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Add ALTER OPERATOR command, for changing selectivity estimator functions.

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Other options cannot be changed, as it's not totally clear if cached plans
would need to be invalidated if one of the other options change. Selectivity
estimator functions only change plan costs, not correctness of plans, so
those should be safe.

Original patch by Uriy Zhuravlev, heavily edited by me.
This commit is contained in:
Heikki Linnakangas
2015-07-14 18:17:55 +03:00
parent 705d397cd9
commit 321eed5f0f
13 changed files with 499 additions and 65 deletions
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34
doc/src/sgml/ref/alter_operator.sgml
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@@ -26,6 +26,11 @@ ALTER OPERATOR <replaceable>name</replaceable> ( { <replaceable>left_type</repla
ALTER OPERATOR <replaceable>name</replaceable> ( { <replaceable>left_type</replaceable> | NONE } , { <replaceable>right_type</replaceable> | NONE } )
SET SCHEMA <replaceable>new_schema</replaceable>
ALTER OPERATOR <replaceable>name</replaceable> ( { <replaceable>left_type</replaceable> | NONE } , { <replaceable>right_type</replaceable> | NONE } )
SET ( { RESTRICT = { <replaceable class="parameter">res_proc</replaceable> | NONE }
| JOIN = { <replaceable class="parameter">join_proc</replaceable> | NONE }
} [, ... ] )
</synopsis>
</refsynopsisdiv>
@@ -34,8 +39,7 @@ ALTER OPERATOR <replaceable>name</replaceable> ( { <replaceable>left_type</repla
<para>
<command>ALTER OPERATOR</command> changes the definition of
an operator. The only currently available functionality is to change the
owner of the operator.
an operator.
</para>
<para>
@@ -98,6 +102,25 @@ ALTER OPERATOR <replaceable>name</replaceable> ( { <replaceable>left_type</repla
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">res_proc</replaceable></term>
<listitem>
<para>
The restriction selectivity estimator function for this operator; write NONE to remove existing selectivity estimator.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">join_proc</replaceable></term>
<listitem>
<para>
The join selectivity estimator function for this operator; write NONE to remove existing selectivity estimator.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
@@ -109,6 +132,13 @@ ALTER OPERATOR <replaceable>name</replaceable> ( { <replaceable>left_type</repla
<programlisting>
ALTER OPERATOR @@ (text, text) OWNER TO joe;
</programlisting></para>
<para>
Change the restriction and join selectivity estimator functions of a custom operator <literal>a && b</literal> for type <type>int[]</type>:
<programlisting>
ALTER OPERATOR && (_int4, _int4) SET (RESTRICT = _int_contsel, JOIN = _int_contjoinsel);
</programlisting></para>
</refsect1>
<refsect1>