planCacheClear¶

Definition定义¶

planCacheClear¶

Removes cached query plans for a collection. Specify a query shape to remove cached query plans for that shape. Omit the query shape to clear all cached query plans.

The command has the following syntax:语法如下所示：

db.runCommand(
   {
      planCacheClear: <collection>,
      query: <query>,
      sort: <sort>,
      projection: <projection>,
      comment: <any>
   }
)

The planCacheClear command has the following field:

Field字段	Type类型	Description描述
query	document	Optional.可选。The query predicate of the query shape. Only the structure of the predicate, including the field names, are significant to the shape; the values in the query predicate are insignificant.
projection	document	Optional.可选。The projection associated with the query shape.
sort	document	Optional.可选。The sort associated with the query shape.
comment	any	Optional.可选。A user-provided comment to attach to this command. Once set, this comment appears alongside records of this command in the following locations: mongod log messages, in the attr.command.cursor.comment field. Database profiler output, in the command.comment field. currentOp output, in the command.comment field. A comment can be any valid BSON type (string, integer, object, array, etc). New in version 4.4.版本4.4中的新功能。

To see the query shapes for which cached query plans exist, see List Query Shapes.

Required Access¶

On systems running with authorization, a user must have access that includes the planCacheWrite action.

Examples示例¶

{
  "query" : { "qty" : { "$gt" : 10 } },
  "sort" : { "ord_date" : 1 },
  "projection" : { },
  "queryHash" : "9AAD95BE"  // Available starting in MongoDB 4.2
}

db.runCommand(
   {
      planCacheClear: "orders",
      query: { "qty" : { "$gt" : 10 } },
      sort: { "ord_date" : 1 }
   }
)

db.runCommand(
   {
      planCacheClear: "orders"
   }
)