Docs Home → MongoDB Manual

collStats

On this page本页内容

Definition定义

collStats

Deprecated since version 6.2.自版本6.2以来已弃用。

In versions 6.2 and later use the $collStats aggregation stage.在6.2及更高版本中，使用$collStats聚合阶段。

The collStats command returns a variety of storage statistics for a given collection.collStats命令返回给定集合的各种存储统计信息。

Use the $collStats aggregation stage instead of the collStats command and its mongosh helper method db.collection.stats().使用$collStats聚合阶段，而不是collStats命令及其mongosh辅助方法db.collection.stats()。

Tip

In mongosh, this command can also be run through the stats() helper method. 在mongosh中，这个命令也可以通过stats()助手方法运行。Specific fields in the collStats output can be accessed using the dataSize(), estimatedDocumentCount(), isCapped(), latencyStats(), storageSize(), totalIndexSize(), and totalSize() helper methods.collStats输出中的特定字段可以使用dataSize()、estimatedDocumentCount()、isCapped()、latencyStats()、storageSize()、totalIndexSize()和totalSize()辅助方法访问。

Helper methods are convenient for mongosh users, but they may not return the same level of information as database commands. In cases where the convenience is not needed or the additional return fields are required, use the database command.助手方法对mongosh用户来说很方便，但它们可能不会返回与数据库命令相同级别的信息。如果不需要方便，或者需要额外的返回字段，请使用数据库命令。

To run collStats, use the db.runCommand( { <command> } ) method.要运行collStats，请使用db.runCommand( { <command> } )方法。

Syntax语法

The command has the following syntax:该命令具有以下语法：

db.runCommand(
   {
     collStats: <string>,
     scale: <int>
   }
)

Command Fields命令字段

The command takes the following fields:该命令包含以下字段：

Field字段Type类型Description描述
collStatsstringThe name of the target collection.目标集合的名称。
scaleintOptional.可选的。The scale factor for the various size data (with the exception of those sizes that specify the unit of measurement in the field name). 各种尺寸数据的比例因子（在字段名称中指定测量单位的尺寸除外）。The value defaults to 1 to return size data in bytes. To display kilobytes rather than bytes, specify a scale value of 1024.该值默认为1，以返回以字节为单位的大小数据。若要显示千字节而不是字节，请指定1024的scale值。
If you specify a non-integer scale factor, MongoDB uses the integer part of the specified factor. 如果指定非整数比例因子，MongoDB将使用指定因子的整数部分。For example, if you specify a scale factor of 1023.999, MongoDB uses 1023 as the scale factor.例如，如果指定的比例因子为1023.999，MongoDB将使用1023作为比例因子。
The scale factor rounds the affected size values to whole numbers. 比例因子将受影响的大小值四舍五入为整数。

Behavior行为

Redaction修改

When using Queryable Encryption, $collStats output redacts certain information for encrypted collections:使用可查询加密时，$collStats输出会对加密集合的某些信息进行编辑：

  • The output omits 输出省略"queryExecStats"
  • The output omits 输出省略"latencyStats"
  • The output redacts "WiredTiger", if present, to include only the url field.输出对"WiredTiger"（如果存在）进行编辑，以仅包括url字段。

Scaled Sizes缩放尺寸

Unless otherwise specified by the metric name (such as "bytes currently in the cache"), values related to size are displayed in bytes and can be overridden by scale.除非度量名称另有规定（例如“缓存中当前的字节数”），否则与大小相关的值以字节为单位显示，并且可以按比例覆盖。

The scale factor rounds the affected size values to whole numbers.比例因子将受影响的大小值四舍五入为整数。

Accuracy after Unexpected Shutdown意外停机后的准确性

After an unclean shutdown of a mongod using the Wired Tiger storage engine, size statistics reported by collStats may be inaccurate.在使用Wired Tiger存储引擎不干净地关闭mongod之后，collStats报告的大小统计数据可能不准确。

The amount of drift depends on the number of insert, update, or delete operations performed between the last checkpoint and the unclean shutdown. Checkpoints usually occur every 60 seconds. 漂移量取决于在最后一个检查点和非干净关闭之间执行的插入、更新或删除操作的数量。检查点通常每60秒出现一次。However, mongod instances running with non-default --syncdelay settings may have more or less frequent checkpoints.然而，使用非默认--syncdelay设置运行的mongod实例可能或多或少有频繁的检查点。

