Horton

Re: [HACKERS] WAL logging problem in 9.4.3?

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
Cc: Noah Misch <noah@leadboat.com>, Dmitry Dolgov <9erthalion6@gmail.com>, Andrew Dunstan <andrew.dunstan@2ndquadrant.com>, hlinnaka <hlinnaka@iki.fi>, Michael Paquier <michael@paquier.xyz>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2019-04-03T14:16:02Z
Lists: pgsql-hackers 
On Tue, Apr 2, 2019 at 6:54 AM Kyotaro HORIGUCHI
<horiguchi.kyotaro@lab.ntt.co.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
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Add perl2host call missing from a new test file.

  2. Skip WAL for new relfilenodes, under wal_level=minimal.

  3. Revert "Skip WAL for new relfilenodes, under wal_level=minimal."

  4. Back-patch log_newpage_range().

  5. During heap rebuild, lock any TOAST index until end of transaction.

  6. In log_newpage_range(), heed forkNum and page_std arguments.

  7. Back-patch src/test/recovery and PostgresNode from 9.6 to 9.5.

  8. Reduce pg_ctl's reaction time when waiting for postmaster start/stop.

  9. Accelerate end-of-transaction dropping of relations

  10. Redesign the planner's handling of index-descent cost estimation.

  11. Make TRUNCATE do truncate-in-place when processing a relation that was created