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Re: Performance issue in foreign-key-aware join estimation - Mailing list pgsql-hackers

From David Rowley
Subject Re: Performance issue in foreign-key-aware join estimation
Date
Msg-id CAKJS1f8hwUK=K3TWp-CuKCsLJa=3EUq-vx+RjngVDCnmWdjE9g@mail.gmail.com
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In response to Re: Performance issue in foreign-key-aware join estimation  (Andreas Seltenreich <seltenreich@gmx.de>)
Responses Re: Performance issue in foreign-key-aware join estimation
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On Mon, 22 Jul 2019 at 00:44, Andreas Seltenreich <seltenreich@gmx.de> wrote:
> sqlsmith triggers an assertion in this commit (3373c7155350):
>
> TRAP: FailedAssertion("!(rel->reloptkind == RELOPT_BASEREL)", File: "equivclass.c", Line: 764)

Thanks for the report.

It looks like this is caused by the join removal code removing the
LEFT JOIN and leaving a dead rel in the eclasses ec_relids.  The fix
is likely either to adjust the Assert to allow that or to add an if
test so that we only bother calling bms_add_member for base rels.  I'm
not quite sure yet.

-- 
 David Rowley                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

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