Run validate on each collection on the mongod to restore statistics after an unclean shutdown.对mongod上的每个集合运行validate，以在不干净的关闭后恢复统计信息。

After an unclean shutdown:不干净关机后：

In-Progress Indexes进行中索引

collStats includes information on indexes currently being built. 包括有关当前正在生成的索引的信息。For details, see:有关详细信息，请参阅：

Replica Set Member State Restriction副本集成员状态限制

Starting in MongoDB 4.4, to run on a replica set member, collStats operations require the member to be in PRIMARY or SECONDARY state. If the member is in another state, such as STARTUP2, the operation errors.从MongoDB 4.4开始，要在副本集成员上运行，collStats操作要求该成员处于PRIMARY或SECONDARY状态。如果成员处于其他状态，例如STARTUP2，则操作将出错。

In previous versions, the operations also run when the member is in STARTUP2. The operations wait until the member transitioned to RECOVERING.在以前的版本中，成员处于STARTUP2时也会运行这些操作。操作将等待，直到成员转换到RECOVERING。

Non-Existent Collections不存在的集合

If you run collStats for a non-existent collection, then depending on your database implementation, collStats might return 0 values in the output fields instead of returning an error.如果对不存在的集合运行collStats，那么根据数据库实现的不同，collStat可能会在输出字段中返回0值，而不是返回错误。

For example:例如：

db.runCommand( { collStats : "nonExistentCollection" } )

Example output with 0 values in the fields:字段中包含0值的输出示例：

{
   ns: 'test.nonExistentCollection',
   size: 0,
   count: 0,
   ...
}

Example实例

The following operation runs the collStats command on the restaurants collection, specifying a scale of 1024 bytes:以下操作在restaurants集合上运行collStats命令，指定1024字节的小数位数：

db.runCommand( { collStats : "restaurants", scale: 1024 } )

The following document provides a representation of the collStats output. 以下文档提供了collStats输出的表示形式。Depending on the configuration of your collection and the storage engine, the output fields may vary.根据集合和存储引擎的配置，输出字段可能会有所不同。

