diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2016-06-16 13:47:20 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2016-06-16 13:47:20 -0400 |
| commit | 75be66464cb1bffa1e5757907b9a04ad5afc7859 (patch) | |
| tree | 71d51f8b6e3ba127480cf6165b4b2c165c2fea0f /doc/src | |
| parent | 3b5a2a8856b810ed354fb6dbb7df8d7325ece82f (diff) | |
Invent min_parallel_relation_size GUC to replace a hard-wired constant.
The main point of doing this is to allow the cutoff to be set very small,
even zero, to allow parallel-query behavior to be tested on relatively
small tables such as we typically use in the regression tests. But it
might be of use to users too. The number-of-workers scaling behavior in
create_plain_partial_paths() is pretty ad-hoc and subject to change, so
we won't expose anything about that, but the notion of not considering
parallel query at all for tables below size X seems reasonably stable.
Amit Kapila, per a suggestion from me
Discussion: <17170.1465830165@sss.pgh.pa.us>
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/config.sgml | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index e0e5a1edc60..a82bf065a06 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -3699,6 +3699,20 @@ include_dir 'conf.d' </listitem> </varlistentry> + <varlistentry id="guc-min-parallel-relation-size" xreflabel="min_parallel_relation_size"> + <term><varname>min_parallel_relation_size</varname> (<type>integer</type>) + <indexterm> + <primary><varname>min_parallel_relation_size</> configuration parameter</primary> + </indexterm> + </term> + <listitem> + <para> + Sets the minimum size of relations to be considered for parallel scan. + The default is 8 megabytes (<literal>8MB</>). + </para> + </listitem> + </varlistentry> + <varlistentry id="guc-effective-cache-size" xreflabel="effective_cache_size"> <term><varname>effective_cache_size</varname> (<type>integer</type>) <indexterm> |