Re: Expression Evaluator used for creating the plan tree / stmt ? - Mailing list pgsql-hackers

From Vaibhav Kaushal
Subject Re: Expression Evaluator used for creating the plan tree / stmt ?
Date
Msg-id BANLkTin_mXR3ECyPqUVosu7=D8cqO=oBQg@mail.gmail.com
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In response to Re: Expression Evaluator used for creating the plan tree / stmt ?  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Expression Evaluator used for creating the plan tree / stmt ?  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
<p>But somehow the execevalvar is being called. When i changed the logic of its working to use slot_getattr instead of
cute_datum_arrayfor the first run / call, everything just worked! <p>This would indicate surely that the function does
getcalled at least once before being called by executor for qual check. This is what got me confused - where does the
functionget called? Gdb trace says its first call comes through ExecutePlan but results say something else. Moreover,
gdbstill confuses me. Is there some gui to gdb? :( <p>The only thing i am trying to make sure that ExecEvalVar gets the
valuesfrom cute_datum_array only when called durin a scan, no way before it. May be there could be another way. I think
ihave to rethink about this.<br /> --<br /> Sent from my Android<div class="gmail_quote">On 25 May 2011 20:34, "Tom
Lane"<<a href="mailto:tgl@sss.pgh.pa.us">tgl@sss.pgh.pa.us</a>> wrote:<br type="attribution" />> Alvaro
Herrera<<a href="mailto:alvherre@commandprompt.com">alvherre@commandprompt.com</a>> writes:<br /> >>
Excerptsfrom Vaibhav Kaushal's message of mié may 25 05:52:32 -0400 2011:<br />>>> If the above is confusing,
Ijust want to ask: "Is expression evaluator,<br />>>> even in part responsible for {PLANNEDSTMT creation?"<br
/>> <br />>> Yeah, as far as I understood Tom's talk, the expr evaluator is used to<br />>> reduce some
expressionsto constants and such.<br />> <br />> The planner would never call it with an expression containing a
Var,<br/> > though.<br />> <br />> regards, tom lane<br /></div> 

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