{
  "ns" : <string>,
  "size" : <number>,
  "timeseries" : {
     "bucketsNs" : <bucketName>,
     "bucketCount" : <number>,
     "avgBucketSize" : <number>,
     "numBucketInserts" : <number>,
     "numBucketUpdates" : <number>,
     "numBucketsOpenedDueToMetadata" : <number>,
     "numBucketsClosedDueToCount" : <number>,
     "numBucketsClosedDueToSize" : <number>,
     "numBucketsClosedDueToTimeForward" : <number>,
     "numBucketsClosedDueToTimeBackward" : <number>,
     "numBucketsClosedDueToMemoryThreshold" : <number>,
     "numCommits" : <number>,
     "numWaits" : <number>,
     "numMeasurementsCommitted" : <number>,
     "avgNumMeasurementsPerCommit": <number>
  },
  "count" : <number>,
  "avgObjSize" : <number>,
  "numOrphanDocs" : <number>,      // Available starting in MongoDB 6.0
  "storageSize" : <number>,
  "freeStorageSize" : <number>,
  "capped" : <boolean>,
  "max" : <number>,
  "maxSize" :  <number>,
  "wiredTiger" : {
     "metadata" : {
        "formatVersion" : <num>
     },
     "creationString" : <string>
     "type" :  <string>,
     "uri" :  <string>,
     "LSM" : {
        "bloom filter false positives" : <number>,
        "bloom filter hits" : <number>,
        "bloom filter misses" : <number>,
        "bloom filter pages evicted from cache" : <number>,
        "bloom filter pages read into cache" : <number>,
        "bloom filters in the LSM tree" : <number>,
        "total size of bloom filters" : <number>,
        "chunks in the LSM tree" : <number>,
        "highest merge generation in the LSM tree" : <number>,
        "queries that could have benefited from a Bloom filter that did not exist" : <number>,
        "sleep for LSM checkpoint throttle" : <number>,
        "sleep for LSM merge throttle" : <number>
        "total size of bloom filters" : <number>
     },
     "block-manager" : {
         "allocations requiring file extension" : <number>,
         "blocks allocated" : <number>,
         "blocks freed" : <number>,
         "checkpoint size" : <number>,
         "file allocation unit size" : <number>,
         "file bytes available for reuse" : <number>,
         "file magic number" : <number>,
         "file major version number" : <number>,
         "file size in bytes" : <number>,
         "minor version number" : <number>
     },
     "btree" : {
         "btree checkpoint generation" : <number>,
         "column-store fixed-size leaf pages" : <number>,
         "column-store internal pages" : <number>,
         "column-store variable-size RLE encoded values" : <number>,
         "column-store variable-size deleted values" : <number>,
         "column-store variable-size leaf pages" : <number>,
         "fixed-record size" : <number>,
         "maximum internal page key size" : <number>,
         "maximum internal page size" : <number>,
         "maximum leaf page key size" : <number>,
         "maximum leaf page size" : <number>,
         "maximum leaf page value size" : <number>,
         "maximum tree depth" : <number>,
         "number of key/value pairs" : <number>,
         "overflow pages" : <number>,
         "pages rewritten by compaction" : <number>,
         "row-store empty values" : <number>,
         "row-store internal pages" : <number>,
         "row-store leaf pages" : <number>
     },
     "cache" : {
        "bytes currently in the cache" : <number>,
        "bytes dirty in the cache cumulative" : <number>,
        "bytes read into cache" : <number>,
        "bytes written from cache" : <number>,
        "checkpoint blocked page eviction" : <number>,
        "data source pages selected for eviction unable to be evicted" : <number>,
        "eviction walk passes of a file" : <number>,
        "eviction walk target pages histogram - 0-9" : <number>,
        "eviction walk target pages histogram - 10-31" : <number>,
        "eviction walk target pages histogram - 128 and higher" : <number>,
        "eviction walk target pages histogram - 32-63" : <number>,
        "eviction walk target pages histogram - 64-128" : <number>,
        "eviction walks abandoned" : <number>,
        "eviction walks gave up because they restarted their walk twice" : <number>,
        "eviction walks gave up because they saw too many pages and found no candidates" : <number>,
        "eviction walks gave up because they saw too many pages and found too few candidates" : <number>,
        "eviction walks reached end of tree" : <number>,
        "eviction walks started from root of tree" : <number>,
        "eviction walks started from saved location in tree" : <number>,
        "hazard pointer blocked page eviction" : <number>,
        "in-memory page passed criteria to be split" : <number>,
        "in-memory page splits" : <number>,
        "internal pages evicted" : <number>,
        "internal pages split during eviction" : <number>,
        "leaf pages split during eviction" : <number>,
        "modified pages evicted" : <number>,
