From: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
---|---|
To: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Cc: | Chris Redekop <chris(at)replicon(dot)com> |
Subject: | Hot Standby startup with overflowed snapshots |
Date: | 2011-10-27 13:26:00 |
Message-ID: | CA+U5nMJ3-kAFtRZo5g7gRjp0iA4BwdavbbH9_UQsekeqT-2m1A@mail.gmail.com |
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Chris Redekop's recent report of slow startup for Hot Standby has made
me revisit the code there.
Although there isn't a bug, there is a missed opportunity for starting
up faster which could be the source of Chris' annoyance.
The following patch allows a faster startup in some circumstances.
The patch also alters the log levels for messages and gives a single
simple message for this situation. The log will now say
LOG: recovery snapshot waiting for non-overflowed snapshot or until
oldest active xid on standby is at least %u (now %u)
...multiple times until snapshot non-overflowed or xid reached...
whereas before the first LOG message shown was
LOG: consistent state delayed because recovery snapshot incomplete
and only later, at DEBUG2 do you see
LOG: recovery snapshot waiting for %u oldest active xid on standby is %u
...multiple times until xid reached...
Comments please.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
Attachment | Content-Type | Size |
---|---|---|
faster_hot_standby_startup_withsubxacts.v1.patch | application/octet-stream | 3.3 KB |
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