Mongo db version v4.2.17
Here are my execution stats:
execution stats
`> db.getCollection("test").explain("executionStats").aggregate([ { $match: { endTime: { $gt: new Date(1686355200000) } } },{ $group: { _id: "$contextId" }}, { $project: { contextId: "$_id", _id: 0 } }], {"allowDiskUse" : true})
{
"stages" : [
{
"$cursor" : {
"query" : {
"endTime" : {
"$gt" : ISODate("2023-06-10T00:00:00Z")
}
},
"fields" : {
"contextId" : 1,
"_id" : 0
},
"queryPlanner" : {
"plannerVersion" : 1,
"namespace" : "mydb.test",
"indexFilterSet" : false,
"parsedQuery" : {
"endTime" : {
"$gt" : ISODate("2023-06-10T00:00:00Z")
}
},
"queryHash" : "96AD493D",
"planCacheKey" : "5A080EEB",
"winningPlan" : {
"stage" : "FETCH",
"inputStage" : {
"stage" : "IXSCAN",
"keyPattern" : {
"endTime" : 1
},
"indexName" : "end",
"isMultiKey" : false,
"multiKeyPaths" : {
"endTime" : [ ]
},
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 2,
"direction" : "forward",
"indexBounds" : {
"endTime" : [
"(new Date(1686355200000), new Date(9223372036854775807)]"
]
}
}
},
"rejectedPlans" : [ ]
},
"executionStats" : {
"executionSuccess" : true,
"nReturned" : 10227381,
"executionTimeMillis" : 91474,
"totalKeysExamined" : 10227381,
"totalDocsExamined" : 10227381,
"executionStages" : {
"stage" : "FETCH",
"nReturned" : 10227381,
"executionTimeMillisEstimate" : 3196,
"works" : 10227382,
"advanced" : 10227381,
"needTime" : 0,
"needYield" : 0,
"saveState" : 80872,
"restoreState" : 80872,
"isEOF" : 1,
"docsExamined" : 10227381,
"alreadyHasObj" : 0,
"inputStage" : {
"stage" : "IXSCAN",
"nReturned" : 10227381,
"executionTimeMillisEstimate" : 1560,
"works" : 10227382,
"advanced" : 10227381,
"needTime" : 0,
"needYield" : 0,
"saveState" : 80872,
"restoreState" : 80872,
"isEOF" : 1,
"keyPattern" : {
"endTime" : 1
},
"indexName" : "end",
"isMultiKey" : false,
"multiKeyPaths" : {
"endTime" : [ ]
},
"isUnique" : false,
"isSparse" : false,
"isPartial" : false,
"indexVersion" : 2,
"direction" : "forward",
"indexBounds" : {
"endTime" : [
"(new Date(1686355200000), new Date(9223372036854775807)]"
]
},
"keysExamined" : 10227381,
"seeks" : 1,
"dupsTested" : 0,
"dupsDropped" : 0
}
}
}
}
},
{
"$group" : {
"_id" : "$contextId"
}
},
{
"$project" : {
"_id" : false,
"contextId" : "$_id"
}
}
],
"serverInfo" : {
"host" : "MY-DB-HOST",
"port" : 27017,
"version" : "4.2.17",
"gitVersion" : "be089838c55d33b6f6039c4219896ee4a3cd704f"
},
"ok" : 1
}
>
`
and my collection stats
`db.getCollection("test").stats()
{
"ns" : "mydb.test",
"size" : 4002064919,
"count" : 10227409,
"avgObjSize" : 391,
"storageSize" : 1337253888,
"capped" : false,
"wiredTiger" : {
"metadata" : {
"formatVersion" : 1
},
"creationString" : "access_pattern_hint=none,allocation_size=4KB,app_metadata=(formatVersion=1),assert=(commit_timestamp=none,durable_timestamp=none,read_timestamp=none),block_allocation=best,block_compressor=snappy,cache_resident=false,checksum=on,colgroups=,collator=,columns=,dictionary=0,encryption=(keyid=,name=),exclusive=false,extractor=,format=btree,huffman_key=,huffman_value=,ignore_in_memory_cache_size=false,immutable=false,internal_item_max=0,internal_key_max=0,internal_key_truncate=true,internal_page_max=4KB,key_format=q,key_gap=10,leaf_item_max=0,leaf_key_max=0,leaf_page_max=32KB,leaf_value_max=64MB,log=(enabled=true),lsm=(auto_throttle=true,bloom=true,bloom_bit_count=16,bloom_config=,bloom_hash_count=8,bloom_oldest=false,chunk_count_limit=0,chunk_max=5GB,chunk_size=10MB,merge_custom=(prefix=,start_generation=0,suffix=),merge_max=15,merge_min=0),memory_page_image_max=0,memory_page_max=10m,os_cache_dirty_max=0,os_cache_max=0,prefix_compression=false,prefix_compression_min=4,source=,split_deepen_min_child=0,split_deepen_per_child=0,split_pct=90,type=file,value_format=u",
