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Fix parallel-safety code for parallel aggregation.

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has_parallel_hazard() was ignoring the proparallel markings for
aggregates, which is no good.  Fix that.  There was no way to mark
an aggregate as actually being parallel-safe, either, so add a
PARALLEL option to CREATE AGGREGATE.

Patch by me, reviewed by David Rowley.
This commit is contained in:
Robert Haas
2016-04-05 16:06:15 -04:00
parent 09adc9a8c0
commit 41ea0c2376
8 changed files with 63 additions and 11 deletions
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9
doc/src/sgml/ref/create_aggregate.sgml
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@ -40,6 +40,7 @@ CREATE AGGREGATE <replaceable class="parameter">name</replaceable> ( [ <replacea
[ , MFINALFUNC_EXTRA ]
[ , MINITCOND = <replaceable class="PARAMETER">minitial_condition</replaceable> ]
[ , SORTOP = <replaceable class="PARAMETER">sort_operator</replaceable> ]
[ , PARALLEL = { SAFE | RESTRICTED | UNSAFE } ]
)
CREATE AGGREGATE <replaceable class="parameter">name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">arg_data_type</replaceable> [ , ... ] ]
@ -55,6 +56,8 @@ CREATE AGGREGATE <replaceable class="parameter">name</replaceable> ( [ [ <replac
[ , SERIALTYPE = <replaceable class="PARAMETER">serialtype</replaceable> ]
[ , INITCOND = <replaceable class="PARAMETER">initial_condition</replaceable> ]
[ , HYPOTHETICAL ]
[ , PARALLEL = { SAFE | RESTRICTED | UNSAFE } ]
)
<phrase>or the old syntax</phrase>
@ -684,6 +687,12 @@ SELECT col FROM tab ORDER BY col USING sortop LIMIT 1;
Currently, ordered-set aggregates do not need to support
moving-aggregate mode, since they cannot be used as window functions.
</para>
<para>
The meaning of <literal>PARALLEL SAFE</>, <literal>PARALLEL RESTRICTED</>,
and <literal>PARALLEL UNSAFE</> is the same as for
<xref linkend="sql-createfunction">.
</para>
</refsect1>
<refsect1>