{"Entry":{"collection":"sql","key":"drop-index","name":"DROP INDEX","aliases":["dropindex"],"metadata":{"aliases":["dropindex"],"changed_in":["7.1","7.3","7.4","8.2","9.2"],"changes":[{"from":"6.4","purpose_changed":false,"renamed":null,"sections":{"added":[],"changed":["usage"],"removed":[]},"status":"changed","synopsis":null,"to":"6.5"},{"from":"6.5","purpose_changed":false,"renamed":null,"sections":{"added":[],"changed":["description"],"removed":[]},"status":"changed","synopsis":null,"to":"7.0"},{"from":"7.0","purpose_changed":true,"renamed":{"from_file":"sql-dropindex.htm","to_file":"sql-dropindex.html"},"sections":{"added":[],"changed":[],"removed":[]},"status":"changed","synopsis":{"added":["DROP INDEX index_name [, 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INDEX","object":"INDEX","position":1003,"present_in":["6.4","6.5","7.0","7.1","7.2","7.3","7.4","8.0","8.1","8.2","8.3","8.4","9.0","9.1","9.2","9.3","9.4","9.5","9.6","10","11","12","13","14","15","16","17","18","19","20"],"purpose":"remove an index","purpose_zh":"","related":["create-index"],"repair_provenance":{"original_source_revision":"wiki-repair-20261023:8addaf59ece6bbc7bfb1900ecb375b010120e3762de0e16ebf8db2dce6269063","receipt_sha256":"8f5fb9e7f3302960ff3ceeed734d9aa9406a00e9121c1f2f76ca08035215c6f2","repair":"wiki-repair-20261023"},"slug":"drop-index","source_rev":"wiki-repair-20261023:984c6f7656c3fdb1c0321439161601cf0e5838fb886bc904e49dfd49dc818ef1","synopsis":"DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]","verb":"DROP"}},"Definition":{"Collection":"sql","Key":"drop-index","SourceDatabase":"center","Version":"18","SourceTable":"sqlcmd","SourceKey":"drop-index","SourceRevision":"wiki-repair-20261023:984c6f7656c3fdb1c0321439161601cf0e5838fb886bc904e49dfd49dc818ef1","Facts":{"anchor":"SQL-DROPINDEX","description_zh":"移除一个索引","description_zh_html":"\u003cpre\u003eDROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]\u003c/pre\u003e\u003csection\u003e\u003ch2\u003e描述\u003c/h2\u003e\u003cp\u003e\n\u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e 从数据库系统中删除一个现有索引。要执行此命令，你必须是该索引的拥有者。\n  \u003c/p\u003e\u003c/section\u003e\u003csection\u003e\u003ch2\u003e参数\u003c/h2\u003e\u003cdiv class=\"variablelist\"\u003e\u003cdl class=\"variablelist\"\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eCONCURRENTLY\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n      删除索引时，不阻塞该索引所在表上的并发查询、插入、更新和删除。普通的 \u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e\n      会对该表获取 \u003ccode class=\"literal\"\u003eACCESS EXCLUSIVE\u003c/code\u003e 锁，阻塞其他访问，直到索引删除完成。使用该选项时，命令会改为等待相冲突的事务完成。\n     \u003c/p\u003e\u003cp\u003e\n      使用此选项时有若干限制需要注意。只能指定一个索引名，并且不支持\n      \u003ccode class=\"literal\"\u003eCASCADE\u003c/code\u003e 选项。（因此，支撑 \u003ccode class=\"literal\"\u003eUNIQUE\u003c/code\u003e\n      或 \u003ccode class=\"literal\"\u003ePRIMARY KEY\u003c/code\u003e 约束的索引不能以这种方式删除。）另外，普通的 \u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e 可以在事务块内执行，但 \u003ccode class=\"command\"\u003eDROP INDEX CONCURRENTLY\u003c/code\u003e 不可以。最后，分区表上的索引也不能使用该选项删除。\n     \u003c/p\u003e\u003cp\u003e\n      对于临时表，\u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e 始终是非并发的，因为没有其他会话可以访问它们，而且非并发删除索引的代价更低。\n     \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eIF EXISTS\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n        如果该索引不存在，则不要抛出错误。这种情况下会发出一条提示。\n     \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003cem class=\"replaceable\"\u003e\u003ccode\u003ename\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n      要移除的索引名称（可以被模式限定）。\n     \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eCASCADE\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n      自动删除依赖于该索引的对象，以及进一步依赖于这些对象的所有对象（参见\u003ca class=\"xref\" href=\"/zh/docs/18/ddl-depend.html\" title=\"5.15. 依赖跟踪\"\u003e第 5.15 节\u003c/a\u003e）。\n     \u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eRESTRICT\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003e\n      如果有任何对象依赖于该索引，则拒绝删除它。这是默认值。\n     \u003c/p\u003e\u003c/dd\u003e\u003c/dl\u003e\u003c/div\u003e\u003c/section\u003e\u003csection\u003e\u003ch2\u003e示例\u003c/h2\u003e\u003cp\u003e\n   此命令会删除索引 \u003ccode class=\"literal\"\u003etitle_idx\u003c/code\u003e：\n\n\u003c/p\u003e\u003cpre class=\"programlisting\"\u003e\nDROP INDEX title_idx;\n\u003c/pre\u003e\u003c/section\u003e\u003csection\u003e\u003ch2\u003e兼容性\u003c/h2\u003e\u003cp\u003e\n\u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e 是 \u003cspan class=\"productname\"\u003ePostgreSQL\u003c/span\u003e\n   的一种语言扩展。