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This page shows how to manage existing indexes. 本页显示如何管理现有索引。For instructions on creating indexes, refer to the specific index type pages.有关创建索引的说明,请参阅特定索引类型页面。
The following sections provide methods for viewing existing indexes on a collection or an entire database.以下各节提供了查看集合或整个数据库上现有索引的方法。
To view a list of all indexes on a collection in MongoDB Compass, click on the target collection in the left-hand pane and select the Indexes tab.要查看MongoDB Compass中集合上所有索引的列表,请单击左侧窗格中的目标集合,然后选择“索引”选项卡。
For details on the information displayed in this tab, refer to the Compass documentation.有关此选项卡中显示的信息的详细信息,请参阅Compass文档。
To return a list of all indexes on a collection, use the 要返回集合上所有索引的列表,请使用db.collection.getIndexes()
method or a similar method for your driver.db.collection.getIndexes()
方法或驱动程序的类似方法。
For example, to view all indexes on the 例如,要查看people
collection, run the following command:people
集合上的所有索引,请运行以下命令:
To list all the collection indexes in a database, you can use the following operation in the 要列出数据库中的所有集合索引,可以在mongo
shell:mongo
shell中使用以下操作:
Starting in version 3.0, MongoDB deprecates direct access to the 从3.0版开始,MongoDB不赞成直接访问system.indexes
collection, which had previously been used to list all indexes in a database.system.indexes
集合,该集合以前用于列出数据库中的所有索引。
To list all indexes of a certain type (e.g. hashed, text) for all collections in all database, you can use the following operation in the 要列出所有数据库中所有集合的特定类型(如哈希、text)的所有索引,可以在mongo
shell:mongo
shell中使用以下操作:
MongoDB provides two methods for removing indexes from a collection:MongoDB提供了两种从集合中删除索引的方法:
To remove an index, use the 要删除索引,请使用db.collection.dropIndex()
method.db.collection.dropIndex()
方法。
For example, the following operation removes an ascending index on the 例如,以下操作将删除tax-id
field in the accounts
collection:accounts
集合中tax-id
字段的升序索引:
The operation returns a document with the status of the operation:该操作返回一个带有操作状态的文档:
Where the value of 其中,nIndexesWas
reflects the number of indexes before removing this index.nIndexesWas
的值反映了删除此索引之前的索引数。
For text indexes, pass the index name to the 对于text索引,将索引名传递给db.collection.dropIndex()
method. db.collection.dropIndex()
方法。See Use the Index Name to Drop a text Index for details.有关详细信息,请参阅使用索引名删除文本索引。
Note
Starting in MongoDB 4.2, 从MongoDB 4.2开始,db.collection.dropIndexes()
can accept an array of index names.db.collection.dropIndexes()
可以接受一个索引名数组。
Starting in MongoDB 4.4, 从MongoDB 4.4开始,db.collection.dropIndexes()
can stop in-progress index builds. db.collection.dropIndexes()
可以停止正在进行的索引构建。See Aborts In-Progress Index Builds for more information.有关更多信息,请参阅中止进行中的索引生成。
You can also use the 还可以使用db.collection.dropIndexes()
to remove all indexes except for the _id index from a collection.db.collection.dropIndexes()
从集合中删除除_id
索引之外的所有索引。
For example, the following command removes all indexes from the 例如,以下命令将从accounts
collection:accounts
集合中删除所有索引:
These shell helpers provide wrappers around the 这些shell帮助程序围绕dropIndexes
database command. dropIndexes
数据库命令提供包装。Your client library may have a different or additional interface for these operations.对于这些操作,客户端库可能有不同的或附加的接口。
To remove an index from a collection in MongoDB Compass:要从MongoDB Compass中的集合中删除索引,请执行以下操作:
To modify an existing index, you need to drop and recreate the index. 要修改现有索引,需要删除并重新创建索引。The exception to this rule is TTL indexes, which can be modified via the 此规则的例外是TTL索引,可以通过collMod
command in conjunction with the index
collection flag.collMod
命令结合index
集合标志来修改。
To modify an existing index in MongoDB Compass, you need to drop and recreate the index.要修改MongoDB Compass中的现有索引,需要删除并重新创建索引。
A sharded collection has an inconsistent index if the collection does not have the exact same indexes (including the index options) on each shard that contains chunks for the collection. 如果一个分片集合在包含集合块的每个分片上没有完全相同的索引(包括索引选项),则该分片集合的索引不一致。Although inconsistent indexes should not occur during normal operations, inconsistent indexes can occur , such as:虽然正常操作期间不应出现不一致的索引,但也可能出现不一致的索引,例如:
unique
key constraint and one shard contains a chunk with duplicate documents. Starting in MongoDB 4.4 (and 4.2.6), the config server primary, by default, checks for index inconsistencies across the shards for sharded collections, and the command 从MongoDB 4.4(和4.2.6)开始,默认情况下,配置服务器主服务器会检查切分集合的切分之间的索引不一致,而命令serverStatus
, when run on the config server primary, returns the field shardedIndexConsistency
field to report on the number of sharded collections with index inconsistencies.serverStatus
在配置服务器主服务器上运行时,会返回字段shardedIndexConsistency
字段,以报告索引不一致的切分集合的数量。
If 如果shardedIndexConsistency
reports any index inconsistencies, you can run the following pipeline for your sharded collections until you find the inconsistencies.shardedIndexConsistency
报告任何索引不一致,您可以为您的分片集合运行以下管道,直到找到不一致。
Note
The following pipeline is for MongoDB 4.2.4 and above.以下管道适用于MongoDB 4.2.4及以上版本。
test.reviews
has inconsistent indexes across its associated shards:test.reviews
在其关联分片中是否有不一致的索引:
If the collection has inconsistent indexes, the aggregation for that collection returns details regarding the inconsistent indexes:如果集合具有不一致的索引,则该集合的聚合将返回有关不一致索引的详细信息:
The returned documents indicate two inconsistencies for the sharded collection 返回的文档表明切分集合test.reviews
:test.reviews
存在两个不一致之处:
page_1_score_1
is missing from the collection on shardB
.shardB
上的集合中缺少名为page_1_score_1
的索引。reviewDt_1
has inconsistent properties across the collection’s shards, specifically, the expireAfterSeconds
properties differ.reviewDt_1
的索引在集合的碎片中具有不一致的属性,具体来说,expireAfterSeconds
属性不同。You can either:你可以:
-OR--或者-
db.collection.createIndex()
from a mongos
instance. mongos
实例发出索引生成db.collection.createIndex()
。Drop the incorrect index from the collection on the affected shard(s) and rebuild the index. 从受影响碎片的集合中删除不正确的索引,然后重建索引。To rebuild the index, you can either:要重建索引,可以执行以下操作之一:
-OR--或者-
db.collection.createIndex()
from a mongos
instance. mongos
实例发出索引生成db.collection.createIndex()
。Alternatively, if the inconsistency is the 或者,如果不一致性是expireAfterSeconds
property, you can run the collMod
command to update the number of seconds instead of dropping and rebuilding the index.expireAfterSeconds
属性,则可以运行collMod
命令来更新秒数,而不是删除和重建索引。