From: | Andres Freund <andres(at)2ndquadrant(dot)com> |
---|---|
To: | Noah Misch <noah(at)leadboat(dot)com> |
Cc: | Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Possible bug in CASE evaluation |
Date: | 2013-06-22 14:54:50 |
Message-ID: | 20130622145450.GC1254@alap2.anarazel.de |
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Lists: | pgsql-hackers |
On 2013-06-21 16:45:28 +0200, Andres Freund wrote:
> On 2013-06-21 09:51:05 -0400, Noah Misch wrote:
> > That being said, if we discover a simple-enough fix that performs well, we may
> > as well incorporate it.
>
> What about passing another parameter down eval_const_expressions_mutator
> (which is static, so changing the API isn't a problem) that basically
> tells us whether we actually should evaluate expressions or just perform
> the transformation?
> There's seems to be basically a couple of places where we call dangerous
> things:
> * simplify_function (via ->evaluate_function->evaluate_expr) which is
> called in a bunch of places
> * evaluate_expr which is directly called in T_ArrayExpr
> T_ArrayCoerceExpr
>
> All places I've inspected so far need to deal with simplify_function
> returning NULL anyway, so that seems like a viable fix.
*Prototype* patch - that seems simple enough - attached. Opinions?
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
Attachment | Content-Type | Size |
---|---|---|
0001-Don-t-evaluate-potentially-unreachable-parts-of-CASE.patch | text/x-patch | 5.8 KB |
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