SQL 标准中没有关于索引的规定。\n  \u003c/p\u003e\u003c/section\u003e\u003csection\u003e\u003ch2\u003e另见\u003c/h2\u003e\u003cspan class=\"simplelist\"\u003e\u003ca class=\"xref\" href=\"/zh/docs/18/sql-createindex.html\" title=\"CREATE INDEX\"\u003e\u003cspan class=\"refentrytitle\"\u003eCREATE INDEX\u003c/span\u003e\u003c/a\u003e\u003c/span\u003e\u003c/section\u003e","file":"sql-dropindex.html","lang":"en","name":"DROP INDEX","purpose":"remove an index","purpose_zh":"移除一个索引","related":["create-index"],"sections":[{"html":"\u003cp\u003e\u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e drops an existing index from the database system. To execute this command you must be the owner of the index.\u003c/p\u003e","key":"description","title":"Description"},{"html":"\u003cdiv class=\"variablelist\"\u003e\u003cdl class=\"variablelist\"\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eCONCURRENTLY\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eDrop the index without locking out concurrent selects, inserts, updates, and deletes on the index's table. A normal \u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e acquires an \u003ccode class=\"literal\"\u003eACCESS EXCLUSIVE\u003c/code\u003e lock on the table, blocking other accesses until the index drop can be completed. With this option, the command instead waits until conflicting transactions have completed.\u003c/p\u003e\u003cp\u003eThere are several caveats to be aware of when using this option. Only one index name can be specified, and the \u003ccode class=\"literal\"\u003eCASCADE\u003c/code\u003e option is not supported. (Thus, an index that supports a \u003ccode class=\"literal\"\u003eUNIQUE\u003c/code\u003e or \u003ccode class=\"literal\"\u003ePRIMARY KEY\u003c/code\u003e constraint cannot be dropped this way.) Also, regular \u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e commands can be performed within a transaction block, but \u003ccode class=\"command\"\u003eDROP INDEX CONCURRENTLY\u003c/code\u003e cannot. Lastly, indexes on partitioned tables cannot be dropped using this option.\u003c/p\u003e\u003cp\u003eFor temporary tables, \u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e is always non-concurrent, as no other session can access them, and non-concurrent index drop is cheaper.\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eIF EXISTS\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eDo not throw an error if the index does not exist. A notice is issued in this case.\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003cem class=\"replaceable\"\u003e\u003ccode\u003ename\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eThe name (optionally schema-qualified) of an index to remove.\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eCASCADE\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eAutomatically drop objects that depend on the index, and in turn all objects that depend on those objects (see \u003ca href=\"/docs/18/ddl-depend.html\" title=\"5.15. Dependency Tracking\"\u003eSection 5.15\u003c/a\u003e).\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eRESTRICT\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eRefuse to drop the index if any objects depend on it. This is the default.\u003c/p\u003e\u003c/dd\u003e\u003c/dl\u003e\u003c/div\u003e","key":"parameters","title":"Parameters"},{"html":"\u003cp\u003eThis command will remove the index \u003ccode class=\"literal\"\u003etitle_idx\u003c/code\u003e:\u003c/p\u003e\u003cpre class=\"programlisting\"\u003eDROP INDEX title_idx;\n\u003c/pre\u003e","key":"examples","title":"Examples"},{"html":"\u003cp\u003e\u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e is a \u003cspan class=\"productname\"\u003ePostgreSQL\u003c/span\u003e language extension. There are no provisions for indexes in the SQL standard.