        "overflow pages read into cache" : <number>,
        "page split during eviction deepened the tree" : <number>,
        "page written requiring cache overflow records" : <number>,
        "pages read into cache" : <number>,
        "pages read into cache after truncate" : <number>,
        "pages read into cache after truncate in prepare state" : <number>,
        "pages read into cache requiring cache overflow entries" : <number>,
        "pages requested from the cache" : <number>,
        "pages seen by eviction walk" : <number>,
        "pages written from cache" : <number>,
        "pages written requiring in-memory restoration" : <number>,
        "tracked dirty bytes in the cache" : <number>,
        "unmodified pages evicted" : <number>
     },
     "cache_walk" : {
        "Average difference between current eviction generation when the page was last considered" : <number>,
        "Average on-disk page image size seen" : <number>,
        "Average time in cache for pages that have been visited by the eviction server" : <number>,
        "Average time in cache for pages that have not been visited by the eviction server" : <number>,
        "Clean pages currently in cache" : <number>,
        "Current eviction generation" : <number>,
        "Dirty pages currently in cache" : <number>,
        "Entries in the root page" : <number>,
        "Internal pages currently in cache" : <number>,
        "Leaf pages currently in cache" : <number>,
        "Maximum difference between current eviction generation when the page was last considered" : <number>,
        "Maximum page size seen" : <number>,
        "Minimum on-disk page image size seen" : <number>,
        "Number of pages never visited by eviction server" : <number>,
        "On-disk page image sizes smaller than a single allocation unit" : <number>,
        "Pages created in memory and never written" : <number>,
        "Pages currently queued for eviction" : <number>,
        "Pages that could not be queued for eviction" : <number>,
        "Refs skipped during cache traversal" : <number>,
        "Size of the root page" : <number>,
        "Total number of pages currently in cache" : <number>
     },
     "compression" : {
        "compressed page maximum internal page size prior to compression" : <number>,
        "compressed page maximum leaf page size prior to compression " : <number>,
        "compressed pages read" : <number>,
        "compressed pages written" : <number>,
        "page written failed to compress" : <number>,
        "page written was too small to compress" : 1
     },
     "cursor" : {
        "bulk loaded cursor insert calls" : <number>,
        "cache cursors reuse count" : <number>,
        "close calls that result in cache" : <number>,
        "create calls" : <number>,
        "insert calls" : <number>,
        "insert key and value bytes" : <number>,
        "modify" : <number>,
        "modify key and value bytes affected" : <number>,
        "modify value bytes modified" : <number>,
        "next calls" : <number>,
        "open cursor count" : <number>,
        "operation restarted" : <number>,
        "prev calls" : <number>,
        "remove calls" : <number>,
        "remove key bytes removed" : <number>,
        "reserve calls" : <number>,
        "reset calls" : <number>,
        "search calls" : <number>,
        "search near calls" : <number>,
        "truncate calls" : <number>,
        "update calls" : <number>,
        "update key and value bytes" : <number>,
        "update value size change" : <num>
     },
     "reconciliation" : {
        "dictionary matches" : <number>,
        "fast-path pages deleted" : <number>,
        "internal page key bytes discarded using suffix compression" : <number>,
        "internal page multi-block writes" : <number>,
        "internal-page overflow keys" : <number>,
        "leaf page key bytes discarded using prefix compression" : <number>,
        "leaf page multi-block writes" : <number>,
        "leaf-page overflow keys" : <number>,
        "maximum blocks required for a page" : <number>,
        "overflow values written" : <number>,
        "page checksum matches" : <number>,
        "page reconciliation calls" : <number>,
        "page reconciliation calls for eviction" : <number>,
        "pages deleted" : <number>
     },
     "session" : {
        "object compaction" : <number>,
     },
     "transaction" : {
        "update conflicts" : <number>
     }
  },
  "nindexes" : <number>,
  "indexDetails" : {
     "_id_" : {
        "metadata" : {
           "formatVersion" : <number>
        },
        ...
     },
     ...
  },
  "indexBuilds" : [
     <string>,
  ],
  "totalIndexSize" : <number>,
  "totalSize" : <number>,      // Available starting in MongoDB 4.4
  "indexSizes" : {
          "_id_" : <number>,
          "<indexName>" : <number>,
          ...
  },
  "scaleFactor" : <number>
  "ok" : <number>
}

