Definition定义
db.collection.dropIndexes()Drops the specified index or indexes (except the index on the从集合中删除指定的一个或多个索引(_idfield and the last remaining shard key index) from a collection._id字段上的索引和最后一个剩余的分片键索引除外)。You can use the method to:您可以使用该方法:Drop all but the从集合中删除除_idindex from a collection._id索引之外的所有索引。db.collection.dropIndexes()Drop a specified index from a collection. To specify the index, you can pass the method either:从集合中删除指定的索引。要指定索引,您可以传递以下方法之一:The index specification document (unless the index is a text index in which case, use the index name to drop):索引规范文档(除非索引是text索引,在这种情况下,请使用索引名称删除):db.collection.dropIndexes( { a: 1, b: 1 } )The index name:索引名称:db.collection.dropIndexes( "a_1_b_1" )Tip
To get the names of the indexes, use the要获取索引的名称,请使用db.collection.getIndexes()method.db.collection.getIndexes()方法。
Drop specified indexes from a collection. To specify multiple indexes to drop, pass the method an array of index names:从集合中删除指定的索引。要指定要删除的多个索引,请向该方法传递一个索引名称数组:db.collection.dropIndexes( [ "a_1_b_1", "a_1", "a_1__id_-1" ] )If the array of index names includes a non-existent index, the method errors without dropping any of the specified indexes.如果索引名称数组包含不存在的索引,则该方法会出错,但不会删除任何指定的索引。Tip
To get the names of the indexes, use the要获取索引的名称,请使用db.collection.getIndexes()method.db.collection.getIndexes()方法。
Thedb.collection.dropIndexes()method takes the following optional parameter:db.collection.dropIndexes()方法接受以下可选参数:Parameter参数Type类型Description描述indexesstring or document or array of strings字符串、文档或字符串数组Optional.可选。Specifies the index or indexes to drop.指定要删除的索引。To drop all but the _id index from the collection, omit the parameter.要从集合中删除除_id索引之外的所有索引,请省略该参数。To drop a single index, specify either the index name, the index specification document (unless the index is a text index), or an array of the index name.要删除单个索引,请指定索引名称、索引规范文档(除非索引是text索引)或索引名称的数组。To drop a text index, specify the index name or an array of the index name instead of the index specification document.要删除text索引,请指定索引名称或索引名称的数组,而不是索引规范文档。To drop multiple indexes, specify an array of the index names.若要删除多个索引,请指定一个索引名称数组。
Compatibility兼容性
This method is available in deployments hosted in the following environments:此方法在以下环境中托管的部署中可用:
- MongoDB Atlas
: The fully managed service for MongoDB deployments in the cloud:云中MongoDB部署的完全托管服务
Note
This command is supported in all MongoDB Atlas clusters. For information on Atlas support for all commands, see Unsupported Commands.所有MongoDB Atlas集群都支持此命令。有关Atlas支持所有命令的信息,请参阅不支持的命令。
- MongoDB Enterprise
: The subscription-based, self-managed version of MongoDB:MongoDB的基于订阅的自我管理版本 - MongoDB Community
: The source-available, free-to-use, and self-managed version of MongoDB:MongoDB的源代码可用、免费使用和自我管理版本
Behavior行为
Starting in MongoDB 6.0, 从MongoDB 6.0开始,如果您试图使用db.collection.dropIndexes() raises an error if you attempt to use it to remove the last remaining shard key compatible index. db.collection.dropIndexes()删除最后一个剩余的分片键兼容索引,则会引发错误。Passing "*" to db.collection.dropIndexes() drops all indexes except the _id index and the last remaining shard key compatible index, if one exists.
Starting in MongoDB 5.2, you can use 从MongoDB 5.2开始,即使在另一个索引上正在构建,您也可以使用db.collection.dropIndexes() to drop existing indexes on the same collection even if there is a build in progress on another index. db.collection.dropIndexes()删除同一集合上的现有索引。In earlier versions, attempting to drop a different index during an in-progress index build results in a 在早期版本中,在正在进行的索引构建过程中尝试删除其他索引会导致BackgroundOperationInProgressForNamespace error.BackgroundOperationInProgressForNamespace错误。
Kill related queries only仅终止相关查询
The dropIndexes() operation only kills queries that are using the index being dropped. This may include queries considering the index as part of query planning.dropIndexes()操作仅终止使用被丢弃索引的查询。这可能包括将索引视为查询规划的一部分的查询。
Resource Locking资源锁定
db.collection.dropIndexes() obtains an exclusive lock on the specified collection for the duration of the operation. 在操作期间获得指定集合的独占锁。All subsequent operations on the collection must wait until 对集合的所有后续操作都必须等到db.collection.dropIndexes() releases the lock.db.collection.dropIndexes()释放锁。
Index Names索引名称
If the method is passed an array of index names that includes a non-existent index, the method errors without dropping any of the specified indexes.如果向该方法传递了一个包含不存在索引的索引名称数组,则该方法会出错,但不会删除任何指定的索引。
_id Index索引
You cannot drop the default index on the 您不能删除_id field._id字段上的默认索引。
text Indexes全文索引
To drop a text index, specify the index name instead of the index specification document.要删除text索引,请指定索引名称,而不是索引规范文档。
Stop In-Progress Index Builds正在构建的停止索引
If an index specified to 如果指定给db.collection.dropIndexes() is still building, db.collection.dropIndexes() attempts to stop the in-progress build. db.collection.dropIndexes()的索引仍在构建中,db.collection.dropIndexes()将尝试停止正在进行的构建。Stopping an index build has the same effect as dropping the built index.停止索引构建与删除已构建的索引具有相同的效果。
For replica sets, run 对于副本集,在primary上运行db.collection.dropIndexes() on the primary. db.collection.dropIndexes()。The primary stops the index build and creates an associated "abortIndexBuild" oplog entry. 主程序停止索引构建并创建相关的"abortIndexBuild"oplog条目。Secondaries which replicate the "abortIndexBuild" oplog entry stop the in-progress index build and discard the build job. 复制“abortIndexBuild”oplog条目的辅助人员会停止正在进行的索引构建并丢弃构建作业。See Index Build Process for detailed documentation on the index build process.有关索引构建过程的详细文档,请参阅索引构建过程。
Use 使用currentOp to identify the index builds associated with a createIndexes or db.collection.createIndexes() operation. currentOp标识与createIndexes或db.collection.createIndexes()操作关联的索引构建。See Active Indexing Operations for an example.有关示例,请参阅活动索引操作。
Hidden Indexes隐藏索引
MongoDB offers the ability to hide or unhide indexes from the query planner. By hiding an index from the planner, you can evaluate the potential impact of dropping an index without actually dropping the index.MongoDB提供了在查询计划器中隐藏或取消隐藏索引的功能。通过对计划器隐藏索引,您可以在不实际删除索引的情况下评估删除索引的潜在影响。
If after the evaluation, the user decides to drop the index, you can drop the hidden index; i.e. you do not need to unhide it first to drop it.如果评估后,用户决定删除索引,则可以删除隐藏索引;也就是说,你不需要先解开它才能放下它。
If, however, the impact is negative, the user can unhide the index instead of having to recreate a dropped index. And because indexes are fully maintained while hidden, the indexes are immediately available for use once unhidden.但是,如果影响是负面的,用户可以取消隐藏索引,而不必重新创建已删除的索引。而且,由于索引在隐藏时是完全维护的,因此一旦取消隐藏,索引就可以立即使用。
For more information on hidden indexes, see Hidden Indexes.有关隐藏索引的详细信息,请参阅隐藏索引。