diff options
| -rw-r--r-- | doc/src/sgml/ref/reindex.sgml | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml index e6b25ee670f..6a0eca8b9ac 100644 --- a/doc/src/sgml/ref/reindex.sgml +++ b/doc/src/sgml/ref/reindex.sgml @@ -275,7 +275,12 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { IN considerations are rather different. <command>REINDEX</command> locks out writes but not reads of the index's parent table. It also takes an <literal>ACCESS EXCLUSIVE</literal> lock on the specific index being processed, - which will block reads that attempt to use that index. In contrast, + which will block reads that attempt to use that index. In particular, + the query planner tries to take an <literal>ACCESS SHARE</literal> + lock on every index of the table, regardless of the query, and so + <command>REINDEX</command> blocks virtually any queries except for some + prepared queries whose plan has been cached and which don't use this very + index. In contrast, <command>DROP INDEX</command> momentarily takes an <literal>ACCESS EXCLUSIVE</literal> lock on the parent table, blocking both writes and reads. The subsequent <command>CREATE INDEX</command> locks out |