': -1}).limit(1).explain(true)
{
	"queryPlanner" : {
		"mongosPlannerVersion" : 1,
		"winningPlan" : {
			"stage" : "SHARD_MERGE_SORT",
			"shards" : [
				{
					"shardName" : "eventsdata_0",
					"connectionString" : "eventsdata_0/events-cluster-20.pitcher.9790.mongodbdns.com:27000,events-cluster-21.pitcher.9790.mongodbdns.com:27000",
					"serverInfo" : {
						"host" : "events-cluster-20",
						"port" : 27000,
						"version" : "3.0.3",
						"gitVersion" : "b40106b36eecd1b4407eb1ad1af6bc60593c6105"
					},
					"plannerVersion" : 1,
					"namespace" : "events.all_events",
					"indexFilterSet" : false,
					"parsedQuery" : {
						"$and" : [
							{
								"$not" : {
									"_id" : {
										"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
									}
								}
							},
							{
								"timestamp" : {
									"$lte" : ISODate("2014-01-17T08:16:49.963Z")
								}
							},
							{
								"session_id" : {
									"$eq" : "1389946222338"
								}
							},
							{
								"event_type" : {
									"$in" : [
										"changePDFPage",
										"closeMovie",
										"closePDF",
										"closePresentation",
										"closePresentationForJumping",
										"deactivate",
										"endDetail",
										"exitApp",
										"lms_interaction",
										"loadMovie",
										"loadPDF",
										"loadPresentation",
										"loadWebPageFromFolder",
										"quiz_result",
										"scroll",
										"set_score",
										"surveyComplete"
									]
								}
							}
						]
					},
					"winningPlan" : {
						"stage" : "SORT",
						"sortPattern" : {
							"timestamp" : -1,
							"_id" : -1
						},
						"limitAmount" : 1,
						"inputStage" : {
							"stage" : "FETCH",
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "IXSCAN",
									"keyPattern" : {
										"session_id" : 1,
										"event_type" : 1,
										"timestamp" : -1,
										"_id" : -1
									},
									"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
									"isMultiKey" : false,
									"direction" : "forward",
									"indexBounds" : {
										"session_id" : [
											"[\"1389946222338\", \"1389946222338\"]"
										],
										"event_type" : [
											"[\"changePDFPage\", \"changePDFPage\"]",
											"[\"closeMovie\", \"closeMovie\"]",
											"[\"closePDF\", \"closePDF\"]",
											"[\"closePresentation\", \"closePresentation\"]",
											"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
											"[\"deactivate\", \"deactivate\"]",
											"[\"endDetail\", \"endDetail\"]",
											"[\"exitApp\", \"exitApp\"]",
											"[\"lms_interaction\", \"lms_interaction\"]",
											"[\"loadMovie\", \"loadMovie\"]",
											"[\"loadPDF\", \"loadPDF\"]",
											"[\"loadPresentation\", \"loadPresentation\"]",
											"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
											"[\"quiz_result\", \"quiz_result\"]",
											"[\"scroll\", \"scroll\"]",
											"[\"set_score\", \"set_score\"]",
											"[\"surveyComplete\", \"surveyComplete\"]"
										],
										"timestamp" : [
											"[new Date(1389946609963), true)"
										],
										"_id" : [
											"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
											"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
										]
									}
								}
							}
						}
					},
					"rejectedPlans" : [
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"event_type" : 1
										},
										"indexName" : "event_type_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"session_id" : -1
										},
										"indexName" : "session_id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"session_id" : 1
										},
										"indexName" : "session_id_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"timestamp" : -1
										},
										"indexName" : "timestamp_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"timestamp" : [
												"[new Date(1389946609963), true)"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"_id" : 1
										},
										"indexName" : "_id_",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"_id" : [
												"[MinKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MaxKey]"
											]
										}
									}
								}
							}
						}
					]
				},
				{
					"shardName" : "eventsdata_1",
					"connectionString" : "eventsdata_1/events-cluster-22.pitcher.9790.mongodbdns.com:27000,events-cluster-25.pitcher.9790.mongodbdns.com:27000",
					"serverInfo" : {
						"host" : "events-cluster-22",
						"port" : 27000,
						"version" : "3.0.3",
						"gitVersion" : "b40106b36eecd1b4407eb1ad1af6bc60593c6105"
					},
					"plannerVersion" : 1,
					"namespace" : "events.all_events",
					"indexFilterSet" : false,
					"parsedQuery" : {
						"$and" : [
							{
								"$not" : {
									"_id" : {
										"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
									}
								}
							},
							{
								"timestamp" : {
									"$lte" : ISODate("2014-01-17T08:16:49.963Z")
								}
							},
							{
								"session_id" : {
									"$eq" : "1389946222338"
								}
							},
							{
								"event_type" : {
									"$in" : [
										"changePDFPage",
										"closeMovie",
										"closePDF",
										"closePresentation",
										"closePresentationForJumping",
										"deactivate",
										"endDetail",
										"exitApp",
										"lms_interaction",
										"loadMovie",
										"loadPDF",
										"loadPresentation",
										"loadWebPageFromFolder",
										"quiz_result",
										"scroll",
										"set_score",
										"surveyComplete"
									]
								}
							}
						]
					},
					"winningPlan" : {
						"stage" : "SORT",
						"sortPattern" : {
							"timestamp" : -1,
							"_id" : -1
						},
						"limitAmount" : 1,
						"inputStage" : {
							"stage" : "FETCH",
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "IXSCAN",
									"keyPattern" : {
										"session_id" : 1,
										"event_type" : 1,
										"timestamp" : -1,
										"_id" : -1
									},
									"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
									"isMultiKey" : false,
									"direction" : "forward",
									"indexBounds" : {
										"session_id" : [
											"[\"1389946222338\", \"1389946222338\"]"
										],
										"event_type" : [
											"[\"changePDFPage\", \"changePDFPage\"]",
											"[\"closeMovie\", \"closeMovie\"]",
											"[\"closePDF\", \"closePDF\"]",
											"[\"closePresentation\", \"closePresentation\"]",
											"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
											"[\"deactivate\", \"deactivate\"]",
											"[\"endDetail\", \"endDetail\"]",
											"[\"exitApp\", \"exitApp\"]",
											"[\"lms_interaction\", \"lms_interaction\"]",
											"[\"loadMovie\", \"loadMovie\"]",
											"[\"loadPDF\", \"loadPDF\"]",
											"[\"loadPresentation\", \"loadPresentation\"]",
											"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
											"[\"quiz_result\", \"quiz_result\"]",
											"[\"scroll\", \"scroll\"]",
											"[\"set_score\", \"set_score\"]",
											"[\"surveyComplete\", \"surveyComplete\"]"
										],
										"timestamp" : [
											"[new Date(1389946609963), true)"
										],
										"_id" : [
											"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
											"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
										]
									}
								}
							}
						}
					},
					"rejectedPlans" : [
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"event_type" : 1
										},
										"indexName" : "event_type_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"session_id" : -1
										},
										"indexName" : "session_id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"session_id" : 1
										},
										"indexName" : "session_id_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"timestamp" : -1
										},
										"indexName" : "timestamp_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"timestamp" : [
												"[new Date(1389946609963), true)"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"_id" : 1
										},
										"indexName" : "_id_",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"_id" : [
												"[MinKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MaxKey]"
											]
										}
									}
								}
							}
						}
					]
				},
				{
					"shardName" : "eventsdata_2",
					"connectionString" : "eventsdata_2/events-cluster-23.pitcher.9790.mongodbdns.com:27000,events-cluster-24.pitcher.9790.mongodbdns.com:27000",
					"serverInfo" : {
						"host" : "events-cluster-23",
						"port" : 27000,
						"version" : "3.0.3",
						"gitVersion" : "b40106b36eecd1b4407eb1ad1af6bc60593c6105"
