On Mon, Jul 23, 2018 at 12:13 PM, Andres Freund <andres@anarazel.de> wrote:
> My point is that we could just make HTSV treat them as recently dead, without incurring the issues of the bug you
referenced.
That doesn't seem sufficient. For example, it won't keep the
predecessor tuple's ctid field from being overwritten by a subsequent
updater -- and if that happens then the update chain is broken. Maybe
your idea of cross-checking at the end of each syscache lookup would
be sufficient to prevent that from happening, though. But I wonder if
there are subtler problems, too -- e.g. relfrozenxid vs. actual xmins
in the table, clog truncation, or whatever. There might be no
problem, but the idea that an aborted transaction is of no further
interest to anybody is pretty deeply ingrained in the system.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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