From: Justin Pryzby <pryzby@telsasoft.com>
To: pgsql-hackers@lists.postgresql.org
Cc: Jeff Janes <jeff.janes@gmail.com>
Subject: Re: allow disabling indexscans without disabling bitmapscans
Date: Sat, 4 Jan 2020 13:34:16 -0600
Message-ID: <20200104193416.GX12066@telsasoft.com> (raw)
In-Reply-To: <20200104165047.GW12066@telsasoft.com>
References: <20200103141427.GK12066@telsasoft.com>
<CAMkU=1xcf-igvHSrta+gnTgE+K+Cnc-F=7z8G6YJTHwNSCyP1Q@mail.gmail.com>
<20200104165047.GW12066@telsasoft.com>
On Sat, Jan 04, 2020 at 10:50:47AM -0600, Justin Pryzby wrote:
> > Doesn't enable_indexscan=off accomplish this already? It is possible but
> > not terribly likely to switch from index to seq, rather than from index to
> > bitmap. (Unless the index scan was being used to obtain an ordered result,
> > but a hypothetical enable_bitmapscan=FORCE can't fix that).
>
> No, enable_indexscan=off implicitly disables bitmap index scans, since it does:
I don't know how I went wrong, but the regress tests clued me in..it's as Jeff
said.
Sorry for the noise.
Justin
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To: pgsql-performance@postgresql.org
Cc: pryzby@telsasoft.com, pgsql-hackers@lists.postgresql.org, jeff.janes@gmail.com
Subject: Re: allow disabling indexscans without disabling bitmapscans
In-Reply-To: <20200104193416.GX12066@telsasoft.com>
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