From: Tom Lane <tgl@sss.pgh.pa.us>
To: Guillaume Smet <guillaume.smet@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Question about Bitmap Heap Scan/BitmapAnd
Date: Tue, 13 Feb 2007 11:49:13 -0500
Message-ID: <1285.1171385353@sss.pgh.pa.us> (raw)
In-Reply-To: <1d4e0c10702130832i35484abfmb229f5d0b4d9223b@mail.gmail.com>
References: <1d4e0c10702130832i35484abfmb229f5d0b4d9223b@mail.gmail.com>
"Guillaume Smet" <guillaume.smet@gmail.com> writes:
> What surprises me is that "parking" is in the filter and not in the
> Recheck Cond whereas it's part of the second Bitmap Index Scan of the
> Bitmap And node.
That's probably because of this:
/*
* When dealing with special or lossy operators, we will at this point
* have duplicate clauses in qpqual and bitmapqualorig. We may as well
* drop 'em from bitmapqualorig, since there's no point in making the
* tests twice.
*/
bitmapqualorig = list_difference_ptr(bitmapqualorig, qpqual);
What's not immediately clear is why the condition was in both lists to
start with. Perhaps idx_lieu_parking is a partial index with this as
its WHERE condition?
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, guillaume.smet@gmail.com
Subject: Re: Question about Bitmap Heap Scan/BitmapAnd
In-Reply-To: <1285.1171385353@sss.pgh.pa.us>
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