					},
					"plannerVersion" : 1,
					"namespace" : "events.all_events",
					"indexFilterSet" : false,
					"parsedQuery" : {
						"$and" : [
							{
								"$not" : {
									"_id" : {
										"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
									}
								}
							},
							{
								"timestamp" : {
									"$lte" : ISODate("2014-01-17T08:16:49.963Z")
								}
							},
							{
								"session_id" : {
									"$eq" : "1389946222338"
								}
							},
							{
								"event_type" : {
									"$in" : [
										"changePDFPage",
										"closeMovie",
										"closePDF",
										"closePresentation",
										"closePresentationForJumping",
										"deactivate",
										"endDetail",
										"exitApp",
										"lms_interaction",
										"loadMovie",
										"loadPDF",
										"loadPresentation",
										"loadWebPageFromFolder",
										"quiz_result",
										"scroll",
										"set_score",
										"surveyComplete"
									]
								}
							}
						]
					},
					"winningPlan" : {
						"stage" : "SORT",
						"sortPattern" : {
							"timestamp" : -1,
							"_id" : -1
						},
						"limitAmount" : 1,
						"inputStage" : {
							"stage" : "FETCH",
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "IXSCAN",
									"keyPattern" : {
										"session_id" : 1,
										"event_type" : 1,
										"timestamp" : -1,
										"_id" : -1
									},
									"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
									"isMultiKey" : false,
									"direction" : "forward",
									"indexBounds" : {
										"session_id" : [
											"[\"1389946222338\", \"1389946222338\"]"
										],
										"event_type" : [
											"[\"changePDFPage\", \"changePDFPage\"]",
											"[\"closeMovie\", \"closeMovie\"]",
											"[\"closePDF\", \"closePDF\"]",
											"[\"closePresentation\", \"closePresentation\"]",
											"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
											"[\"deactivate\", \"deactivate\"]",
											"[\"endDetail\", \"endDetail\"]",
											"[\"exitApp\", \"exitApp\"]",
											"[\"lms_interaction\", \"lms_interaction\"]",
											"[\"loadMovie\", \"loadMovie\"]",
											"[\"loadPDF\", \"loadPDF\"]",
											"[\"loadPresentation\", \"loadPresentation\"]",
											"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
											"[\"quiz_result\", \"quiz_result\"]",
											"[\"scroll\", \"scroll\"]",
											"[\"set_score\", \"set_score\"]",
											"[\"surveyComplete\", \"surveyComplete\"]"
										],
										"timestamp" : [
											"[new Date(1389946609963), true)"
										],
										"_id" : [
											"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
											"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
										]
									}
								}
							}
						}
					},
					"rejectedPlans" : [
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"event_type" : 1
										},
										"indexName" : "event_type_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"session_id" : -1
										},
										"indexName" : "session_id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"session_id" : 1
										},
										"indexName" : "session_id_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"timestamp" : -1
										},
										"indexName" : "timestamp_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"timestamp" : [
												"[new Date(1389946609963), true)"
											]
										}
									}
								}
							}
						},
						{
							"stage" : "SORT",
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"_id" : 1
										},
										"indexName" : "_id_",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"_id" : [
												"[MinKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MaxKey]"
											]
										}
									}
								}
							}
						}
					]
				}
			]
		}
	},
	"executionStats" : {
		"nReturned" : 3,
		"executionTimeMillis" : 4,
		"totalKeysExamined" : 43,
		"totalDocsExamined" : 30,
		"executionStages" : {
			"stage" : "SHARD_MERGE_SORT",
			"nReturned" : 3,
			"executionTimeMillis" : 4,
			"totalKeysExamined" : 43,
			"totalDocsExamined" : 30,
			"totalChildMillis" : NumberLong(3),
			"shards" : [
				{
					"shardName" : "eventsdata_0",
					"executionSuccess" : true,
					"executionStages" : {
						"stage" : "SORT",
						"nReturned" : 1,
						"executionTimeMillisEstimate" : 0,
						"works" : 18,
						"advanced" : 1,
						"needTime" : 15,
						"needFetch" : 0,
						"saveState" : 0,
						"restoreState" : 0,
						"isEOF" : 1,
						"invalidates" : 0,
						"sortPattern" : {
							"timestamp" : -1,
							"_id" : -1
						},
						"memUsage" : 1015,
						"memLimit" : 33554432,
						"limitAmount" : 1,
						"inputStage" : {
							"stage" : "FETCH",
							"nReturned" : 10,
							"executionTimeMillisEstimate" : 0,
							"works" : 15,
							"advanced" : 10,
							"needTime" : 4,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 1,
							"invalidates" : 0,
							"docsExamined" : 10,
							"alreadyHasObj" : 0,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 10,
								"executionTimeMillisEstimate" : 0,
								"works" : 15,
								"advanced" : 10,
								"needTime" : 4,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 1,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "IXSCAN",
									"nReturned" : 10,
									"executionTimeMillisEstimate" : 0,
									"works" : 15,
									"advanced" : 10,
									"needTime" : 4,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 1,
									"invalidates" : 0,
									"keyPattern" : {
										"session_id" : 1,
										"event_type" : 1,
										"timestamp" : -1,
										"_id" : -1
									},
									"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
									"isMultiKey" : false,
									"direction" : "forward",
									"indexBounds" : {
										"session_id" : [
											"[\"1389946222338\", \"1389946222338\"]"
										],
										"event_type" : [
											"[\"changePDFPage\", \"changePDFPage\"]",
											"[\"closeMovie\", \"closeMovie\"]",
											"[\"closePDF\", \"closePDF\"]",
											"[\"closePresentation\", \"closePresentation\"]",
											"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
											"[\"deactivate\", \"deactivate\"]",
											"[\"endDetail\", \"endDetail\"]",
											"[\"exitApp\", \"exitApp\"]",
											"[\"lms_interaction\", \"lms_interaction\"]",
											"[\"loadMovie\", \"loadMovie\"]",
											"[\"loadPDF\", \"loadPDF\"]",
											"[\"loadPresentation\", \"loadPresentation\"]",
											"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
											"[\"quiz_result\", \"quiz_result\"]",
											"[\"scroll\", \"scroll\"]",
											"[\"set_score\", \"set_score\"]",
											"[\"surveyComplete\", \"surveyComplete\"]"
										],
										"timestamp" : [
											"[new Date(1389946609963), true)"
										],
										"_id" : [
											"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
											"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
										]
									},
									"keysExamined" : 14,
									"dupsTested" : 0,
									"dupsDropped" : 0,
									"seenInvalidated" : 0,
									"matchTested" : 0
								}
							}
						}
					}
				},
				{
					"shardName" : "eventsdata_1",
					"executionSuccess" : true,
					"executionStages" : {
						"stage" : "SORT",
						"nReturned" : 1,
						"executionTimeMillisEstimate" : 0,
						"works" : 17,
						"advanced" : 1,
						"needTime" : 14,
						"needFetch" : 0,
						"saveState" : 0,
						"restoreState" : 0,
						"isEOF" : 1,
						"invalidates" : 0,
						"sortPattern" : {
							"timestamp" : -1,
							"_id" : -1
						},
						"memUsage" : 972,
						"memLimit" : 33554432,
						"limitAmount" : 1,
						"inputStage" : {
							"stage" : "FETCH",
							"nReturned" : 9,
							"executionTimeMillisEstimate" : 0,
							"works" : 14,
							"advanced" : 9,
							"needTime" : 4,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 1,
							"invalidates" : 0,
							"docsExamined" : 9,
							"alreadyHasObj" : 0,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 9,
								"executionTimeMillisEstimate" : 0,
								"works" : 14,
								"advanced" : 9,
								"needTime" : 4,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 1,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "IXSCAN",
									"nReturned" : 9,
									"executionTimeMillisEstimate" : 0,
									"works" : 14,
									"advanced" : 9,
									"needTime" : 4,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 1,
									"invalidates" : 0,
									"keyPattern" : {
										"session_id" : 1,
										"event_type" : 1,
