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db.stats()

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Description描述

db.stats(scale)

Returns statistics that reflect the use state of a single database.返回反映单个数据库的使用状态的统计信息。

The db.stats() method is a wrapper around the dbStats database command.db.stats()方法是dbStats数据库命令的包装器。

Parameters参数

The db.stats() method has the following optional parameters:db.stats()方法具有以下可选参数：

Parameter参数Type类型Description描述
scalenumberOptional.可选的。The scale factor for the various size data. 各种大小数据的比例因子。The scale defaults to 1 to return size data in bytes. To display kilobytes rather than bytes, specify a scale value of 1024.scale数默认为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。
Starting in version 4.2, the output includes the scaleFactor used to scale the size values. 从4.2版本开始，输出包括用于缩放大小值的scaleFactor。
freeStoragenumberOptional.可选的。To return information on free space allocated to collections, set freeStorage to 1.要返回分配给集合的可用空间信息，请将freeStorage设置为1。
If the instance has a large number of collections or indexes, obtaining free space usage data may cause processing delays. 如果实例具有大量集合或索引，则获取可用空间使用情况数据可能会导致处理延迟。To gather db.stats() data without free space details, either set freeStorage to 0 or do not include the parameter. 要集合没有可用空间详细信息的db.stats()数据，请将freeStorage设置为0或不包括该参数。

Output输出

The db.stats() method returns a document with statistics about the database system's state. db.stats()方法返回一个文档，其中包含有关数据库系统状态的统计信息。A complete listing, including freeStorage details, resembles the following:包括freeStorage详细信息在内的完整列表如下所示：

{
  db: 'test',
  collections: 2,
  views: 0,
  objects: 1689,
  avgObjSize: 52.56542332741267,
  dataSize: 86.7021484375,
  storageSize: 100,
  freeStorageSize: 32,
  indexes: 2,
  indexSize: 116,
  indexFreeStorageSize: 36,
  totalSize: 216,
  totalFreeStorageSize: 68,
  scaleFactor: 1024,
  fsUsedSize: 60155820,
  fsTotalSize: 61255492,
  ok: 1,
  '$clusterTime': {
    clusterTime: Timestamp({ t: 1646085664, i: 1 }),
    signature: {
      hash: Binary(Buffer.from("0000000000000000000000000000000000000000", "hex"), 0),
      keyId: Long("0")
    }
  },
  operationTime: Timestamp({ t: 1646085664, i: 1 })
}

For an explanation of the output, see Output.有关输出的说明，请参阅输出。

Behavior行为

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, count and size statistics reported by db.stats() may be inaccurate.在使用Wired Tiger存储引擎不干净地关闭mongod之后，db.stats()报告的计数和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. 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。Checkpoints usually occur every 60 seconds. 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：

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, dbStats operations require the member to be in PRIMARY or SECONDARY state. 从MongoDB 4.4开始，要在副本集成员上运行，dbStats操作要求该成员处于PRIMARY或SECONDARY状态。If the member is in another state, such as STARTUP2, the operation errors.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。

Examples实例

Scale Output Values缩放输出值

To to return values in kilobytes, set the scale to 1024:要返回以千字节为单位的值，请将scale设置为1024：

db.stats(1024)
Note

The scale factor rounds values to whole numbers.比例因子将值四舍五入为整数。

Return a Single Value返回单个值

To return a single value, such as indexSize, append the field name to db.stats().要返回单个值，如indexSize，请将字段名附加到db.stat()中。

db.stats().indexSize
db.stats(1024).indexSize

The output shows the difference between the original and scaled values.输出显示原始值和缩放值之间的差异。

118784
116

Return Information on Free Space Allocated to Collections返回分配给集合的可用空间信息

To return information on free space allocated to collections, pass the freeStorage parameter to db.stats().要返回分配给集合的可用空间信息，请将freeStorage参数传递给db.stat()。

The following example returns the indexFreeStorageSize in kilobytes:以下示例以千字节为单位返回indexFreeStorageSize：

db.stats( { freeStorage: 1, scale: 1024 } ).indexFreeStorageSize