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authorMichael Paquier <michael@paquier.xyz>2020-01-22 09:49:18 +0900
committerMichael Paquier <michael@paquier.xyz>2020-01-22 09:49:18 +0900
commita904abe2e284f570168839e52e18ef0b7f26179d (patch)
tree73d75ddca5398a2307754a6f0c4fa92f3c54f8c0 /doc/src
parent9b9c5f279e8261ab90dc64559911d2578288b7e9 (diff)
downloadpostgresql-a904abe2e284f570168839e52e18ef0b7f26179d.tar.gz
postgresql-a904abe2e284f570168839e52e18ef0b7f26179d.zip
Fix concurrent indexing operations with temporary tables
Attempting to use CREATE INDEX, DROP INDEX or REINDEX with CONCURRENTLY on a temporary relation with ON COMMIT actions triggered unexpected errors because those operations use multiple transactions internally to complete their work. Here is for example one confusing error when using ON COMMIT DELETE ROWS: ERROR: index "foo" already contains data Issues related to temporary relations and concurrent indexing are fixed in this commit by enforcing the non-concurrent path to be taken for temporary relations even if using CONCURRENTLY, transparently to the user. Using a non-concurrent path does not matter in practice as locks cannot be taken on a temporary relation by a session different than the one owning the relation, and the non-concurrent operation is more effective. The problem exists with REINDEX since v12 with the introduction of CONCURRENTLY, and with CREATE/DROP INDEX since CONCURRENTLY exists for those commands. In all supported versions, this caused only confusing error messages to be generated. Note that with REINDEX, it was also possible to issue a REINDEX CONCURRENTLY for a temporary relation owned by a different session, leading to a server crash. The idea to enforce transparently the non-concurrent code path for temporary relations comes originally from Andres Freund. Reported-by: Manuel Rigger Author: Michael Paquier, Heikki Linnakangas Reviewed-by: Andres Freund, Álvaro Herrera, Heikki Linnakangas Discussion: https://postgr.es/m/CA+u7OA6gP7YAeCguyseusYcc=uR8+ypjCcgDDCTzjQ+k6S9ksQ@mail.gmail.com Backpatch-through: 9.4
Diffstat (limited to 'doc/src')
-rw-r--r--doc/src/sgml/ref/create_index.sgml5
-rw-r--r--doc/src/sgml/ref/drop_index.sgml5
-rw-r--r--doc/src/sgml/ref/reindex.sgml5
3 files changed, 15 insertions, 0 deletions
diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index 629a31ef795..ab362a0dc52 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -129,6 +129,11 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ [ IF NOT EXISTS ] <replaceable class=
&mdash; see <xref linkend="sql-createindex-concurrently"
endterm="sql-createindex-concurrently-title"/>.
</para>
+ <para>
+ For temporary tables, <command>CREATE INDEX</command> is always
+ non-concurrent, as no other session can access them, and
+ non-concurrent index creation is cheaper.
+ </para>
</listitem>
</varlistentry>
diff --git a/doc/src/sgml/ref/drop_index.sgml b/doc/src/sgml/ref/drop_index.sgml
index 2a8ca5bf689..0aedd71bd68 100644
--- a/doc/src/sgml/ref/drop_index.sgml
+++ b/doc/src/sgml/ref/drop_index.sgml
@@ -58,6 +58,11 @@ DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] <replaceable class="parameter">name</r
performed within a transaction block, but
<command>DROP INDEX CONCURRENTLY</command> cannot.
</para>
+ <para>
+ For temporary tables, <command>DROP INDEX</command> is always
+ non-concurrent, as no other session can access them, and
+ non-concurrent index drop is cheaper.
+ </para>
</listitem>
</varlistentry>
diff --git a/doc/src/sgml/ref/reindex.sgml b/doc/src/sgml/ref/reindex.sgml
index 5aa59d3b751..c54a7c420d4 100644
--- a/doc/src/sgml/ref/reindex.sgml
+++ b/doc/src/sgml/ref/reindex.sgml
@@ -166,6 +166,11 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { IN
&mdash; see <xref linkend="sql-reindex-concurrently"
endterm="sql-reindex-concurrently-title"/>.
</para>
+ <para>
+ For temporary tables, <command>REINDEX</command> is always
+ non-concurrent, as no other session can access them, and
+ non-concurrent reindex is cheaper.
+ </para>
</listitem>
</varlistentry>