[Pgpool-general] pgpool detected difference of the number of inserted, updated, or deleted ...etc..

[Tatsuo Ishii]

Thanks. Actgually "the backends that differ from the master are
degenerated" is different from the current implementaion. To choose
the victim backend, we use "decide by majority". Suppose we have 3
nodes and they return:

Node 0: A
Node 1: B
Node 2: B

Then the victim is Node 0.

Suppose we have 4 nodes:

Node 0: A
Node 1: A
Node 2: B
Node 3: B

Unfortunately no one looses. In this case we chose Node 2 & 3 as
victims since Node 0 votes A.

Can you please modify your proposal?
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

> Here is my suggestion:
> 
> When set to true, if a SELECT statement returns a result set of records
> different between the backends, the backends that differ from the master
> are degenerated. This is only valid if the SELECT statement is part of a
> transaction and replicate_select is set to true. If set to false, the
> session is terminated and the backends are not degenerated. Default is
> false.
> 
> - -Ramon
> 
> 
> On 06/06/2010 10:25 PM, Tatsuo Ishii wrote:
> >> BTW : what is 'replication_stop_on_mismatch' and has it got anything to do
> >> with this issue ?
> > 
> > replication_stop_on_mismatch only affects SELECT. So it does not
> > anything to do with the issue.
> > 
> > I have to admit that current document regarding
> > replication_stop_on_mismatch is quite incorrect and hard to
> > understand:
> > 
> > "When set to true, pgpool-II degenerates the backends and keeps the
> > service only with the Master DB if data mismatch occurs. If false,
> > pgpool-II just terminates the query. Default is false."
> > 
> > Probably enhanced description for this would be something like
> > this. Please correct or raise questions. Grammatical corrections are
> > welcome as well.
> > 
> > "When set to true, if a backend returns different number of rows from
> > other backends return in SELECT (or SHOW), pgpool-II degenerates
> > it. This only take effects when the SELECT is running in an explicit
> > transaction and replicate_select is set to true.  If false, pgpool-II
> > just terminates the session. Default is false."
> > --
> > Tatsuo Ishii
> > SRA OSS, Inc. Japan
> > English: http://www.sraoss.co.jp/index_en.php
> > Japanese: http://www.sraoss.co.jp
> > _______________________________________________
> > Pgpool-general mailing list
> > Pgpool-general at pgfoundry.org
> > http://pgfoundry.org/mailman/listinfo/pgpool-general
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