										"timestamp" : -1,
										"_id" : -1
									},
									"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
									"isMultiKey" : false,
									"direction" : "forward",
									"indexBounds" : {
										"session_id" : [
											"[\"1389946222338\", \"1389946222338\"]"
										],
										"event_type" : [
											"[\"changePDFPage\", \"changePDFPage\"]",
											"[\"closeMovie\", \"closeMovie\"]",
											"[\"closePDF\", \"closePDF\"]",
											"[\"closePresentation\", \"closePresentation\"]",
											"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
											"[\"deactivate\", \"deactivate\"]",
											"[\"endDetail\", \"endDetail\"]",
											"[\"exitApp\", \"exitApp\"]",
											"[\"lms_interaction\", \"lms_interaction\"]",
											"[\"loadMovie\", \"loadMovie\"]",
											"[\"loadPDF\", \"loadPDF\"]",
											"[\"loadPresentation\", \"loadPresentation\"]",
											"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
											"[\"quiz_result\", \"quiz_result\"]",
											"[\"scroll\", \"scroll\"]",
											"[\"set_score\", \"set_score\"]",
											"[\"surveyComplete\", \"surveyComplete\"]"
										],
										"timestamp" : [
											"[new Date(1389946609963), true)"
										],
										"_id" : [
											"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
											"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
										]
									},
									"keysExamined" : 13,
									"dupsTested" : 0,
									"dupsDropped" : 0,
									"seenInvalidated" : 0,
									"matchTested" : 0
								}
							}
						}
					}
				},
				{
					"shardName" : "eventsdata_2",
					"executionSuccess" : true,
					"executionStages" : {
						"stage" : "SORT",
						"nReturned" : 1,
						"executionTimeMillisEstimate" : 0,
						"works" : 20,
						"advanced" : 1,
						"needTime" : 17,
						"needFetch" : 0,
						"saveState" : 0,
						"restoreState" : 0,
						"isEOF" : 1,
						"invalidates" : 0,
						"sortPattern" : {
							"timestamp" : -1,
							"_id" : -1
						},
						"memUsage" : 972,
						"memLimit" : 33554432,
						"limitAmount" : 1,
						"inputStage" : {
							"stage" : "FETCH",
							"nReturned" : 11,
							"executionTimeMillisEstimate" : 0,
							"works" : 17,
							"advanced" : 11,
							"needTime" : 5,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 1,
							"invalidates" : 0,
							"docsExamined" : 11,
							"alreadyHasObj" : 0,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 11,
								"executionTimeMillisEstimate" : 0,
								"works" : 17,
								"advanced" : 11,
								"needTime" : 5,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 1,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "IXSCAN",
									"nReturned" : 11,
									"executionTimeMillisEstimate" : 0,
									"works" : 17,
									"advanced" : 11,
									"needTime" : 5,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 1,
									"invalidates" : 0,
									"keyPattern" : {
										"session_id" : 1,
										"event_type" : 1,
										"timestamp" : -1,
										"_id" : -1
									},
									"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
									"isMultiKey" : false,
									"direction" : "forward",
									"indexBounds" : {
										"session_id" : [
											"[\"1389946222338\", \"1389946222338\"]"
										],
										"event_type" : [
											"[\"changePDFPage\", \"changePDFPage\"]",
											"[\"closeMovie\", \"closeMovie\"]",
											"[\"closePDF\", \"closePDF\"]",
											"[\"closePresentation\", \"closePresentation\"]",
											"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
											"[\"deactivate\", \"deactivate\"]",
											"[\"endDetail\", \"endDetail\"]",
											"[\"exitApp\", \"exitApp\"]",
											"[\"lms_interaction\", \"lms_interaction\"]",
											"[\"loadMovie\", \"loadMovie\"]",
											"[\"loadPDF\", \"loadPDF\"]",
											"[\"loadPresentation\", \"loadPresentation\"]",
											"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
											"[\"quiz_result\", \"quiz_result\"]",
											"[\"scroll\", \"scroll\"]",
											"[\"set_score\", \"set_score\"]",
											"[\"surveyComplete\", \"surveyComplete\"]"
										],
										"timestamp" : [
											"[new Date(1389946609963), true)"
										],
										"_id" : [
											"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
											"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
										]
									},
									"keysExamined" : 16,
									"dupsTested" : 0,
									"dupsDropped" : 0,
									"seenInvalidated" : 0,
									"matchTested" : 0
								}
							}
						}
					}
				}
			]
		},
		"allPlansExecution" : [
			{
				"shardName" : "eventsdata_0",
				"allPlans" : [
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 16,
						"totalDocsExamined" : 16,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 17,
							"advanced" : 0,
							"needTime" : 16,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 0,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 0,
								"executionTimeMillisEstimate" : 0,
								"works" : 16,
								"advanced" : 0,
								"needTime" : 16,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											}
										]
									},
									"nReturned" : 0,
									"executionTimeMillisEstimate" : 0,
									"works" : 16,
									"advanced" : 0,
									"needTime" : 16,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 16,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 16,
										"executionTimeMillisEstimate" : 0,
										"works" : 16,
										"advanced" : 16,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"event_type" : 1
										},
										"indexName" : "event_type_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											]
										},
										"keysExamined" : 16,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 16,
						"totalDocsExamined" : 16,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 17,
							"advanced" : 0,
							"needTime" : 16,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 1015,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 7,
								"executionTimeMillisEstimate" : 0,
								"works" : 16,
								"advanced" : 7,
								"needTime" : 9,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 7,
									"executionTimeMillisEstimate" : 0,
									"works" : 16,
									"advanced" : 7,
									"needTime" : 9,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 16,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 16,
										"executionTimeMillisEstimate" : 0,
										"works" : 16,
										"advanced" : 16,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"session_id" : -1
										},
										"indexName" : "session_id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										},
										"keysExamined" : 16,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 16,
						"totalDocsExamined" : 16,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 17,
							"advanced" : 0,
							"needTime" : 16,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 1015,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 7,
								"executionTimeMillisEstimate" : 0,
								"works" : 16,
								"advanced" : 7,
								"needTime" : 9,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 7,
									"executionTimeMillisEstimate" : 0,
									"works" : 16,
									"advanced" : 7,
									"needTime" : 9,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 16,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 16,
										"executionTimeMillisEstimate" : 0,
										"works" : 16,
										"advanced" : 16,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"session_id" : 1
										},
										"indexName" : "session_id_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										},
										"keysExamined" : 16,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 16,
						"totalDocsExamined" : 16,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 17,
							"advanced" : 0,
							"needTime" : 16,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 1015,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 1,
								"executionTimeMillisEstimate" : 0,
								"works" : 16,
								"advanced" : 1,
								"needTime" : 15,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 1,
									"executionTimeMillisEstimate" : 0,
									"works" : 16,
									"advanced" : 1,
									"needTime" : 15,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 16,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 16,
										"executionTimeMillisEstimate" : 0,
										"works" : 16,
										"advanced" : 16,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"timestamp" : -1
