[pgpool-general: 5861] Re: Intermittent query failed when using pgpool2

[Tatsuo Ishii]

That's pretty normal because streaming replication is essentially
async process. A modification made on the primary node takes a while
before it is applied to the standbys. If Pgpool-II redirects the query
to standby, it is possible that it does not return the row you want to
retrieve.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp

> Hi Tatsuo,
> 
> Yes, it just returns no row. 
> 
> Best Rdgs,
> GB
> -----Original Message-----
> From: Tatsuo Ishii [mailto:ishii at sraoss.co.jp] 
> Sent: Tuesday, 16 January 2018 2:33 PM
> To: Goh Geok Bee <gbgoh at ntu.edu.sg>
> Cc: pgpool-general at pgpool.net
> Subject: Re: [pgpool-general: 5853] Intermittent query failed when using pgpool2
> 
> After checking pgpool.conf and pgpool log, it seems everything is ok to me.
> 
>>> We are using pgpool2 version 3.6.7. However, we encountered intermittent query failed on our application and we are using parameterized query.
> 
> What did you see exactly by "query failed"? Any errors from your application? Or just it returns no row?
> 
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese:http://www.sraoss.co.jp
> 
>> Hi Tatsuo,
>> 
>> Attached is the pgpool.conf. Looking forward to your reply. Thanks!
>> 
>> Best Rdgs,
>> GB
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> -----Original Message-----
>> From: Tatsuo Ishii [mailto:ishii at sraoss.co.jp]
>> Sent: Friday, 12 January 2018 6:19 AM
>> To: Goh Geok Bee <gbgoh at ntu.edu.sg>
>> Cc: pgpool-general at pgpool.net
>> Subject: Re: [pgpool-general: 5853] Intermittent query failed when 
>> using pgpool2
>> 
>>> We are using pgpool2 version 3.6.7. However, we encountered intermittent query failed on our application and we are using parameterized query.
>>>
>>> We noticed there is similar issue reported in https://github.com/brianc/node-postgres/issues/513 too.
>>>
>>> We are using master/slave mode for pgpool with 1 master and 1 slave postgresql 9.6 servers and only load balance mode is enabled on pgpool2. I have attached the pgpool log file. Pls check the log for 10:57:16 onwards. The query that did not returned result is "SELECT version FROM qtemplates WHERE qtemplate = 17958;" . However, if the same query is run again, it maybe successful.
>>>
>>> Anyone has encountered this before? Appreciate any advice. Thanks!
>> 
>> Can you share pgpool.conf? Hard to tell what's going on without configuration data.
>> 
>> Best regards,
>> --
>> Tatsuo Ishii
>> SRA OSS, Inc. Japan
>> English: http://www.sraoss.co.jp/index_en.php
>> Japanese:http://www.sraoss.co.jp
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