\u003c/p\u003e","key":"compatibility","title":"Compatibility"},{"html":"\u003cspan class=\"simplelist\"\u003e\u003ca href=\"/wiki/sql/create-index/?v=18\" title=\"CREATE INDEX\"\u003e\u003cspan class=\"refentrytitle\"\u003eCREATE INDEX\u003c/span\u003e\u003c/a\u003e\u003c/span\u003e","key":"see_also","title":"See Also"}],"sections_same_as":"","slug":"18","synopsis_html":"DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] \u003cem class=\"replaceable\"\u003e\u003ccode\u003ename\u003c/code\u003e\u003c/em\u003e [, ...] [ CASCADE | RESTRICT ]","synopsis_text":"DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]","translation_provenance":{"inputs":[{"kind":"current-pgdoc-translation","path":"/Users/vonng/pgsty/pgdoc/zh/18/html/sql-dropindex.html","sha256":"d32f76aa2e18680280dbf92bdad4afbd55606b75f2f4e0d82ac20630e88dbfc5"}],"kind":"same-version-pgdoc","locale":"zh-Hans","source_revision":"b1b500221dbe5437cfca004d6b04d3f6e422765d","version":"18"},"zh_from":"same-version-pgdoc"},"ManualEvidence":{},"MeasuredEvidence":{}},"Text":{"Collection":"sql","Key":"drop-index","SourceDatabase":"center","Version":"18","Locale":"en","Title":"DROP INDEX","Summary":"remove an index","BodyHTML":"\u003cpre\u003eDROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]\u003c/pre\u003e\u003csection\u003e\u003ch2\u003eDescription\u003c/h2\u003e\u003cp\u003e\u003ccode\u003eDROP INDEX\u003c/code\u003e drops an existing index from the database system. To execute this command you must be the owner of the index.\u003c/p\u003e\u003c/section\u003e\u003csection\u003e\u003ch2\u003eParameters\u003c/h2\u003e\u003cdiv\u003e\u003cdl\u003e\u003cdt\u003e\u003cspan\u003e\u003ccode\u003eCONCURRENTLY\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eDrop the index without locking out concurrent selects, inserts, updates, and deletes on the index\u0026#39;s table. A normal \u003ccode\u003eDROP INDEX\u003c/code\u003e acquires an \u003ccode\u003eACCESS EXCLUSIVE\u003c/code\u003e lock on the table, blocking other accesses until the index drop can be completed. With this option, the command instead waits until conflicting transactions have completed.\u003c/p\u003e\u003cp\u003eThere are several caveats to be aware of when using this option. Only one index name can be specified, and the \u003ccode\u003eCASCADE\u003c/code\u003e option is not supported. (Thus, an index that supports a \u003ccode\u003eUNIQUE\u003c/code\u003e or \u003ccode\u003ePRIMARY KEY\u003c/code\u003e constraint cannot be dropped this way.) Also, regular \u003ccode\u003eDROP INDEX\u003c/code\u003e commands can be performed within a transaction block, but \u003ccode\u003eDROP INDEX CONCURRENTLY\u003c/code\u003e cannot. Lastly, indexes on partitioned tables cannot be dropped using this option.\u003c/p\u003e\u003cp\u003eFor temporary tables, \u003ccode\u003eDROP INDEX\u003c/code\u003e is always non-concurrent, as no other session can access them, and non-concurrent index drop is cheaper.\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan\u003e\u003ccode\u003eIF EXISTS\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eDo not throw an error if the index does not exist. A notice is issued in this case.\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan\u003e\u003cem\u003e\u003ccode\u003ename\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eThe name (optionally schema-qualified) of an index to remove.\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan\u003e\u003ccode\u003eCASCADE\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eAutomatically drop objects that depend on the index, and in turn all objects that depend on those objects (see \u003ca href=\"/docs/18/ddl-depend.html\" rel=\"nofollow\"\u003eSection 5.15\u003c/a\u003e).\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan\u003e\u003ccode\u003eRESTRICT\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eRefuse to drop the index if any objects depend on it. This is the default.\u003c/p\u003e\u003c/dd\u003e\u003c/dl\u003e\u003c/div\u003e\u003c/section\u003e\u003csection\u003e\u003ch2\u003eExamples\u003c/h2\u003e\u003cp\u003eThis command will remove the index \u003ccode\u003etitle_idx\u003c/code\u003e:\u003c/p\u003e\u003cpre\u003eDROP INDEX title_idx;\n\u003c/pre\u003e\u003c/section\u003e\u003csection\u003e\u003ch2\u003eCompatibility\u003c/h2\u003e\u003cp\u003e\u003ccode\u003eDROP INDEX\u003c/code\u003e is a \u003cspan\u003ePostgreSQL\u003c/span\u003e language extension. There are no provisions for indexes in the SQL standard.\u003c/p\u003e\u003c/section\u003e\u003csection\u003e\u003ch2\u003eSee Also\u003c/h2\u003e\u003cspan\u003e\u003ca href=\"/wiki/sql/create-index/?v=18\" title=\"CREATE INDEX\" rel=\"nofollow\"\u003e\u003cspan\u003eCREATE INDEX\u003c/span\u003e\u003c/a\u003e\u003c/span\u003e\u003c/section\u003e","SourceRevision":"wiki-repair-20261023:984c6f7656c3fdb1c0321439161601cf0e5838fb886bc904e49dfd49dc818ef1","ContentHash":"7be4e9515af641d7aaef146aa3816c31f30fb3c57b8c545819848bd276d9ad0f","Payload":{"related":["create-index"],"sections":[{"html":"\u003cp\u003e\u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e drops an existing index from the database system. To execute this command you must be the owner of the index.