diff options
| author | Robert Haas | 2016-04-26 12:31:38 +0000 |
|---|---|---|
| committer | Robert Haas | 2016-04-26 12:35:58 +0000 |
| commit | 77cd477c4ba885cfa1ba67beaa82e06f2e182b85 (patch) | |
| tree | 45cd79391da5ae88bdd4913756e9a98db2d6aa95 /doc/src | |
| parent | b7351ced425f3937f0a61adb4ade1d4b93bf751d (diff) | |
Enable parallel query by default.
Change max_parallel_degree default from 0 to 2. It is possible that
this is not a good idea, or that we should go with 1 worker rather
than 2, but we won't find out without trying it. Along the way,
reword the documentation for max_parallel_degree a little bit to
hopefully make it more clear.
Discussion: 20160420174631.3qjjhpwsvvx5bau5@alap3.anarazel.de
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/config.sgml | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 909b3e23c52..dce1daa73ae 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -2005,10 +2005,14 @@ include_dir 'conf.d' </term> <listitem> <para> - Sets the maximum degree of parallelism for an individual parallel - operation. Note that the requested number of workers may not actually - be available at runtime. Parallel workers are taken from the pool - of processes established by <xref linkend="guc-max-worker-processes">. + Sets the maximum number of workers that can be started for an + individual parallel operation. Parallel workers are taken from the + pool of processes established by + <xref linkend="guc-max-worker-processes">. Note that the requested + number of workers may not actually be available at runtime. If this + occurs, the plan will run with fewer workers than expected, which may + be inefficient. The default value is 2. Setting this value to 0 + disables parallel query. </para> </listitem> </varlistentry> |