diff options
Diffstat (limited to 'doc/src/sgml/ref/create_function.sgml')
| -rw-r--r-- | doc/src/sgml/ref/create_function.sgml | 38 |
1 files changed, 35 insertions, 3 deletions
diff --git a/doc/src/sgml/ref/create_function.sgml b/doc/src/sgml/ref/create_function.sgml index 3381c1db996..5309059de30 100644 --- a/doc/src/sgml/ref/create_function.sgml +++ b/doc/src/sgml/ref/create_function.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.70 2006/11/10 20:52:18 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.71 2007/01/22 01:35:19 tgl Exp $ --> <refentry id="SQL-CREATEFUNCTION"> @@ -26,6 +26,8 @@ CREATE [ OR REPLACE ] FUNCTION | IMMUTABLE | STABLE | VOLATILE | CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT | [ EXTERNAL ] SECURITY INVOKER | [ EXTERNAL ] SECURITY DEFINER + | COST <replaceable class="parameter">execution_cost</replaceable> + | ROWS <replaceable class="parameter">result_rows</replaceable> | AS '<replaceable class="parameter">definition</replaceable>' | AS '<replaceable class="parameter">obj_file</replaceable>', '<replaceable class="parameter">link_symbol</replaceable>' } ... @@ -52,7 +54,7 @@ CREATE [ OR REPLACE ] FUNCTION </para> <para> - To update the definition of an existing function, use + To replace the current definition of an existing function, use <command>CREATE OR REPLACE FUNCTION</command>. It is not possible to change the name or argument types of a function this way (if you tried, you would actually be creating a new, distinct function). @@ -290,6 +292,35 @@ CREATE [ OR REPLACE ] FUNCTION </varlistentry> <varlistentry> + <term><replaceable class="parameter">execution_cost</replaceable></term> + + <listitem> + <para> + A positive number giving the estimated execution cost for the function, + in units of <xref linkend="guc-cpu-operator-cost">. If the function + returns a set, this is the cost per returned row. If the cost is + not specified, 1 unit is assumed for C-language and internal functions, + and 100 units for functions in all other languages. Larger values + cause the planner to try to avoid evaluating the function more often + than necessary. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable class="parameter">result_rows</replaceable></term> + + <listitem> + <para> + A positive number giving the estimated number of rows that the planner + should expect the function to return. This is only allowed when the + function is declared to return a set. The default assumption is + 1000 rows. + </para> + </listitem> + </varlistentry> + + <varlistentry> <term><replaceable class="parameter">definition</replaceable></term> <listitem> @@ -400,7 +431,8 @@ CREATE FUNCTION foo(int, out text) ... <para> When repeated <command>CREATE FUNCTION</command> calls refer to - the same object file, the file is only loaded once. To unload and + the same object file, the file is only loaded once per session. + To unload and reload the file (perhaps during development), use the <xref linkend="sql-load" endterm="sql-load-title"> command. </para> |