\u003c/p\u003e","key":"description","title":"Description"},{"html":"\u003cdiv class=\"variablelist\"\u003e\u003cdl class=\"variablelist\"\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eCONCURRENTLY\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eDrop the index without locking out concurrent selects, inserts, updates, and deletes on the index's table. A normal \u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e acquires an \u003ccode class=\"literal\"\u003eACCESS EXCLUSIVE\u003c/code\u003e lock on the table, blocking other accesses until the index drop can be completed. With this option, the command instead waits until conflicting transactions have completed.\u003c/p\u003e\u003cp\u003eThere are several caveats to be aware of when using this option. Only one index name can be specified, and the \u003ccode class=\"literal\"\u003eCASCADE\u003c/code\u003e option is not supported. (Thus, an index that supports a \u003ccode class=\"literal\"\u003eUNIQUE\u003c/code\u003e or \u003ccode class=\"literal\"\u003ePRIMARY KEY\u003c/code\u003e constraint cannot be dropped this way.) Also, regular \u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e commands can be performed within a transaction block, but \u003ccode class=\"command\"\u003eDROP INDEX CONCURRENTLY\u003c/code\u003e cannot. Lastly, indexes on partitioned tables cannot be dropped using this option.\u003c/p\u003e\u003cp\u003eFor temporary tables, \u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e is always non-concurrent, as no other session can access them, and non-concurrent index drop is cheaper.\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eIF EXISTS\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eDo not throw an error if the index does not exist. A notice is issued in this case.\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003cem class=\"replaceable\"\u003e\u003ccode\u003ename\u003c/code\u003e\u003c/em\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eThe name (optionally schema-qualified) of an index to remove.\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eCASCADE\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eAutomatically drop objects that depend on the index, and in turn all objects that depend on those objects (see \u003ca href=\"/docs/18/ddl-depend.html\" title=\"5.15. Dependency Tracking\"\u003eSection 5.15\u003c/a\u003e).\u003c/p\u003e\u003c/dd\u003e\u003cdt\u003e\u003cspan class=\"term\"\u003e\u003ccode class=\"literal\"\u003eRESTRICT\u003c/code\u003e\u003c/span\u003e\u003c/dt\u003e\u003cdd\u003e\u003cp\u003eRefuse to drop the index if any objects depend on it. This is the default.\u003c/p\u003e\u003c/dd\u003e\u003c/dl\u003e\u003c/div\u003e","key":"parameters","title":"Parameters"},{"html":"\u003cp\u003eThis command will remove the index \u003ccode class=\"literal\"\u003etitle_idx\u003c/code\u003e:\u003c/p\u003e\u003cpre class=\"programlisting\"\u003eDROP INDEX title_idx;\n\u003c/pre\u003e","key":"examples","title":"Examples"},{"html":"\u003cp\u003e\u003ccode class=\"command\"\u003eDROP INDEX\u003c/code\u003e is a \u003cspan class=\"productname\"\u003ePostgreSQL\u003c/span\u003e language extension. There are no provisions for indexes in the SQL standard.\u003c/p\u003e","key":"compatibility","title":"Compatibility"},{"html":"\u003cspan class=\"simplelist\"\u003e\u003ca href=\"/wiki/sql/create-index/?v=18\" title=\"CREATE INDEX\"\u003e\u003cspan class=\"refentrytitle\"\u003eCREATE INDEX\u003c/span\u003e\u003c/a\u003e\u003c/span\u003e","key":"see_also","title":"See Also"}],"sections_same_as":"","synopsis_html":"DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] \u003cem class=\"replaceable\"\u003e\u003ccode\u003ename\u003c/code\u003e\u003c/em\u003e [, ...] [ CASCADE | RESTRICT ]","synopsis_text":"DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]"}},"RequestedLocale":"en","Fallback":false,"Versions":["10","11","12","13","14","15","16","17","18","19","20","6.4","6.5","7.0","7.1","7.2","7.3","7.4","8.0","8.1","8.2","8.3","8.4","9.0","9.1","9.2","9.3","9.4","9.5","9.6"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}