Unexpected query plan for a $or condition

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    • Type: Bug
    • Resolution: Done
    • Priority: Major - P3
    • None
    • Affects Version/s: 2.4.1
    • Component/s: Querying
    • ALL
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      Reproduce:

      db.files.drop();

db.files.insert({ _id:"foo.txt", attr: [ { type: "text" },   { size: 64 } ] } )
db.files.insert({ _id:"bar.txt", attr: [ { type: "text" },   { size: 128 }, { created: ISODate("2013-01-01T18:13:42.689Z") } ] } )
db.files.insert({ _id:"foobar",  attr: [ { type: "binary" }, { size: 256 }, { created: ISODate("2013-04-01T18:13:42.689Z") } ] } )

db.files.ensureIndex({attr: 1})

db.files.find( { $or: [ { attr: { $gte: { created: ISODate("2013-02-01T00:00:01.689Z") } } },  
                        { attr: { $gt: { size:128 }, $lte: { size: 16384 } } }
                       ] } ).explain()
      Show
      Reproduce: db.files.drop(); db.files.insert({ _id: "foo.txt" , attr: [ { type: "text" }, { size: 64 } ] } ) db.files.insert({ _id: "bar.txt" , attr: [ { type: "text" }, { size: 128 }, { created: ISODate( "2013-01-01T18:13:42.689Z" ) } ] } ) db.files.insert({ _id: "foobar" , attr: [ { type: "binary" }, { size: 256 }, { created: ISODate( "2013-04-01T18:13:42.689Z" ) } ] } ) db.files.ensureIndex({attr: 1}) db.files.find( { $or: [ { attr: { $gte: { created: ISODate( "2013-02-01T00:00:01.689Z" ) } } }, { attr: { $gt: { size:128 }, $lte: { size: 16384 } } } ] } ).explain()
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      Problem:
      Seeing the index bounds for a single element of a $or reference items in another element of the $or.

      Example:
      See the second element of the query plan, where bounds are "size" and "created" (lines 46 and 49 below)

      {
	"clauses" : [
		{
			"cursor" : "BtreeCursor attr_1",
			"isMultiKey" : true,
			"n" : 1,
			"nscannedObjects" : 1,
			"nscanned" : 1,
			"nscannedObjectsAllPlans" : 1,
			"nscannedAllPlans" : 1,
			"scanAndOrder" : false,
			"indexOnly" : false,
			"nYields" : 0,
			"nChunkSkips" : 0,
			"millis" : 0,
			"indexBounds" : {
				"attr" : [
					[
						{
							"created" : ISODate("2013-02-01T00:00:01.689Z")
						},
						{
							"$maxElement" : 1
						}
					]
				]
			}
		},
		{
			"cursor" : "BtreeCursor attr_1",
			"isMultiKey" : true,
			"n" : 2,
			"nscannedObjects" : 5,
			"nscanned" : 5,
			"nscannedObjectsAllPlans" : 5,
			"nscannedAllPlans" : 5,
			"scanAndOrder" : false,
			"indexOnly" : false,
			"nYields" : 0,
			"nChunkSkips" : 0,
			"millis" : 0,
			"indexBounds" : {
				"attr" : [
					[
						{
							"size" : 128
						},
						{
							"created" : ISODate("2013-02-01T00:00:01.689Z")
						}
					]
				]
			}
		}
	],
	"n" : 3,
	"nscannedObjects" : 6,
	"nscanned" : 6,
	"nscannedObjectsAllPlans" : 6,
	"nscannedAllPlans" : 6,
	"millis" : 0,
	"server" : "vero:27017"
}

        1. server9207.js
          2 kB
          Benety Goh

            Assignee:
            David Storch
            Reporter:
            Alvin Richards (Inactive)
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            0 Vote for this issue
            Watchers:
            4 Start watching this issue

              Created:
              Updated:
              Resolved: