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Re: Identity projection

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Amit kapila <amit.kapila@huawei.com>
Cc: "hlinnaka@iki.fi" <hlinnaka@iki.fi>, "'Kyotaro HORIGUCHI'" <horiguchi.kyotaro@lab.ntt.co.jp>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2013-02-09T03:33:13Z
Lists: pgsql-hackers 
Amit kapila <amit.kapila@huawei.com> writes:
>> if (!is_projection_capable_plan(result_plan) && compare_tlist_exprs(sub_tlist, result_plan->targetlist) )

> Sorry, the check I suggested in last mail should be as below:

> if (!is_projection_capable_plan(result_plan) && !compare_tlist_exprs(sub_tlist, result_plan->targetlist) )

You know, I was thinking that compare_tlist_exprs() was a pretty
unhelpfully-chosen name for a function returning boolean, and this
thinko pretty much proves the point.  It'd be better to call it
something like equivalent_tlists(), tlists_are_equivalent(), etc.
(I'm not caring for the emphasis on the exprs either, because I think
it'll also be necessary to compare resjunk fields for instance.)

			regards, tom lane