On Tue, Jun 17, 2014 at 12:30 AM, Abhijit Menon-Sen a...@2ndquadrant.com
wrote:
(Cc: to pgsql-bugs dropped.)
At 2014-03-17 18:24:55 +1100, kommi.harib...@gmail.com wrote:
*** a/doc/src/sgml/xfunc.sgml
--- b/doc/src/sgml/xfunc.sgml
***
*** 153,159 SELECT clean_emp();
--- 153,186
(literal\/) (assuming escape string syntax) in the body of
the function (see xref linkend=sql-syntax-strings).
/para
+
+sect2 id=xfunc-sql-function-parsing-mechanism
+ titleParsing mechanism of a function/title
+indexterm
+ primaryfunction/primary
+ secondaryparsing mechanism/secondary
+/indexterm
I suggest Catalog changes within functions instead of the above title.
+ para
+ The body of an SQL function is parsed as if it were a single -
multi-part
+ statement and thus uses a constant snapshot of the system catalogs for
+ every sub-statement therein. Commands that alter the catalog will
likely not
+ work as expected.
+ /para
+
+ para
+ For example: Issuing CREATE TEMP TABLE within an SQL function will
add
+ the table to the catalog but subsequent statements in the same
function will
+ not see those additions and thus the temporary table will be
invisible to them.
+ /para
+
+ para
+ Thus it is generally advised that applicationPL/pgSQL/ be used,
instead of
+ acronymSQL/acronym, when any catalog visibilities are required in
the same function.
+ /para
+/sect2
I don't think that much text is warranted. I suggest something like the
following condensed wording:
para
The body of an SQL function is parsed as if it were a single
multi-part statement, using a constant snapshot of the system
catalogs. The effect of any commands that alter the catalogs
(e.g. CREATE TEMP TABLE) will therefore not be visible to
subsequent commands in the function body.
/para
para
The recommended workaround is to use applicationPL/PgSQL/.
/para
Does that seem sensible to you?
Looks good, Thanks for the review.
Updated patch attached.
Regards,
Hari Babu
Fujitsu Australia
sql_functions_parsing_doc_v2.patch
Description: Binary data
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