[Pgcluster-general] pgreplicate misinterpretes success messages from all cluster dbs ?

[Holger Lehmann]

Hi Devrim, hi all,

thanks for the hint, that might just solved (that one) problem :-)
It was probably too late yesterday ...

@all:

I played around a bit. Here is what seems to happen:

If any one of the servers (silently) fail to execute an SQL statement,
like e.g. create tablespace, nothing bad happens up to now.
If you then try to run the query again, it fails on one server with the
message "already exists" while the other one might now be able to creta
the tablespace. The pgreplicta process does not seem to notice this an
tries to create the tablespace over and over again, without success.
I do not know how simple it would be to obtain the "real" error from the
postmaster, but maybe it would be wise, in some situations, not
to continuosly try to redo a query like:
"create database fubar"
if the server returns the error:
"database already exists"
The replicator the might need to check its logs and decide whether it
was "his" statement, so he should not try again on that machine or if he
never issued that command so he should stop trying and tell the caller
the failure immediately.
Thus, if it was "his" statement from earlier on, that did not succeed on
some servers, then he might just try those servers. On the other hand,
failing with an additional error message, like"
"these servers ... failed with message: ...., while these servers ...
succeeded", might help a lot for an admin to decide wether he made a
setup mistake or the replicator failed.

Any opinions ?

Regards,
Holger

Am Fr 26.10.2007 09:19 schrieb Devrim GÜNDÜZ <devrim at CommandPrompt.com>:

>Hi,
>
>On Fri, 2007-10-26 at 09:02 +0200, Holger Lehmann wrote:
>>2007-10-25 17:31:36 CEST LOG: could not write temporary statistics
>>file "global/pgstat.tmp": No space left on device
>>2007-10-25 17:31:51 CEST LOG: could not write temporary statistics
>>file "global/pgstat.tmp": No space left on device
>>2007-10-25 17:41:24 CEST ERROR: This query is not permitted when all
>>replication servers fell down
>
>So, you saw these errors, right?
>
>Regards,
>--
>Devrim GÜNDÜZ
>PostgreSQL Replication, Consulting, Custom Development, 24x7 support
>Managed Services, Shared and Dedicated Hosting
>Co-Authors: plPHP, ODBCng - http://www.commandprompt.com/
>
>

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