[pgpool-general: 6025] Re: Streaming Replication Check

[Jaime Soler]

Hi

2018-04-05 12:28 GMT+02:00 Mathias Buresch <mathias.buresch at de.clara.net>:

> Hi there,
>
>
>
> maybe someone can help me to understand how “Streaming Replication Check”
> is working.
>
>
>
> Is it checking replication lag by using pg_last_xlog_receive_location()
> and pg_last_xlog_replay_location() ??
>

check_replication_time_lag function call those functions
https://github.com/mbell8903/pgpool-II/blob/master/src/streaming_replication/pool_worker_child.c#L230
https://github.com/mbell8903/pgpool-II/blob/master/src/streaming_replication/pool_worker_child.c#L289-L295


> Am I right that those check should not be dependent from database I use?
>
> If it is like that why I need “sr_check_database”?
>

this is the convention of postgresql connection requiered but it will use
postgres as default.

>
>
> Also why “delay_threshold” cannot be 0? Why 0 is disabling it?
>
>
>
> The reason I ask is that a customer has problem with inserting something
> and “directly” read the insert and don’t get the correct answer – maybe
> because it is not synced and loadbalancing is forwarding to slave?!
>
>
>
In my opinion your standby node was async when your customer tried to read
previous inserted data on master node. Did you try to set delay_threshold ?



> Mit herzlichen Grüßen
>
> Mathias Buresch
> Systems Engineer
> --
> mathias.buresch at de.clara.net
> Tel: +49 (69) 40 80 18 - 265
> Fax: +49 (69) 40 80 18 - 129
>
> Claranet GmbH
> Hanauer Landstraße 196
> 60314 Frankfurt
>
> Geschäftsführung Olaf Fischer
> Hrb 50381 AG Frankfurt am Main
> Vat-ID de 812918694
>
> http://www.claranet.de
>
>
>
> _______________________________________________
> pgpool-general mailing list
> pgpool-general at pgpool.net
> http://www.pgpool.net/mailman/listinfo/pgpool-general
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.sraoss.jp/pipermail/pgpool-general/attachments/20180405/d0c1656f/attachment.html>