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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2019-02-09 18:08:48 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2019-02-09 18:08:48 -0500 |
| commit | 1fb57af92069ee104c09e2016af9e0e620681be3 (patch) | |
| tree | 8bb9db8431972a220f6bd6f8b13e663049172583 /doc/src/sgml/ref/alter_function.sgml | |
| parent | 1a8d5afb0dfc5d0dcc6eda0656a34cb1f0cf0bdf (diff) | |
Create the infrastructure for planner support functions.
Rename/repurpose pg_proc.protransform as "prosupport". The idea is
still that it names an internal function that provides knowledge to
the planner about the behavior of the function it's attached to;
but redesign the API specification so that it's not limited to doing
just one thing, but can support an extensible set of requests.
The original purpose of simplifying a function call is handled by
the first request type to be invented, SupportRequestSimplify.
Adjust all the existing transform functions to handle this API,
and rename them fron "xxx_transform" to "xxx_support" to reflect
the potential generalization of what they do. (Since we never
previously provided any way for extensions to add transform functions,
this change doesn't create an API break for them.)
Also add DDL and pg_dump support for attaching a support function to a
user-defined function. Unfortunately, DDL access has to be restricted
to superusers, at least for now; but seeing that support functions
will pretty much have to be written in C, that limitation is just
theoretical. (This support is untested in this patch, but a follow-on
patch will add cases that exercise it.)
Discussion: https://postgr.es/m/15193.1548028093@sss.pgh.pa.us
Diffstat (limited to 'doc/src/sgml/ref/alter_function.sgml')
| -rw-r--r-- | doc/src/sgml/ref/alter_function.sgml | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/doc/src/sgml/ref/alter_function.sgml b/doc/src/sgml/ref/alter_function.sgml index d8747e07482..03ffa5945a2 100644 --- a/doc/src/sgml/ref/alter_function.sgml +++ b/doc/src/sgml/ref/alter_function.sgml @@ -40,6 +40,7 @@ ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="param PARALLEL { UNSAFE | RESTRICTED | SAFE } COST <replaceable class="parameter">execution_cost</replaceable> ROWS <replaceable class="parameter">result_rows</replaceable> + SUPPORT <replaceable class="parameter">support_function</replaceable> SET <replaceable class="parameter">configuration_parameter</replaceable> { TO | = } { <replaceable class="parameter">value</replaceable> | DEFAULT } SET <replaceable class="parameter">configuration_parameter</replaceable> FROM CURRENT RESET <replaceable class="parameter">configuration_parameter</replaceable> @@ -248,6 +249,24 @@ ALTER FUNCTION <replaceable>name</replaceable> [ ( [ [ <replaceable class="param </listitem> </varlistentry> + <varlistentry> + <term><literal>SUPPORT</literal> <replaceable class="parameter">support_function</replaceable></term> + + <listitem> + <para> + Set or change the planner support function to use for this function. + See <xref linkend="xfunc-optimization"/> for details. You must be + superuser to use this option. + </para> + + <para> + This option cannot be used to remove the support function altogether, + since it must name a new support function. Use <command>CREATE OR + REPLACE FUNCTION</command> if you need to do that. + </para> + </listitem> + </varlistentry> + <varlistentry> <term><replaceable>configuration_parameter</replaceable></term> <term><replaceable>value</replaceable></term> |