										},
										"indexName" : "timestamp_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"timestamp" : [
												"[new Date(1389946609963), true)"
											]
										},
										"keysExamined" : 16,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 16,
						"totalDocsExamined" : 16,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 17,
							"advanced" : 0,
							"needTime" : 16,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 0,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 0,
								"executionTimeMillisEstimate" : 0,
								"works" : 16,
								"advanced" : 0,
								"needTime" : 16,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 0,
									"executionTimeMillisEstimate" : 0,
									"works" : 16,
									"advanced" : 0,
									"needTime" : 16,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 16,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 16,
										"executionTimeMillisEstimate" : 0,
										"works" : 16,
										"advanced" : 16,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"_id" : 1
										},
										"indexName" : "_id_",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"_id" : [
												"[MinKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MaxKey]"
											]
										},
										"keysExamined" : 16,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 1,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 14,
						"totalDocsExamined" : 10,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 1,
							"executionTimeMillisEstimate" : 0,
							"works" : 17,
							"advanced" : 1,
							"needTime" : 15,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 1,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 1015,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "FETCH",
								"nReturned" : 10,
								"executionTimeMillisEstimate" : 0,
								"works" : 15,
								"advanced" : 10,
								"needTime" : 4,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 1,
								"invalidates" : 0,
								"docsExamined" : 10,
								"alreadyHasObj" : 0,
								"inputStage" : {
									"stage" : "SHARDING_FILTER",
									"nReturned" : 10,
									"executionTimeMillisEstimate" : 0,
									"works" : 15,
									"advanced" : 10,
									"needTime" : 4,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 1,
									"invalidates" : 0,
									"chunkSkips" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 10,
										"executionTimeMillisEstimate" : 0,
										"works" : 15,
										"advanced" : 10,
										"needTime" : 4,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 1,
										"invalidates" : 0,
										"keyPattern" : {
											"session_id" : 1,
											"event_type" : 1,
											"timestamp" : -1,
											"_id" : -1
										},
										"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											],
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											],
											"timestamp" : [
												"[new Date(1389946609963), true)"
											],
											"_id" : [
												"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
											]
										},
										"keysExamined" : 14,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					}
				]
			},
			{
				"shardName" : "eventsdata_1",
				"allPlans" : [
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 15,
						"totalDocsExamined" : 15,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 16,
							"advanced" : 0,
							"needTime" : 15,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 0,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 0,
								"executionTimeMillisEstimate" : 0,
								"works" : 15,
								"advanced" : 0,
								"needTime" : 15,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											}
										]
									},
									"nReturned" : 0,
									"executionTimeMillisEstimate" : 0,
									"works" : 15,
									"advanced" : 0,
									"needTime" : 15,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 15,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 15,
										"executionTimeMillisEstimate" : 0,
										"works" : 15,
										"advanced" : 15,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"event_type" : 1
										},
										"indexName" : "event_type_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											]
										},
										"keysExamined" : 15,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 15,
						"totalDocsExamined" : 15,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 16,
							"advanced" : 0,
							"needTime" : 15,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 972,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 8,
								"executionTimeMillisEstimate" : 0,
								"works" : 15,
								"advanced" : 8,
								"needTime" : 7,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 8,
									"executionTimeMillisEstimate" : 0,
									"works" : 15,
									"advanced" : 8,
									"needTime" : 7,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 15,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 15,
										"executionTimeMillisEstimate" : 0,
										"works" : 15,
										"advanced" : 15,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"session_id" : -1
										},
										"indexName" : "session_id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										},
										"keysExamined" : 15,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 15,
						"totalDocsExamined" : 15,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 16,
							"advanced" : 0,
							"needTime" : 15,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 972,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 8,
								"executionTimeMillisEstimate" : 0,
								"works" : 15,
								"advanced" : 8,
								"needTime" : 7,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 8,
									"executionTimeMillisEstimate" : 0,
									"works" : 15,
									"advanced" : 8,
									"needTime" : 7,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 15,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 15,
										"executionTimeMillisEstimate" : 0,
										"works" : 15,
										"advanced" : 15,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"session_id" : 1
										},
										"indexName" : "session_id_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										},
										"keysExamined" : 15,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 15,
						"totalDocsExamined" : 15,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 16,
							"advanced" : 0,
							"needTime" : 15,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 972,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 2,
								"executionTimeMillisEstimate" : 0,
								"works" : 15,
								"advanced" : 2,
								"needTime" : 13,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 2,
									"executionTimeMillisEstimate" : 0,
									"works" : 15,
									"advanced" : 2,
									"needTime" : 13,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 15,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 15,
										"executionTimeMillisEstimate" : 0,
										"works" : 15,
										"advanced" : 15,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"timestamp" : -1
										},
										"indexName" : "timestamp_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"timestamp" : [
												"[new Date(1389946609963), true)"
											]
										},
										"keysExamined" : 15,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 15,
						"totalDocsExamined" : 15,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 16,
							"advanced" : 0,
							"needTime" : 15,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 0,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 0,
								"executionTimeMillisEstimate" : 0,
								"works" : 15,
								"advanced" : 0,
								"needTime" : 15,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 0,
									"executionTimeMillisEstimate" : 0,
									"works" : 15,
									"advanced" : 0,
									"needTime" : 15,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 15,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 15,
										"executionTimeMillisEstimate" : 0,
										"works" : 15,
										"advanced" : 15,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"_id" : 1
										},
										"indexName" : "_id_",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"_id" : [
												"[MinKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MaxKey]"
											]
										},
										"keysExamined" : 15,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 1,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 13,
