Running db.collection.validate(

) for 2.8 mmapv1 gives empty "indexDetails" stats in the resulting document while for 2.8 WT, it gives the non-empty results for "indexDetails" stats.

• In 2.8 WT:

  > db.foo.validate({full:true})
  {
  	"ns" : "test.foo",
  	"nrecords" : 10000,
  	"wiredTiger" : {
  		"uri" : "statistics:table:collection-2-632245492128970716",
  		"LSM" : {
  			"bloom filters in the LSM tree" : 0,
  			"bloom filter false positives" : 0,
  			"bloom filter hits" : 0,
  			"bloom filter misses" : 0,
  			"bloom filter pages evicted from cache" : 0,
  			"bloom filter pages read into cache" : 0,
  			"total size of bloom filters" : 0,
  			"sleep for LSM checkpoint throttle" : 0,
  			"chunks in the LSM tree" : 0,
  			"highest merge generation in the LSM tree" : 0,
  			"queries that could have benefited from a Bloom filter that did not exist" : 0,
  			"sleep for LSM merge throttle" : 0
  		},
  		"block-manager" : {
  			"file allocation unit size" : 4096,
  			"blocks allocated" : 9,
  			"checkpoint size" : 32768,
  			"allocations requiring file extension" : 6,
  			"blocks freed" : 3,
  			"file magic number" : 120897,
  			"file major version number" : 1,
  			"minor version number" : 0,
  			"file bytes available for reuse" : 16384,
  			"file size in bytes" : 61440
  		},
  		"btree" : {
  			"column-store variable-size deleted values" : 0,
  			"column-store fixed-size leaf pages" : 0,
  			"column-store internal pages" : 0,
  			"column-store variable-size leaf pages" : 0,
  			"pages rewritten by compaction" : 0,
  			"number of key/value pairs" : 0,
  			"fixed-record size" : 0,
  			"maximum tree depth" : 3,
  			"maximum internal page item size" : 384,
  			"maximum internal page size" : 4096,
  			"maximum leaf page item size" : 3072,
  			"maximum leaf page size" : 32768,
  			"overflow pages" : 0,
  			"row-store internal pages" : 0,
  			"row-store leaf pages" : 0
  		},
  		"cache" : {
  			"bytes read into cache" : 0,
  			"bytes written from cache" : 46021,
  			"checkpoint blocked page eviction" : 0,
  			"unmodified pages evicted" : 0,
  			"modified pages evicted" : 0,
  			"data source pages selected for eviction unable to be evicted" : 0,
  			"hazard pointer blocked page eviction" : 0,
  			"internal pages evicted" : 0,
  			"in-memory page splits" : 0,
  			"overflow values cached in memory" : 0,
  			"pages read into cache" : 0,
  			"overflow pages read into cache" : 0,
  			"pages written from cache" : 7
  		},
  		"compression" : {
  			"raw compression call failed, no additional data available" : 0,
  			"raw compression call failed, additional data available" : 0,
  			"raw compression call succeeded" : 0,
  			"compressed pages read" : 0,
  			"compressed pages written" : 6,
  			"page written failed to compress" : 0,
  			"page written was too small to compress" : 1
  		},
  		"cursor" : {
  			"create calls" : 3,
  			"insert calls" : 10000,
  			"bulk-loaded cursor-insert calls" : 0,
  			"cursor-insert key and value bytes inserted" : 351426,
  			"next calls" : 10001,
  			"prev calls" : 1,
  			"remove calls" : 0,
  			"cursor-remove key bytes removed" : 0,
  			"reset calls" : 20001,
  			"search calls" : 10000,
  			"search near calls" : 0,
  			"update calls" : 0,
  			"cursor-update value bytes updated" : 0
  		},
  		"reconciliation" : {
  			"dictionary matches" : 0,
  			"internal page multi-block writes" : 0,
  			"leaf page multi-block writes" : 2,
  			"maximum blocks required for a page" : 3,
  			"internal-page overflow keys" : 0,
  			"leaf-page overflow keys" : 0,
  			"overflow values written" : 0,
  			"pages deleted" : 0,
  			"page checksum matches" : 0,
  			"page reconciliation calls" : 3,
  			"page reconciliation calls for eviction" : 0,
  			"leaf page key bytes discarded using prefix compression" : 0,
  			"internal page key bytes discarded using suffix compression" : 4
  		},
  		"session" : {
  			"object compaction" : 0,
  			"open cursor count" : 3
  		},
  		"transaction" : {
  			"update conflicts" : 0
  		}
