From: Jan Wieck <janwieck@yahoo.com>
Message-Id: <200112052126.fB5LQlp01967@saturn.jw.home>
Subject: Re: PL/pgSQL examples NOT involving functions
In-Reply-To: <20011127195917.10530.qmail@213-145-170-138.dd.nextgentel.com>
	from Aasmund Midttun Godal at "Nov 27, 2001 07:59:17 pm"
To: Aasmund Midttun Godal <postgresql@envisity.com>
Date: Wed, 5 Dec 2001 16:26:47 -0500 (EST)
CC: josh@agliodbs.com, pgsql-sql@postgresql.org
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Aasmund Midttun Godal wrote:
> Erm, sorry about the multiple postings, I just discovered a couple of interesting tidbits after I posted first...
>
> http://www.postgresql.org/idocs/index.php?plpgsql.html :
>
> "The PL/pgSQL call handler parses the function's source text and produces an internal binary instruction tree the first time the function is called."

    And  that  is  still  not  entirely  accurate.  At  the first
    function call  the  control  language  (IF,  WHEN,  etc.)  is
    parsed.  All  expressions  and queries are just remembered as
    strings with variables replaced by $n parameters.  Now  every
    statement will prepare a saved plan the first time it is hit.

    So when you have a  function  with  conditional  code  and  a
    specific  branch of that code is never called, the statements
    in there will never be prepared.


Jan

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