Re: Re: Hot Standby query cancellation and Streaming Replication integration
Dimitri Fontaine <dfontaine@hi-media.com>
From: Dimitri Fontaine <dfontaine@hi-media.com>
To: Josh Berkus <josh@agliodbs.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2010-02-28T20:54:52Z
Lists: pgsql-hackers
Josh Berkus <josh@agliodbs.com> writes: > 2) A more usable vacuum_defer_cleanup_age. If it was feasible for a > user to configure the master to not vacuum records less than, say, 5 > minutes dead, then that would again offer the choice to the user of > slightly degraded performance on the master (acceptable) vs. lots of > query cancel (unacceptable). I'm going to test Greg's case with > vacuum_cleanup_age used fairly liberally to see if this approach has > merit. I think that to associate any time based interval notion with the XID flow, you need a ticker. We already took the txid and txid_snapshot types and functions from Skytools, which took them from Slony. Maybe we could consider borrowing pgqd, the C version of the ticker, for being able to specify in human time how long a dead transaction is allowed to remain in the heap? http://github.com/markokr/skytools-dev/tree/master/sql/ticker/ Regards, -- dim