  	},
  	"nIndexes" : 1,
  	"keysPerIndex" : {
  		"test.foo.$_id_" : 10000
  	},
  	"indexDetails" : {
  		"test.foo.$_id_" : {
  			"uri" : "statistics:table:index-3-632245492128970716",
  			"LSM" : {
  				"bloom filters in the LSM tree" : 0,
  				"bloom filter false positives" : 0,
  				"bloom filter hits" : 0,
  				"bloom filter misses" : 0,
  				"bloom filter pages evicted from cache" : 0,
  				"bloom filter pages read into cache" : 0,
  				"total size of bloom filters" : 0,
  				"sleep for LSM checkpoint throttle" : 0,
  				"chunks in the LSM tree" : 0,
  				"highest merge generation in the LSM tree" : 0,
  				"queries that could have benefited from a Bloom filter that did not exist" : 0,
  				"sleep for LSM merge throttle" : 0
  			},
  			"block-manager" : {
  				"file allocation unit size" : 4096,
  				"blocks allocated" : 8,
  				"checkpoint size" : 32768,
  				"allocations requiring file extension" : 5,
  				"blocks freed" : 2,
  				"file magic number" : 120897,
  				"file major version number" : 1,
  				"minor version number" : 0,
  				"file bytes available for reuse" : 12288,
  				"file size in bytes" : 57344
  			},
  			"btree" : {
  				"column-store variable-size deleted values" : 0,
  				"column-store fixed-size leaf pages" : 0,
  				"column-store internal pages" : 0,
  				"column-store variable-size leaf pages" : 0,
  				"pages rewritten by compaction" : 0,
  				"number of key/value pairs" : 0,
  				"fixed-record size" : 0,
  				"maximum tree depth" : 3,
  				"maximum internal page item size" : 384,
  				"maximum internal page size" : 4096,
  				"maximum leaf page item size" : 1536,
  				"maximum leaf page size" : 16384,
  				"overflow pages" : 0,
  				"row-store internal pages" : 0,
  				"row-store leaf pages" : 0
  			},
  			"cache" : {
  				"bytes read into cache" : 0,
  				"bytes written from cache" : 49474,
  				"checkpoint blocked page eviction" : 0,
  				"unmodified pages evicted" : 0,
  				"modified pages evicted" : 0,
  				"data source pages selected for eviction unable to be evicted" : 0,
  				"hazard pointer blocked page eviction" : 0,
  				"internal pages evicted" : 0,
  				"in-memory page splits" : 0,
  				"overflow values cached in memory" : 0,
  				"pages read into cache" : 0,
  				"overflow pages read into cache" : 0,
  				"pages written from cache" : 6
  			},
  			"compression" : {
  				"raw compression call failed, no additional data available" : 0,
  				"raw compression call failed, additional data available" : 0,
  				"raw compression call succeeded" : 0,
  				"compressed pages read" : 0,
  				"compressed pages written" : 0,
  				"page written failed to compress" : 0,
  				"page written was too small to compress" : 0
  			},
  			"cursor" : {
  				"create calls" : 2,
  				"insert calls" : 10000,
  				"bulk-loaded cursor-insert calls" : 0,
  				"cursor-insert key and value bytes inserted" : 270000,
  				"next calls" : 10000,
  				"prev calls" : 0,
  				"remove calls" : 0,
  				"cursor-remove key bytes removed" : 0,
  				"reset calls" : 10000,
  				"search calls" : 0,
  				"search near calls" : 1,
  				"update calls" : 0,
  				"cursor-update value bytes updated" : 0
  			},
  			"reconciliation" : {
  				"dictionary matches" : 0,
  				"internal page multi-block writes" : 0,
  				"leaf page multi-block writes" : 2,
  				"maximum blocks required for a page" : 2,
  				"internal-page overflow keys" : 0,
  				"leaf-page overflow keys" : 0,
  				"overflow values written" : 0,
  				"pages deleted" : 0,
  				"page checksum matches" : 0,
  				"page reconciliation calls" : 3,
  				"page reconciliation calls for eviction" : 0,
  				"leaf page key bytes discarded using prefix compression" : 64043,
  				"internal page key bytes discarded using suffix compression" : 0
  			},
  			"session" : {
  				"object compaction" : 0,
  				"open cursor count" : 2
  			},
  			"transaction" : {
  				"update conflicts" : 0
  			}
  		}
  	},
  	"valid" : true,
  	"errors" : [ ],
  	"ok" : 1
  }
  

