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

[Ramon de Carvalho Valle]

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When set to true, if a SELECT statement returns a result set of records
different between the backends, the backends that differ from most
frequent result set 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 06/08/2010 09:49 PM, Tatsuo Ishii wrote:
> 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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