"type" : "file",
"uri" : "statistics:table:collection-1560--5498070625033782530",
"LSM" : {
"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,
"bloom filters in the LSM tree" : 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 checkpoint throttle" : 0,
"sleep for LSM merge throttle" : 0,
"total size of bloom filters" : 0
},
"block-manager" : {
"allocations requiring file extension" : 0,
"blocks allocated" : 1960,
"blocks freed" : 1122,
"checkpoint size" : 710680576,
"file allocation unit size" : 4096,
"file bytes available for reuse" : 626548736,
"file magic number" : 120897,
"file major version number" : 1,
"file size in bytes" : 1337253888,
"minor version number" : 0
},
"btree" : {
"btree checkpoint generation" : 323,
"btree clean tree checkpoint expiration time" : NumberLong("9223372036854775807"),
"column-store fixed-size leaf pages" : 0,
"column-store internal pages" : 0,
"column-store variable-size RLE encoded values" : 0,
"column-store variable-size deleted values" : 0,
"column-store variable-size leaf pages" : 0,
"fixed-record size" : 0,
"maximum internal page key size" : 368,
"maximum internal page size" : 4096,
"maximum leaf page key size" : 2867,
"maximum leaf page size" : 32768,
"maximum leaf page value size" : 67108864,
"maximum tree depth" : 5,
"number of key/value pairs" : 0,
"overflow pages" : 0,
"pages rewritten by compaction" : 0,
"row-store empty values" : 0,
"row-store internal pages" : 0,
"row-store leaf pages" : 0
},
"cache" : {
"bytes currently in the cache" : 4519654858,
"bytes dirty in the cache cumulative" : 131064624,
"bytes read into cache" : 10085864857,
"bytes written from cache" : 178306687,
"checkpoint blocked page eviction" : 0,
"data source pages selected for eviction unable to be evicted" : 114,
"eviction walk passes of a file" : 19408,
"eviction walk target pages histogram - 0-9" : 7309,
"eviction walk target pages histogram - 10-31" : 9991,
"eviction walk target pages histogram - 128 and higher" : 0,
"eviction walk target pages histogram - 32-63" : 2108,
"eviction walk target pages histogram - 64-128" : 0,
"eviction walks abandoned" : 1811,
"eviction walks gave up because they restarted their walk twice" : 3062,
"eviction walks gave up because they saw too many pages and found no candidates" : 2340,
"eviction walks gave up because they saw too many pages and found too few candidates" : 233,
"eviction walks reached end of tree" : 9774,
"eviction walks started from root of tree" : 7451,
"eviction walks started from saved location in tree" : 11957,
"hazard pointer blocked page eviction" : 6,
"in-memory page passed criteria to be split" : 18,
"in-memory page splits" : 9,
"internal pages evicted" : 2752,
"internal pages split during eviction" : 0,
"leaf pages split during eviction" : 10,
"modified pages evicted" : 10,
"overflow pages read into cache" : 0,
"page split during eviction deepened the tree" : 0,
"page written requiring cache overflow records" : 0,
"pages read into cache" : 88141,
"pages read into cache after truncate" : 0,
