Movatterモバイル変換


[0]ホーム

URL:


Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

Sign up
Appearance settings

Commit6e2e12c

Browse files
committed
Remove overly-pessimistic statement about constraint exclusion.
As of 9.2, constraint exclusion should work okay with prepared statements:the planner will try custom plans with actual values of the parameters,and observe that they are a lot cheaper than the generic plan, and thusnever fall back to using the generic plan. Noted by Tatsuhito Kasahara.
1 parentb33f611 commit6e2e12c

File tree

1 file changed

+5
-5
lines changed

1 file changed

+5
-5
lines changed

‎doc/src/sgml/ddl.sgml

Lines changed: 5 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -2975,11 +2975,11 @@ ANALYZE measurement;
29752975
<listitem>
29762976
<para>
29772977
Constraint exclusion only works when the query's <literal>WHERE</>
2978-
clause contains constants. A parameterized query will not be
2979-
optimized, since the planner cannot know which partitions the
2980-
parameter value might select at run time. Forthe same reason,
2981-
<quote>stable</> functions such as <function>CURRENT_DATE</function>
2982-
must be avoided.
2978+
clause contains constants (or externally supplied parameters).
2979+
For example, a comparison against a non-immutable function such as
2980+
<function>CURRENT_TIMESTAMP</function> cannot be optimized, sincethe
2981+
planner cannot know which partition thefunction value might fall
2982+
into at run time.
29832983
</para>
29842984
</listitem>
29852985

0 commit comments

Comments
 (0)

[8]ページ先頭

©2009-2025 Movatter.jp