• In 2.8 mmapv1:

  {
  	"ns" : "test.foo",
  	"datasize" : 4800080,
  	"nrecords" : 100000,
  	"lastExtentSize" : 8388608,
  	"firstExtent" : "0:6000 ns:test.foo",
  	"lastExtent" : "0:550000 ns:test.foo",
  	"extentCount" : 6,
  	"extents" : [
  		{
  			"loc" : "0:6000",
  			"xnext" : "0:28000",
  			"xprev" : "null",
  			"nsdiag" : "test.foo",
  			"size" : 8192,
  			"firstRecord" : "0:60b0",
  			"lastRecord" : "0:7fb0"
  		},
  		{
  			"loc" : "0:28000",
  			"xnext" : "0:30000",
  			"xprev" : "0:6000",
  			"nsdiag" : "test.foo",
  			"size" : 32768,
  			"firstRecord" : "0:280b0",
  			"lastRecord" : "0:2ffb0"
  		},
  		{
  			"loc" : "0:30000",
  			"xnext" : "0:50000",
  			"xprev" : "0:28000",
  			"nsdiag" : "test.foo",
  			"size" : 131072,
  			"firstRecord" : "0:300b0",
  			"lastRecord" : "0:4ffb0"
  		},
  		{
  			"loc" : "0:50000",
  			"xnext" : "0:150000",
  			"xprev" : "0:30000",
  			"nsdiag" : "test.foo",
  			"size" : 524288,
  			"firstRecord" : "0:500b0",
  			"lastRecord" : "0:cffb0"
  		},
  		{
  			"loc" : "0:150000",
  			"xnext" : "0:550000",
  			"xprev" : "0:50000",
  			"nsdiag" : "test.foo",
  			"size" : 2097152,
  			"firstRecord" : "0:1500b0",
  			"lastRecord" : "0:34ffb0"
  		},
  		{
  			"loc" : "0:550000",
  			"xnext" : "null",
  			"xprev" : "0:150000",
  			"nsdiag" : "test.foo",
  			"size" : 8388608,
  			"firstRecord" : "0:5500b0",
  			"lastRecord" : "0:8c0c30"
  		}
  	],
  	"firstExtentDetails" : {
  		"loc" : "0:6000",
  		"xnext" : "0:28000",
  		"xprev" : "null",
  		"nsdiag" : "test.foo",
  		"size" : 8192,
  		"firstRecord" : "0:60b0",
  		"lastRecord" : "0:7fb0"
  	},
  	"lastExtentDetails" : {
  		"loc" : "0:550000",
  		"xnext" : "null",
  		"xprev" : "0:150000",
  		"nsdiag" : "test.foo",
  		"size" : 8388608,
  		"firstRecord" : "0:5500b0",
  		"lastRecord" : "0:8c0c30"
  	},
  	"objectsFound" : 100000,
  	"invalidObjects" : 0,
  	"nQuantizedSize" : 99995,
  	"bytesWithHeaders" : 6400080,
  	"bytesWithoutHeaders" : 4800080,
  	"bytesBson" : 3300000,
  	"deletedCount" : 1,
  	"deletedSize" : 4780944,
  	"delBucketSizes" : [
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		1,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0,
  		0
  	],
  	"nIndexes" : 1,
  	"keysPerIndex" : {
  		"test.foo.$_id_" : 100000
  	},
  	"indexDetails" : {
  		"test.foo.$_id_" : {
  			
  		}
  	},
  	"valid" : true,
  	"errors" : [ ],
  	"ok" : 1
  }