						"totalDocsExamined" : 9,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 1,
							"executionTimeMillisEstimate" : 0,
							"works" : 16,
							"advanced" : 1,
							"needTime" : 14,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 1,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 972,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "FETCH",
								"nReturned" : 9,
								"executionTimeMillisEstimate" : 0,
								"works" : 14,
								"advanced" : 9,
								"needTime" : 4,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 1,
								"invalidates" : 0,
								"docsExamined" : 9,
								"alreadyHasObj" : 0,
								"inputStage" : {
									"stage" : "SHARDING_FILTER",
									"nReturned" : 9,
									"executionTimeMillisEstimate" : 0,
									"works" : 14,
									"advanced" : 9,
									"needTime" : 4,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 1,
									"invalidates" : 0,
									"chunkSkips" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 9,
										"executionTimeMillisEstimate" : 0,
										"works" : 14,
										"advanced" : 9,
										"needTime" : 4,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 1,
										"invalidates" : 0,
										"keyPattern" : {
											"session_id" : 1,
											"event_type" : 1,
											"timestamp" : -1,
											"_id" : -1
										},
										"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											],
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											],
											"timestamp" : [
												"[new Date(1389946609963), true)"
											],
											"_id" : [
												"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
											]
										},
										"keysExamined" : 13,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					}
				]
			},
			{
				"shardName" : "eventsdata_2",
				"allPlans" : [
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 18,
						"totalDocsExamined" : 18,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 19,
							"advanced" : 0,
							"needTime" : 18,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 0,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 0,
								"executionTimeMillisEstimate" : 0,
								"works" : 18,
								"advanced" : 0,
								"needTime" : 18,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											}
										]
									},
									"nReturned" : 0,
									"executionTimeMillisEstimate" : 0,
									"works" : 18,
									"advanced" : 0,
									"needTime" : 18,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 18,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 18,
										"executionTimeMillisEstimate" : 0,
										"works" : 18,
										"advanced" : 18,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"event_type" : 1
										},
										"indexName" : "event_type_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											]
										},
										"keysExamined" : 18,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 18,
						"totalDocsExamined" : 18,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 19,
							"advanced" : 0,
							"needTime" : 18,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 972,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 9,
								"executionTimeMillisEstimate" : 0,
								"works" : 18,
								"advanced" : 9,
								"needTime" : 9,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 9,
									"executionTimeMillisEstimate" : 0,
									"works" : 18,
									"advanced" : 9,
									"needTime" : 9,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 18,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 18,
										"executionTimeMillisEstimate" : 0,
										"works" : 18,
										"advanced" : 18,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"session_id" : -1
										},
										"indexName" : "session_id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										},
										"keysExamined" : 18,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 18,
						"totalDocsExamined" : 18,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 19,
							"advanced" : 0,
							"needTime" : 18,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 972,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 9,
								"executionTimeMillisEstimate" : 0,
								"works" : 18,
								"advanced" : 9,
								"needTime" : 9,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 9,
									"executionTimeMillisEstimate" : 0,
									"works" : 18,
									"advanced" : 9,
									"needTime" : 9,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 18,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 18,
										"executionTimeMillisEstimate" : 0,
										"works" : 18,
										"advanced" : 18,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"session_id" : 1
										},
										"indexName" : "session_id_1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											]
										},
										"keysExamined" : 18,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 18,
						"totalDocsExamined" : 18,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 19,
							"advanced" : 0,
							"needTime" : 18,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 0,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 0,
								"executionTimeMillisEstimate" : 0,
								"works" : 18,
								"advanced" : 0,
								"needTime" : 18,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"$not" : {
													"_id" : {
														"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
													}
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 0,
									"executionTimeMillisEstimate" : 0,
									"works" : 18,
									"advanced" : 0,
									"needTime" : 18,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 18,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 18,
										"executionTimeMillisEstimate" : 0,
										"works" : 18,
										"advanced" : 18,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"timestamp" : -1
										},
										"indexName" : "timestamp_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"timestamp" : [
												"[new Date(1389946609963), true)"
											]
										},
										"keysExamined" : 18,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 0,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 18,
						"totalDocsExamined" : 18,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 0,
							"executionTimeMillisEstimate" : 0,
							"works" : 19,
							"advanced" : 0,
							"needTime" : 18,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 0,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 0,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "SHARDING_FILTER",
								"nReturned" : 0,
								"executionTimeMillisEstimate" : 0,
								"works" : 18,
								"advanced" : 0,
								"needTime" : 18,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 0,
								"invalidates" : 0,
								"chunkSkips" : 0,
								"inputStage" : {
									"stage" : "FETCH",
									"filter" : {
										"$and" : [
											{
												"timestamp" : {
													"$lte" : ISODate("2014-01-17T08:16:49.963Z")
												}
											},
											{
												"session_id" : {
													"$eq" : "1389946222338"
												}
											},
											{
												"event_type" : {
													"$in" : [
														"changePDFPage",
														"closeMovie",
														"closePDF",
														"closePresentation",
														"closePresentationForJumping",
														"deactivate",
														"endDetail",
														"exitApp",
														"lms_interaction",
														"loadMovie",
														"loadPDF",
														"loadPresentation",
														"loadWebPageFromFolder",
														"quiz_result",
														"scroll",
														"set_score",
														"surveyComplete"
													]
												}
											}
										]
									},
									"nReturned" : 0,
									"executionTimeMillisEstimate" : 0,
									"works" : 18,
									"advanced" : 0,
									"needTime" : 18,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 0,
									"invalidates" : 0,
									"docsExamined" : 18,
									"alreadyHasObj" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 18,
										"executionTimeMillisEstimate" : 0,
										"works" : 18,
										"advanced" : 18,
										"needTime" : 0,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 0,
										"invalidates" : 0,
										"keyPattern" : {
											"_id" : 1
										},
										"indexName" : "_id_",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"_id" : [
												"[MinKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MaxKey]"
											]
										},
