[HACKERS] failover vs. read only queries
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From: Fujii Masao on 9 Jun 2010 04:47 Hi, When the trigger file is created while the recovery keeps waiting for the release of the lock by read only queries, it might take a very long time for the standby to become the master. The recovery cannot go ahead until those read only queries have gone away. This would increase the downtime at the failover, and degrade the high availability. To fix the problem, when the trigger file is found, I think that we should cancel all the running read only queries immediately (or forcibly use -1 as the max_standby_delay since that point) and make the recovery go ahead. If some people prefer queries over failover even when they create the trigger file, we can make the trigger behavior selectable in response to the content of the trigger file like pg_standby does. This problem looks like a bug, so I'd like to fix that for 9.0. But the amount of code change might not be small. Thought? Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers |