Re: [HACKERS] Optimizer cleanup to avoid redundant work on joins

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Optimizer cleanup to avoid redundant work on joins
Date: 2000-02-06 23:17:33
Message-ID: 200002062317.SAA13200@candle.pha.pa.us
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> Er ... um ... ahem ... DUH! The reason 6.5.3 works is that it does in
> fact keep join restrictinfo pointers in JoinPaths. I had eliminated
> those pointers (the thoroughly undocumented "pathinfo" field) because
> I thought that the lists were always the same as the parent relations'
> restrictinfo lists. Which they were --- at the time of creation of a
> JoinPath. What I missed was that prune.c moved a joinpath to belong
> to a different RelOptInfo with (potentially) a different restrictinfo
> list, but the joinpath needs to keep its original restrictinfo list.
>
> In other words, I broke it.
>
> Since surgery needs to be done anyway, I'm inclined to press ahead
> with the changes I was going to put off. On the other hand, if the
> patient had a vote, it might ask for a second opinion ;-)

Go for it. Beta is for testing. No better time to break things than
the present.

This is the first time I remember hearing about pre-beta release jitters
from many people.

--
Bruce Momjian | http://www.op.net/~candle
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026

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