										"keysExamined" : 18,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					},
					{
						"nReturned" : 1,
						"executionTimeMillisEstimate" : 0,
						"totalKeysExamined" : 16,
						"totalDocsExamined" : 11,
						"executionStages" : {
							"stage" : "SORT",
							"nReturned" : 1,
							"executionTimeMillisEstimate" : 0,
							"works" : 19,
							"advanced" : 1,
							"needTime" : 17,
							"needFetch" : 0,
							"saveState" : 0,
							"restoreState" : 0,
							"isEOF" : 1,
							"invalidates" : 0,
							"sortPattern" : {
								"timestamp" : -1,
								"_id" : -1
							},
							"memUsage" : 972,
							"memLimit" : 33554432,
							"limitAmount" : 1,
							"inputStage" : {
								"stage" : "FETCH",
								"nReturned" : 11,
								"executionTimeMillisEstimate" : 0,
								"works" : 17,
								"advanced" : 11,
								"needTime" : 5,
								"needFetch" : 0,
								"saveState" : 0,
								"restoreState" : 0,
								"isEOF" : 1,
								"invalidates" : 0,
								"docsExamined" : 11,
								"alreadyHasObj" : 0,
								"inputStage" : {
									"stage" : "SHARDING_FILTER",
									"nReturned" : 11,
									"executionTimeMillisEstimate" : 0,
									"works" : 17,
									"advanced" : 11,
									"needTime" : 5,
									"needFetch" : 0,
									"saveState" : 0,
									"restoreState" : 0,
									"isEOF" : 1,
									"invalidates" : 0,
									"chunkSkips" : 0,
									"inputStage" : {
										"stage" : "IXSCAN",
										"nReturned" : 11,
										"executionTimeMillisEstimate" : 0,
										"works" : 17,
										"advanced" : 11,
										"needTime" : 5,
										"needFetch" : 0,
										"saveState" : 0,
										"restoreState" : 0,
										"isEOF" : 1,
										"invalidates" : 0,
										"keyPattern" : {
											"session_id" : 1,
											"event_type" : 1,
											"timestamp" : -1,
											"_id" : -1
										},
										"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											],
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											],
											"timestamp" : [
												"[new Date(1389946609963), true)"
											],
											"_id" : [
												"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
											]
										},
										"keysExamined" : 16,
										"dupsTested" : 0,
										"dupsDropped" : 0,
										"seenInvalidated" : 0,
										"matchTested" : 0
									}
								}
							}
						}
					}
				]
			}
		]
	},
	"ok" : 1
}

Comment by Patrick Lauber [ 10/Jun/15 ]

the output is as follows:

db.setLogLevel(1)
{
	"was" : {
		"verbosity" : 1,
		"accessControl" : {
			"verbosity" : -1
		},
		"command" : {
			"verbosity" : -1
		},
		"control" : {
			"verbosity" : -1
		},
		"geo" : {
			"verbosity" : -1
		},
		"index" : {
			"verbosity" : -1
		},
		"network" : {
			"verbosity" : -1
		},
		"query" : {
			"verbosity" : -1
		},
		"replication" : {
			"verbosity" : -1
		},
		"sharding" : {
			"verbosity" : -1
		},
		"storage" : {
			"verbosity" : -1,
			"journal" : {
				"verbosity" : -1
			}
		},
		"write" : {
			"verbosity" : -1
		}
	},
	"ok" : 1
}

mongos> db.all_events.getIndexes()
[
	{
		"v" : 1,
		"key" : {
			"_id" : 1
		},
		"name" : "_id_",
		"ns" : "events.all_events"
	},
	{
		"v" : 1,
		"key" : {
			"timestamp" : -1
		},
		"name" : "timestamp_-1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"_id" : "hashed"
		},
		"name" : "_id_hashed",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"session_id" : 1
		},
		"name" : "session_id_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"event_type" : 1
		},
		"name" : "event_type_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"geo:tag" : 1,
			"lat" : 1
		},
		"name" : "geo:tag_1_lat_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"geo:ip" : 1,
			"ip" : 1
		},
		"name" : "geo:ip_1_ip_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"geo:ip" : 1
		},
		"name" : "geo:ip_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"geo:tag" : 1
		},
		"name" : "geo:tag_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"lat" : 1
		},
		"name" : "lat_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"session_id" : -1
		},
		"name" : "session_id_-1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"event_day" : 1
		},
		"name" : "event_day_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"event_name" : 1
		},
		"name" : "event_name_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"rep_name" : 1
		},
		"name" : "rep_name_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"app_slug" : 1
		},
		"name" : "app_slug_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"app_name" : 1
		},
		"name" : "app_name_1",
		"ns" : "events.all_events",
		"background" : true
	},
	{
		"v" : 1,
		"key" : {
			"session_id" : 1,
			"event_type" : 1,
			"timestamp" : -1,
			"_id" : -1
		},
		"name" : "session_id_1_event_type_1_timestamp_-1__id_-1",
		"ns" : "events.all_events",
		"background" : true
	}
]

mongos> db.all_events.aggregate([{$match:{'session_id':'1389946222338', 'event_type': {'$in': PREV_EVENTS}, 'timestamp': {'$lte': ISODate("2014-01-17T08:16:49.963Z")}, _id:{$ne:ObjectId('555b4b1c6d5ba860366c78e2')}}}, {$sort:{timestamp:-1, _id:-1}}, {$limit:1}], {explain : true})
{
	"splitPipeline" : {
		"shardsPart" : [
			{
				"$match" : {
					"session_id" : "1389946222338",
					"event_type" : {
						"$in" : [
							"scroll",
							"changePDFPage",
							"surveyComplete",
							"quiz_result",
							"lms_interaction",
							"set_score",
							"loadPDF",
							"loadMovie",
							"loadPresentation",
							"loadWebPageFromFolder",
							"closeMovie",
							"closePDF",
							"closePresentation",
							"closePresentationForJumping",
							"exitApp",
							"endDetail",
							"deactivate"
						]
					},
					"timestamp" : {
						"$lte" : ISODate("2014-01-17T08:16:49.963Z")
					},
					"_id" : {
						"$ne" : ObjectId("555b4b1c6d5ba860366c78e2")
					}
				}
			},
			{
				"$sort" : {
					"sortKey" : {
						"timestamp" : -1,
						"_id" : -1
					},
					"limit" : NumberLong(1)
				}
			}
		],
		"mergerPart" : [
			{
				"$sort" : {
					"sortKey" : {
						"timestamp" : -1,
						"_id" : -1
					},
					"mergePresorted" : true,
					"limit" : NumberLong(1)
				}
			}
		]
	},
	"shards" : {
		"eventsdata_0" : {
			"host" : "events-cluster-20.pitcher.9790.mongodbdns.com:27000",
			"stages" : [
				{
					"$cursor" : {
						"query" : {
							"session_id" : "1389946222338",
							"event_type" : {
								"$in" : [
									"scroll",
									"changePDFPage",
									"surveyComplete",
									"quiz_result",
									"lms_interaction",
									"set_score",
									"loadPDF",
									"loadMovie",
									"loadPresentation",
									"loadWebPageFromFolder",
									"closeMovie",
									"closePDF",
									"closePresentation",
									"closePresentationForJumping",
									"exitApp",
									"endDetail",
									"deactivate"
								]
							},
							"timestamp" : {
								"$lte" : ISODate("2014-01-17T08:16:49.963Z")
							},
							"_id" : {
								"$ne" : ObjectId("555b4b1c6d5ba860366c78e2")
							}
						},
						"queryPlanner" : {
							"plannerVersion" : 1,
							"namespace" : "events.all_events",
							"indexFilterSet" : false,
							"parsedQuery" : {
								"$and" : [
									{
										"$not" : {
											"_id" : {
												"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
											}
										}
									},
									{
										"timestamp" : {
											"$lte" : ISODate("2014-01-17T08:16:49.963Z")
										}
									},
									{
										"session_id" : {
											"$eq" : "1389946222338"
										}
									},
									{
										"event_type" : {
											"$in" : [
												"changePDFPage",
												"closeMovie",
												"closePDF",
												"closePresentation",
												"closePresentationForJumping",
												"deactivate",
												"endDetail",
												"exitApp",
												"lms_interaction",
												"loadMovie",
												"loadPDF",
												"loadPresentation",
												"loadWebPageFromFolder",
												"quiz_result",
												"scroll",
												"set_score",
												"surveyComplete"
											]
										}
									}
								]
							},
							"winningPlan" : {
								"stage" : "FETCH",
								"inputStage" : {
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"session_id" : 1,
											"event_type" : 1,
											"timestamp" : -1,
											"_id" : -1
										},
										"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											],
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											],
											"timestamp" : [
												"[new Date(1389946609963), true)"
											],
											"_id" : [
												"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
