Re: [HACKERS] WAL logging problem in 9.4.3?

On Tue, Apr 2, 2019 at 6:54 AM Kyotaro HORIGUCHI
<horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> > By using DELETE and INSERT records to implement an UPDATE, you lose the ctid
> > chain and infomask bits that were present before crash recovery. If that's
> > okay in these circumstances, please write a comment explaining why.
>
> Sounds reasonable. Added a comment. (Honestly I completely forgot
> about that.. Thanks!) (0006)

If you haven't already, I think you should set up a master and a
standby and wal_consistency_checking=all and run tests of this feature
on the master and see if anything breaks on the master or the standby.
I'm not sure that emitting an insert or delete record is going to
reproduce the exact same state on the standby that exists on the
master.

+ * Insert log record. Using delete or insert log loses HOT chain
+ * information but that happens only when newbuf is different from
+ * buffer, where HOT cannot happen.

"HOT chain information" seems pretty vague.

--
Robert Haas
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