Output输出

collStats.ns

The namespace of the current collection, which follows the format [database].[collection].当前集合的命名空间，其格式为[database].[collection]。

collStats.size

The total uncompressed size in memory of all records in a collection. The size does not include the size of any indexes associated with the collection, which the totalIndexSize field reports.集合中所有记录在内存中的未压缩总大小。size不包括totalIndexSize字段报告的与集合关联的任何索引的大小。

The scale argument affects this value. Data compression does not affect this value.scale参数会影响此值。数据压缩不会影响此值。

collStats.timeseries

timeseries appears when you run the collStats command on a time series collection.在时间序列集合上运行collStats命令时显示。

This document contains data for internal diagnostic use.本文档包含用于内部诊断的数据。

collStats.count

The number of objects or documents in this collection.此集合中对象或文档的数目。

collStats.avgObjSize

The average size of an object in the collection. 集合中对象的平均大小。The scale argument does not affect this value.scale参数不影响此值。

collStats.numOrphanDocs

The number of orphaned documents in the collection.集合中孤立文档的数量。

New in version 6.0. 6.0版新增。

collStats.storageSize

The total amount of storage allocated to this collection for document storage. 分配给此集合用于文档存储的存储总量。The scale argument affects this value.scale参数会影响此值。

If collection data is compressed (which is the default for WiredTiger), the storage size reflects the compressed size and may be smaller than the value for collStats.size.如果采集数据被压缩（这是WiredTiger的默认值），则存储大小会反映压缩后的大小，并且可能小于collStats.size的值。

storageSize does not include index size. See totalIndexSize for index sizing.不包括索引大小。请参阅totalIndexSize了解索引大小。

collStats.freeStorageSize

Unavailable for the In-Memory Storage Engine内存存储引擎不可用

The amount of storage available for reuse. 可重复使用的存储量。The scale argument affects this value.scale参数会影响此值。

The field is only available if storage is available for reuse (i.e. greater than zero).只有当存储可重复使用（即大于零）时，该字段才可用。

New in version 4.4. 4.4版新增。

collStats.nindexes

The number of indexes on the collection. All collections have at least one index on the _id field.集合上的索引数。所有集合在_id字段上至少有一个索引。

nindexes includes indexes currently being built in its count.在其计数中包括当前正在生成的索引。

collStats.indexDetails

A document that reports data from the WiredTiger storage engine for each index in the collection. Other storage engines will return an empty document.为集合中的每个索引报告WiredTiger存储引擎数据的文档。其他存储引擎将返回一个空文档。

The fields in this document are the names of the indexes, while the values themselves are documents that contain statistics for the index provided by the storage engine. These statistics are for internal diagnostic use.此文档中的字段是索引的名称，而值本身是包含存储引擎提供的索引统计信息的文档。这些统计数据用于内部诊断。

indexDetails includes details on indexes currently being built.包括当前正在生成的索引的详细信息。

collStats.indexBuilds

An array that contains the names of the indexes that are currently being built on the collection. 一个数组，包含当前正在集合上生成的索引的名称。Once an index build completes, the index does not appear in the indexBuilds.一旦索引生成完成，该索引就不会出现在indexBuilds中。

collStats.totalIndexSize

Sum of the disk space used by all indexes. The scale argument affects this value.所有索引使用的磁盘空间的总和。scale参数会影响此值。

If an index uses prefix compression (which is the default for WiredTiger), the returned size reflects the compressed size for any such indexes when calculating the total.如果索引使用前缀压缩（这是WiredTiger的默认值），则在计算总数时，返回的大小反映任何此类索引的压缩大小。

totalIndexSize includes indexes currently being built in the total size.在总大小中包括当前正在生成的索引。

collStats.totalSize

The sum of the storageSize and totalIndexSize. The scale argument affects this value.storageSize和totalIndexSize的总和。scale参数会影响此值。

New in version 4.4. 4.4版新增。

collStats.indexSizes

This field specifies the key and size of every existing index on the collection. 此字段指定集合上每个现有索引的键和大小。The scale argument affects this value.scale参数会影响此值。

If an index uses prefix compression (which is the default for WiredTiger), the returned size reflects the compressed size.如果索引使用前缀压缩（这是WiredTiger的默认值），则返回的大小反映压缩后的大小。

indexSizes includes the sizes of indexes currently being built.包括当前正在生成的索引的大小。

collStats.scaleFactor

The scale value used by the command.命令使用的scale值。

If you had specified a non-integer scale factor, MongoDB uses the integer part of the specified factor. 如果您指定了一个非整数比例因子，MongoDB将使用指定因子的整数部分。For example, if you specify a scale factor of 1023.999, MongoDB uses 1023 as the scale factor.例如，如果指定的比例因子为1023.999，MongoDB将使用1023作为比例因子。

collStats.capped

This field will be "true" if the collection is capped.如果集合封顶集合，则此字段为“true”。

collStats.max

Shows the maximum number of documents that may be present in a capped collection.显示封顶集合中可能存在的最大文档数。

collStats.maxSize

Shows the maximum size of a capped collection.显示封顶集合的最大大小。

collStats.wiredTiger

wiredTiger only appears when using the WiredTiger storage engine. 仅在使用WiredTiger存储引擎时显示。When using Queryable Encryption, WiredTiger data is redacted to only the url field.使用可查询加密时，WiredTiger数据将被编辑为仅url字段。

This document contains data reported directly by the WiredTiger engine and other data for internal diagnostic use.本文档包含WiredTiger引擎直接报告的数据以及用于内部诊断的其他数据。

collStats.inMemory

inMemory only appears when using the in-memory storage engine.仅在使用内存中存储引擎时显示。

This document contains data reported directly by the storage engine and other data for internal diagnostic use.本文档包含存储引擎直接报告的数据以及供内部诊断使用的其他数据。