											]
										}
									}
								}
							},
							"rejectedPlans" : [
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"session_id" : {
														"$eq" : "1389946222338"
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"event_type" : 1
											},
											"indexName" : "event_type_1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"event_type" : [
													"[\"changePDFPage\", \"changePDFPage\"]",
													"[\"closeMovie\", \"closeMovie\"]",
													"[\"closePDF\", \"closePDF\"]",
													"[\"closePresentation\", \"closePresentation\"]",
													"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
													"[\"deactivate\", \"deactivate\"]",
													"[\"endDetail\", \"endDetail\"]",
													"[\"exitApp\", \"exitApp\"]",
													"[\"lms_interaction\", \"lms_interaction\"]",
													"[\"loadMovie\", \"loadMovie\"]",
													"[\"loadPDF\", \"loadPDF\"]",
													"[\"loadPresentation\", \"loadPresentation\"]",
													"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
													"[\"quiz_result\", \"quiz_result\"]",
													"[\"scroll\", \"scroll\"]",
													"[\"set_score\", \"set_score\"]",
													"[\"surveyComplete\", \"surveyComplete\"]"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"session_id" : -1
											},
											"indexName" : "session_id_-1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"session_id" : [
													"[\"1389946222338\", \"1389946222338\"]"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"session_id" : 1
											},
											"indexName" : "session_id_1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"session_id" : [
													"[\"1389946222338\", \"1389946222338\"]"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"session_id" : {
														"$eq" : "1389946222338"
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"timestamp" : -1
											},
											"indexName" : "timestamp_-1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"timestamp" : [
													"[new Date(1389946609963), true)"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"session_id" : {
														"$eq" : "1389946222338"
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"_id" : 1
											},
											"indexName" : "_id_",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"_id" : [
													"[MinKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
													"(ObjectId('555b4b1c6d5ba860366c78e2'), MaxKey]"
												]
											}
										}
									}
								}
							]
						}
					}
				},
				{
					"$sort" : {
						"sortKey" : {
							"timestamp" : -1,
							"_id" : -1
						},
						"limit" : NumberLong(1)
					}
				}
			]
		},
		"eventsdata_1" : {
			"host" : "events-cluster-22.pitcher.9790.mongodbdns.com:27000",
			"stages" : [
				{
					"$cursor" : {
						"query" : {
							"session_id" : "1389946222338",
							"event_type" : {
								"$in" : [
									"scroll",
									"changePDFPage",
									"surveyComplete",
									"quiz_result",
									"lms_interaction",
									"set_score",
									"loadPDF",
									"loadMovie",
									"loadPresentation",
									"loadWebPageFromFolder",
									"closeMovie",
									"closePDF",
									"closePresentation",
									"closePresentationForJumping",
									"exitApp",
									"endDetail",
									"deactivate"
								]
							},
							"timestamp" : {
								"$lte" : ISODate("2014-01-17T08:16:49.963Z")
							},
							"_id" : {
								"$ne" : ObjectId("555b4b1c6d5ba860366c78e2")
							}
						},
						"queryPlanner" : {
							"plannerVersion" : 1,
							"namespace" : "events.all_events",
							"indexFilterSet" : false,
							"parsedQuery" : {
								"$and" : [
									{
										"$not" : {
											"_id" : {
												"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
											}
										}
									},
									{
										"timestamp" : {
											"$lte" : ISODate("2014-01-17T08:16:49.963Z")
										}
									},
									{
										"session_id" : {
											"$eq" : "1389946222338"
										}
									},
									{
										"event_type" : {
											"$in" : [
												"changePDFPage",
												"closeMovie",
												"closePDF",
												"closePresentation",
												"closePresentationForJumping",
												"deactivate",
												"endDetail",
												"exitApp",
												"lms_interaction",
												"loadMovie",
												"loadPDF",
												"loadPresentation",
												"loadWebPageFromFolder",
												"quiz_result",
												"scroll",
												"set_score",
												"surveyComplete"
											]
										}
									}
								]
							},
							"winningPlan" : {
								"stage" : "FETCH",
								"inputStage" : {
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"session_id" : 1,
											"event_type" : 1,
											"timestamp" : -1,
											"_id" : -1
										},
										"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											],
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											],
											"timestamp" : [
												"[new Date(1389946609963), true)"
											],
											"_id" : [
												"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
											]
										}
									}
								}
							},
							"rejectedPlans" : [
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"session_id" : {
														"$eq" : "1389946222338"
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"event_type" : 1
											},
											"indexName" : "event_type_1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"event_type" : [
													"[\"changePDFPage\", \"changePDFPage\"]",
													"[\"closeMovie\", \"closeMovie\"]",
													"[\"closePDF\", \"closePDF\"]",
													"[\"closePresentation\", \"closePresentation\"]",
													"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
													"[\"deactivate\", \"deactivate\"]",
													"[\"endDetail\", \"endDetail\"]",
													"[\"exitApp\", \"exitApp\"]",
													"[\"lms_interaction\", \"lms_interaction\"]",
													"[\"loadMovie\", \"loadMovie\"]",
													"[\"loadPDF\", \"loadPDF\"]",
													"[\"loadPresentation\", \"loadPresentation\"]",
													"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
													"[\"quiz_result\", \"quiz_result\"]",
													"[\"scroll\", \"scroll\"]",
													"[\"set_score\", \"set_score\"]",
													"[\"surveyComplete\", \"surveyComplete\"]"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"session_id" : -1
											},
											"indexName" : "session_id_-1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"session_id" : [
													"[\"1389946222338\", \"1389946222338\"]"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"session_id" : 1
											},
											"indexName" : "session_id_1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"session_id" : [
													"[\"1389946222338\", \"1389946222338\"]"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"session_id" : {
														"$eq" : "1389946222338"
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"timestamp" : -1
											},
											"indexName" : "timestamp_-1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"timestamp" : [
													"[new Date(1389946609963), true)"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"session_id" : {
														"$eq" : "1389946222338"
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"_id" : 1
											},
											"indexName" : "_id_",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"_id" : [
													"[MinKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
													"(ObjectId('555b4b1c6d5ba860366c78e2'), MaxKey]"
												]
											}
										}
									}
								}
							]
						}
					}
				},
				{
					"$sort" : {
						"sortKey" : {
							"timestamp" : -1,
							"_id" : -1
						},
						"limit" : NumberLong(1)
					}
				}
			]
		},
		"eventsdata_2" : {
			"host" : "events-cluster-23.pitcher.9790.mongodbdns.com:27000",
			"stages" : [
				{
					"$cursor" : {
						"query" : {
							"session_id" : "1389946222338",
							"event_type" : {
								"$in" : [
									"scroll",
									"changePDFPage",
									"surveyComplete",
									"quiz_result",
									"lms_interaction",
									"set_score",
									"loadPDF",
									"loadMovie",
									"loadPresentation",
									"loadWebPageFromFolder",
									"closeMovie",
									"closePDF",
									"closePresentation",
									"closePresentationForJumping",
									"exitApp",
									"endDetail",
									"deactivate"
								]
							},
							"timestamp" : {
								"$lte" : ISODate("2014-01-17T08:16:49.963Z")
