From: Tom Lane <tgl@sss.pgh.pa.us>
To: Yugo Nagata <nagata@sraoss.co.jp>
Cc: pgsql-hackers@postgresql.org
Subject: Re: CURRENT OF causes an error when IndexOnlyScan is used
Date: Wed, 31 Jan 2018 21:12:51 -0500
Message-ID: <22958.1517451171@sss.pgh.pa.us> (raw)
In-Reply-To: <20180201014444.f78358df.nagata@sraoss.co.jp>
References: <20180201013349.937dfc5f.nagata@sraoss.co.jp>
<20180201014444.f78358df.nagata@sraoss.co.jp>
Yugo Nagata <nagata@sraoss.co.jp> writes:
> I'm sorry the patch attached in the previous mail is broken and
> not raises a compile error. I attached the fixed patch.
This patch is almost certainly wrong: you can't assume that the scan-level
state matches the tuple we are currently processing at top level. Any
sort of delaying action, for instance a sort or materialize node in
between, would break it.
We need to either fix this aspect:
>> IndexOnlyScan returns a virtual tuple that doesn't have system
>> column, so we can not get ctid in the same way of other plans.
or else disallow using IndexOnlyScan when the ctid is needed.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, nagata@sraoss.co.jp
Subject: Re: CURRENT OF causes an error when IndexOnlyScan is used
In-Reply-To: <22958.1517451171@sss.pgh.pa.us>
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