[Please CC any replies] Hi,
Here is a patch to the documentation clarifying some minor issues. The first is to the main SPI documentation clarifying that SPI isn't available unless there is a current snapshot (leading to the "no snapshot has been set" error). The second clarifies when the get_fn_expr_rettype() and get_fn_expr_argtype() functions can actually provide the information requested. Have a nice day, -- Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/ > Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a > tool for doing 5% of the work and then sitting around waiting for someone > else to do the other 95% so you can sue them.
Index: doc/src/sgml/spi.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql/doc/src/sgml/spi.sgml,v
retrieving revision 1.42
diff -u -r1.42 spi.sgml
--- doc/src/sgml/spi.sgml 29 Jul 2005 13:00:03 -0000 1.42
+++ doc/src/sgml/spi.sgml 13 Aug 2005 19:10:54 -0000
@@ -29,6 +29,14 @@
</para>
</note>
+ <note>
+ <para>
+ SPI can not be used in functions called prior to the start of query
+ execution because there is no current snapshot at that point. Examples of
+ this include type input functions and cost estimation functions.
+ </para>
+ </note>
+
<para>
To avoid misunderstanding we'll use the term <quote>function</quote>
when we speak of <acronym>SPI</acronym> interface functions and
Index: doc/src/sgml/xfunc.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql/doc/src/sgml/xfunc.sgml,v
retrieving revision 1.103
diff -u -r1.103 xfunc.sgml
--- doc/src/sgml/xfunc.sgml 30 May 2005 23:09:07 -0000 1.103
+++ doc/src/sgml/xfunc.sgml 13 Aug 2005 19:10:55 -0000
@@ -2778,6 +2778,16 @@
as an alternative to <function>get_fn_expr_rettype</>.
</para>
+ <footnote>
+ <para>
+ Information about argument and return types is generally available if
+ you are executing a normal function within a normal query. However, it
+ can be missing for implicitly used functions, such as type
+ input/output functions that are called directly by the planner before
+ the query starts.
+ </para>
+ </footnote>
+
<para>
For example, suppose we want to write a function to accept a single
element of any type, and return a one-dimensional array of that type:
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