Simon Riggs wrote:
On Mon, 2009-04-20 at 17:47 +0300, Heikki Linnakangas wrote:
At the end of archive recovery, the server always probes for the
timeline by requesting history files until it fails to find one. That
probing should remove the trigger file if it hasn't been removed by
then. It's a bit coincidental to rely on that, but at least it's simple.
The assumption we're making is that the server won't exit recovery
before asking restore_command for a file that doesn't exist.
If you really want to simplify this, then we should have a final_command
parameter for a command to be executed at the end of recovery. That
would make the change to pg_standby very simple and allow for a very
simple final_command also. That would make the logic similar to what we
do for aggregates: transition function and final function.
We could call it restore_cleanup_command or something similar.
Hmm, that might indeed be a cleaner interface. However, that throws the
idea of backpatching out of the window, and will make it impossible to
run a PG 8.4 pg_standby against a PG 8.3 server. Do we want to add the
new parameter for 8.4 anyway?
I suspect this option will make you consider Fujii-san's patch in a
better light. :-)
No, removing trigger file as soon as a non-existant file is requested
still seems simpler than deleting it whenever a timeline history file is
requested.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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