| From: | jian he <jian(dot)universality(at)gmail(dot)com> |
|---|---|
| To: | Tommy Pavlicek <tommypav122(at)gmail(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Dagfinn Ilmari Mannsåker <ilmari(at)ilmari(dot)org>, pgsql-hackers(at)lists(dot)postgresql(dot)org, Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com> |
| Subject: | Re: [PATCH] Extend ALTER OPERATOR to support adding commutator, negator, hashes, and merges |
| Date: | 2023-09-25 14:55:01 |
| Message-ID: | CACJufxEieBFJrgPHUE-sM_aUZsLqt9ORGXpi2ogyksx9eata8Q@mail.gmail.com |
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| Lists: | pgsql-hackers |
in doc/src/sgml/ref/alter_operator.sgml
<varlistentry>
<term><literal>HASHES</literal></term>
<listitem>
<para>
Indicates this operator can support a hash join. Can only be set
when the operator does not support a hash join.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>MERGES</literal></term>
<listitem>
<para>
Indicates this operator can support a merge join. Can only be set
when the operator does not support a merge join.
</para>
</listitem>
</varlistentry>
------------------------
if the operator cannot support hash/merge join, it can't do ALTER
OPERATOR oprname(left_arg, right_arg) SET (HASHES/MERGES = false);
I think it means:
Can only be set when the operator does support a hash/merge join. Once
set to true, it cannot be reset to false.
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