							},
							"_id" : {
								"$ne" : ObjectId("555b4b1c6d5ba860366c78e2")
							}
						},
						"queryPlanner" : {
							"plannerVersion" : 1,
							"namespace" : "events.all_events",
							"indexFilterSet" : false,
							"parsedQuery" : {
								"$and" : [
									{
										"$not" : {
											"_id" : {
												"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
											}
										}
									},
									{
										"timestamp" : {
											"$lte" : ISODate("2014-01-17T08:16:49.963Z")
										}
									},
									{
										"session_id" : {
											"$eq" : "1389946222338"
										}
									},
									{
										"event_type" : {
											"$in" : [
												"changePDFPage",
												"closeMovie",
												"closePDF",
												"closePresentation",
												"closePresentationForJumping",
												"deactivate",
												"endDetail",
												"exitApp",
												"lms_interaction",
												"loadMovie",
												"loadPDF",
												"loadPresentation",
												"loadWebPageFromFolder",
												"quiz_result",
												"scroll",
												"set_score",
												"surveyComplete"
											]
										}
									}
								]
							},
							"winningPlan" : {
								"stage" : "FETCH",
								"inputStage" : {
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "IXSCAN",
										"keyPattern" : {
											"session_id" : 1,
											"event_type" : 1,
											"timestamp" : -1,
											"_id" : -1
										},
										"indexName" : "session_id_1_event_type_1_timestamp_-1__id_-1",
										"isMultiKey" : false,
										"direction" : "forward",
										"indexBounds" : {
											"session_id" : [
												"[\"1389946222338\", \"1389946222338\"]"
											],
											"event_type" : [
												"[\"changePDFPage\", \"changePDFPage\"]",
												"[\"closeMovie\", \"closeMovie\"]",
												"[\"closePDF\", \"closePDF\"]",
												"[\"closePresentation\", \"closePresentation\"]",
												"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
												"[\"deactivate\", \"deactivate\"]",
												"[\"endDetail\", \"endDetail\"]",
												"[\"exitApp\", \"exitApp\"]",
												"[\"lms_interaction\", \"lms_interaction\"]",
												"[\"loadMovie\", \"loadMovie\"]",
												"[\"loadPDF\", \"loadPDF\"]",
												"[\"loadPresentation\", \"loadPresentation\"]",
												"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
												"[\"quiz_result\", \"quiz_result\"]",
												"[\"scroll\", \"scroll\"]",
												"[\"set_score\", \"set_score\"]",
												"[\"surveyComplete\", \"surveyComplete\"]"
											],
											"timestamp" : [
												"[new Date(1389946609963), true)"
											],
											"_id" : [
												"[MaxKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
												"(ObjectId('555b4b1c6d5ba860366c78e2'), MinKey]"
											]
										}
									}
								}
							},
							"rejectedPlans" : [
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"session_id" : {
														"$eq" : "1389946222338"
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"event_type" : 1
											},
											"indexName" : "event_type_1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"event_type" : [
													"[\"changePDFPage\", \"changePDFPage\"]",
													"[\"closeMovie\", \"closeMovie\"]",
													"[\"closePDF\", \"closePDF\"]",
													"[\"closePresentation\", \"closePresentation\"]",
													"[\"closePresentationForJumping\", \"closePresentationForJumping\"]",
													"[\"deactivate\", \"deactivate\"]",
													"[\"endDetail\", \"endDetail\"]",
													"[\"exitApp\", \"exitApp\"]",
													"[\"lms_interaction\", \"lms_interaction\"]",
													"[\"loadMovie\", \"loadMovie\"]",
													"[\"loadPDF\", \"loadPDF\"]",
													"[\"loadPresentation\", \"loadPresentation\"]",
													"[\"loadWebPageFromFolder\", \"loadWebPageFromFolder\"]",
													"[\"quiz_result\", \"quiz_result\"]",
													"[\"scroll\", \"scroll\"]",
													"[\"set_score\", \"set_score\"]",
													"[\"surveyComplete\", \"surveyComplete\"]"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"session_id" : -1
											},
											"indexName" : "session_id_-1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"session_id" : [
													"[\"1389946222338\", \"1389946222338\"]"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"session_id" : 1
											},
											"indexName" : "session_id_1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"session_id" : [
													"[\"1389946222338\", \"1389946222338\"]"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"$not" : {
														"_id" : {
															"$eq" : ObjectId("555b4b1c6d5ba860366c78e2")
														}
													}
												},
												{
													"session_id" : {
														"$eq" : "1389946222338"
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"timestamp" : -1
											},
											"indexName" : "timestamp_-1",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"timestamp" : [
													"[new Date(1389946609963), true)"
												]
											}
										}
									}
								},
								{
									"stage" : "SHARDING_FILTER",
									"inputStage" : {
										"stage" : "FETCH",
										"filter" : {
											"$and" : [
												{
													"timestamp" : {
														"$lte" : ISODate("2014-01-17T08:16:49.963Z")
													}
												},
												{
													"session_id" : {
														"$eq" : "1389946222338"
													}
												},
												{
													"event_type" : {
														"$in" : [
															"changePDFPage",
															"closeMovie",
															"closePDF",
															"closePresentation",
															"closePresentationForJumping",
															"deactivate",
															"endDetail",
															"exitApp",
															"lms_interaction",
															"loadMovie",
															"loadPDF",
															"loadPresentation",
															"loadWebPageFromFolder",
															"quiz_result",
															"scroll",
															"set_score",
															"surveyComplete"
														]
													}
												}
											]
										},
										"inputStage" : {
											"stage" : "IXSCAN",
											"keyPattern" : {
												"_id" : 1
											},
											"indexName" : "_id_",
											"isMultiKey" : false,
											"direction" : "forward",
											"indexBounds" : {
												"_id" : [
													"[MinKey, ObjectId('555b4b1c6d5ba860366c78e2'))",
													"(ObjectId('555b4b1c6d5ba860366c78e2'), MaxKey]"
												]
											}
										}
									}
								}
							]
						}
					}
				},
				{
					"$sort" : {
						"sortKey" : {
							"timestamp" : -1,
							"_id" : -1
						},
						"limit" : NumberLong(1)
					}
				}
			]
		}
	},
	"ok" : 1
}

mongos> db.all_events.find({'session_id':'1389946222338', 'event_type': {'$in': PREV_EVENTS}, 'timestamp': {'$lte': ISODate("2014-01-17T08:16:49.963Z")}, '_id': {'$ne': ObjectId('555b4b1c6d5ba860366c78e2')}}).sort([('timestamp', -1), ('_id', -1)]).limit(1).explain(true)
2015-06-10T14:53:48.823+0200 E QUERY    Error: explain failed: {
	"ok" : 0,
	"errmsg" : "Failed to parse: sort: [ -1.0, -1.0 ]. 'sort' field must be of BSON type Object.",
	"code" : 2
}
    at Error (<anonymous>)
    at Function.throwOrReturn (src/mongo/shell/explainable.js:34:19)
    at constructor.finish (src/mongo/shell/explain_query.js:188:36)
    at DBQuery.explain (src/mongo/shell/query.js:434:25)
    at (shell):1:250 at src/mongo/shell/explainable.js:34

Comment by Ramon Fernandez Marina [ 10/Jun/15 ]

digi604, can you please run the commands below and send us the output?

db.setLogLevel(1)
db.all_events.getIndexes()
db.all_events.aggregate([{$match:{'session_id':'1389946222338', 'event_type': {'$in': PREV_EVENTS}, 'timestamp': {'$lte': ISODate("2014-01-17T08:16:49.963Z")}, _id:{$ne:ObjectId('555b4b1c6d5ba860366c78e2')}}}, {$sort:{timestamp:-1, _id:-1}}, {$limit:1}], {explain : true})
db.all_events.find({'session_id':'1389946222338', 'event_type': {'$in': PREV_EVENTS}, 'timestamp': {'$lte': ISODate("2014-01-17T08:16:49.963Z")}, '_id': {'$ne': ObjectId('555b4b1c6d5ba860366c78e2')}}).sort([('timestamp', -1), ('_id', -1)]).limit(1).explain(true)

Also, can you send us logs from this server containing at least the first few lines after starting (so we can see all the options this mongod is running with) and the lines produced when running the commands above?

Thanks,
Ramón.

Generated at Thu Feb 08 03:49:06 UTC 2024 using Jira 9.7.1#970001-sha1:2222b88b221c4928ef0de3161136cc90c8356a66.