[Pgpool-general] lag threshold in slony

[Guillaume Lelarge]

Le 20/03/2011 10:44, Tatsuo Ishii a écrit :
>> I'm new to pgpool and to this list. I'm trying to set up a load
>> balancing cluster using pgpool-II 3.0 and slony. So far it seems to
>> work as expected, except for one key aspect: it seems as it is not
>> implemeted the lag check for slony, only for streaming replication.
>> I'm looking at pool_worker_child.c and it seems that the only mode
>> that does any check is streaming replication.
>> Are there any plans on implementing this feature?
>> There is another way to solve this (i.e. hooking an external command
>> to the health check)?
>>
>> Thanks in advance!
> 
> Currently there's no plan to implement the lag checking for Slony-I. I
> don't know it is possible for pgpool-II to extract lag info from
> Slony-I or not.

There is a specific view (sl_status) which allows you to check the lag
of one replication set. It shouldn't be too hard to do if you restrict
this config to one replication set (which is more or less what you need
to have if you're using the load balancing feature of pgpool with the
slony replication system).


-- 
Guillaume
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