Horton

Re: XMin Hot Standby Feedback patch

Fujii Masao <masao.fujii@gmail.com>

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From: Fujii Masao <masao.fujii@gmail.com>
To: Simon Riggs <simon@2ndquadrant.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>, Daniel Farina <daniel@heroku.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2011-02-16T02:25:30Z
Lists: pgsql-hackers 
On Wed, Feb 16, 2011 at 6:15 AM, Simon Riggs <simon@2ndquadrant.com> wrote:
> On Tue, 2011-02-15 at 12:15 -0500, Robert Haas wrote:
>> Looks pretty good to me, though I haven't tested it.  I like some of
>> the safety valves you put in there, but I don't understand this part
>
> Reworked logic covering all feedback, plus tests, plus docs.
>
> Last comments before commit please.

When I started the standby with hot_standby = off and hot_standby_feedback = on,
I got the following assertion error.

-----------------
sby LOG:  streaming replication successfully connected to primary
TRAP: FailedAssertion("!(((result) >= ((TransactionId) 3)))", File:
"procarray.c", Line: 1027)
act LOG:  unexpected EOF on standby connection
sby LOG:  WAL receiver process (PID 17572) was terminated by signal 6: Aborted
sby LOG:  terminating any other active server processes
-----------------

vacuum_defer_cleanup_age on the *standby* should not affect the
feedback xid.

VACUUM TABLE on the *primary* doesn't use the feedback xid at all.
Is this intentional?

Regards,

-- 
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center