"pages read into cache after truncate in prepare state" : 0,
"pages read into cache requiring cache overflow entries" : 0,
"pages requested from the cache" : 27656375,
"pages seen by eviction walk" : 422674,
"pages written from cache" : 1798,
"pages written requiring in-memory restoration" : 0,
"tracked dirty bytes in the cache" : 1483332,
"unmodified pages evicted" : 53517
},
"cache_walk" : {
"Average difference between current eviction generation when the page was last considered" : 0,
"Average on-disk page image size seen" : 0,
"Average time in cache for pages that have been visited by the eviction server" : 0,
"Average time in cache for pages that have not been visited by the eviction server" : 0,
"Clean pages currently in cache" : 0,
"Current eviction generation" : 0,
"Dirty pages currently in cache" : 0,
"Entries in the root page" : 0,
"Internal pages currently in cache" : 0,
"Leaf pages currently in cache" : 0,
"Maximum difference between current eviction generation when the page was last considered" : 0,
"Maximum page size seen" : 0,
"Minimum on-disk page image size seen" : 0,
"Number of pages never visited by eviction server" : 0,
"On-disk page image sizes smaller than a single allocation unit" : 0,
"Pages created in memory and never written" : 0,
"Pages currently queued for eviction" : 0,
"Pages that could not be queued for eviction" : 0,
"Refs skipped during cache traversal" : 0,
"Size of the root page" : 0,
"Total number of pages currently in cache" : 0
},
"compression" : {
"compressed page maximum internal page size prior to compression" : 4096,
"compressed page maximum leaf page size prior to compression " : 131072,
"compressed pages read" : 85133,
"compressed pages written" : 1551,
"page written failed to compress" : 0,
"page written was too small to compress" : 247
},
"cursor" : {
"bulk loaded cursor insert calls" : 0,
"cache cursors reuse count" : 177959,
"close calls that result in cache" : 0,
"create calls" : 22,
"insert calls" : 172003,
"insert key and value bytes" : 68688868,
"modify" : 0,
"modify key and value bytes affected" : 0,
"modify value bytes modified" : 0,
"next calls" : 202,
"open cursor count" : 1,
"operation restarted" : 0,
"prev calls" : 1,
"remove calls" : 1093,
"remove key bytes removed" : 5465,
"reserve calls" : 0,
"reset calls" : 6710744,
"search calls" : 803663619,
"search near calls" : 0,
"truncate calls" : 0,
"update calls" : 0,
"update key and value bytes" : 0,
"update value size change" : 0
},
"reconciliation" : {
"dictionary matches" : 0,
"fast-path pages deleted" : 0,
"internal page key bytes discarded using suffix compression" : 2404,
"internal page multi-block writes" : 5,
"internal-page overflow keys" : 0,
"leaf page key bytes discarded using prefix compression" : 0,
"leaf page multi-block writes" : 15,
"leaf-page overflow keys" : 0,
"maximum blocks required for a page" : 1,
"overflow values written" : 0,
"page checksum matches" : 144,
"page reconciliation calls" : 1211,
"page reconciliation calls for eviction" : 3,
"pages deleted" : 1
},
"session" : {
"object compaction" : 0
},
"transaction" : {
"update conflicts" : 0
}
},
"nindexes" : 5,
"indexBuilds" : [ ],
"totalIndexSize" : 2992058368,
"indexSizes" : {
"_id_" : 224673792,
"sessionEnd" : 125272064,
"end" : 86822912,
"sessionCtxEnd" : 1283137536,
"ctxEnd" : 1272152064
},
"scaleFactor" : 1,
"ok" : 1
}
Thanks !