[pgpool-general: 3352] Re: Master/Slave (stream) mode - Memory depletion

[Christian Affolter]

Hi Muhammad,

I'm glad to report that the problem seems to be solved, the daemons are
running for over 17 hours and the memory usage remains stable.

Regards
Christian

On 04.12.2014 17:04, Christian Affolter wrote:
> Hi
> 
> thank you very much!
> 
> I've installed the current V3_4_STABLE Git branch on both nodes and
> restarted the pgpool-II daemons. I will check the memory usage by
> tomorrow and provide feedback.
> 
> By the way, if any Gentoo users are on this list, I've created some new
> (live) dev-db/pgpool2 ebuilds, which can be found on GitHub [1].
> 
> Thanks again and best regards
> Christian
> 
> 
> [1]
> https://github.com/stepping-stone/sst-gentoo-overlay/tree/master/dev-db/pgpool2
> 
> On 04.12.2014 13:35, Muhammad Usama wrote:
>> Hi
>>
>> I have found the problem and pushed the fix for this memory leak in
>> master and 3.4 branch.
>>
>> http://git.postgresql.org/gitweb/?p=pgpool2.git;a=commit;h=2636236af59b90f7e61054518607ca506bb50135
>>
>> Thanks
>> Kind regards,
>> Muhammad Usama
>>
>> On Wed, Dec 3, 2014 at 1:03 PM, Christian Affolter
>> <c.affolter at stepping-stone.ch <mailto:c.affolter at stepping-stone.ch>> wrote:
>>
>>     Great, thanks a lot for looking into it.
>>
>>     Regards
>>     Christian
>>
>>     On 03.12.2014 00:53, Tatsuo Ishii wrote:
>>     > I was able to reproduce the problem with 3.4.0
>>     >
>>     > 1) run pgbench -i
>>     > 2) run pgbench -T 600  -S -c 1 -M extended test
>>     > 3) run ps x as pgpool user and find pgpool process which is bound
>>     to the pgbench session #2
>>     > 4) run ps and watch the process size like 'while true; do ps l
>>     22942; sleep 1; done'
>>     >
>>     > I see in #4, the process size increases rapidly:
>>     > 1  1000 22942 22432  20   0 5145776 5109900 -   S    pts/25   
>>      1:14 pgpool: t-i
>>     > F   UID   PID  PPID PRI  NI    VSZ   RSS WCHAN  STAT TTY       
>>     TIME COMMAND
>>     > 1  1000 22942 22432  20   0 5170364 5134368 -   R    pts/25   
>>      1:15 pgpool: t-i
>>     > F   UID   PID  PPID PRI  NI    VSZ   RSS WCHAN  STAT TTY       
>>     TIME COMMAND
>>     > 1  1000 22942 22432  20   0 5194952 5159100 -   S    pts/25   
>>      1:15 pgpool: t-i
>>     > F   UID   PID  PPID PRI  NI    VSZ   RSS WCHAN  STAT TTY       
>>     TIME COMMAND
>>     > 1  1000 22942 22432  20   0 5227736 5187716 -   R    pts/25   
>>      1:16 pgpool: t-i
>>     > F   UID   PID  PPID PRI  NI    VSZ   RSS WCHAN  STAT TTY       
>>     TIME COMMAND
>>     > 1  1000 22942 22432  20   0 5252324 5212448 -   S    pts/25   
>>      1:16 pgpool: t-i
>>     >
>>     > Note that even if I remove '-M extended' part (which means using
>>     > extended protocol, i.e. prepare statements), I see the memory usage
>>     > growing. So it seems this is nothing to do with whether prepared
>>     > statement is used or not.
>>     >
>>     > We will look into this.
>>     >
>>     > Best regards,
>>     > --
>>     > Tatsuo Ishii
>>     > SRA OSS, Inc. Japan
>>     > English: http://www.sraoss.co.jp/index_en.php
>>     > Japanese:http://www.sraoss.co.jp
>>     >
>>     >> Dear pgpool users
>>     >>
>>     >> I'm running two pgpool-II 3.4.0 instances in master/slave streaming
>>     >> replication mode, with enabled watchdog and virtual IP control.
>>     In the
>>     >> backend are two PostgreSQL 9.3.5 servers (one master and one slave)
>>     >> involved. In the frontend are two Wildfly 8.1.0 application servers
>>     >> having a xa-data-source configured, which connects to the VIP of the
>>     >> pgpool instances.
>>     >>
>>     >> After around two days, the memory of the active pgpool-II
>>     instance (the
>>     >> one holding the VIP) gets depleted completely and all the pgpool-II
>>     >> processes together use around 6 GiB of memory until the kernels
>>     >> out-of-memory manager kicks in or one stops the instance manually.
>>     >>
>>     >> The applications running within the Wildfly application servers are
>>     >> proprietary, so I don't have access to the source code. What I see,
>>     >> after turning statement logging on on the PostgreSQL server, is
>>     that the
>>     >> following queries hit the master all two seconds from both servers:
>>     >>
>>     >> postgres[20069]: [86-1] LOG:  execute <unnamed>: select user0_.id as
>>     >> id1_20_, user0_.company as company2_20_, user0_.created as
>>     created3_20_,
>>     >> user0_.credentials_id as credent10_20_, user0_.email as email4_20_,
>>     >> user0_.firstName as firstNam5_20_, user0_.lastModified as
>>     lastModi6_20_,
>>     >> user0_.mergedTo as mergedTo7_20_, user0_.name as name8_20_,
>>     >> user0_.organisation as organis11_20_, user0_.phone as phone9_20_ from
>>     >> bcUser user0_ where user0_.email=$1
>>     >> postgres[20069]: [86-2] DETAIL:  parameters: $1 =
>>     'system at example.com <mailto:system at example.com>'
>>     >>
>>     >> The queries are triggered from the HTTP load-balancer's alive-check,
>>     >> which is executed every two seconds on one of the applications
>>     running
>>     >> within the Wildfly servers.
>>     >>
>>     >> Does anyone have an idea why pgpool is allocating all the memory,
>>     or how
>>     >> to further debug this?
>>     >>
>>     >> It would also be very helpful if anyone having a similar working
>>     setup
>>     >> (Wildfly or JBoss) could share the data-source settings.
>>     >>
>>     >> There was a similar thread (3162 - Memory leaks) on the mailing list
>>     >> around September [1].
>>     >>
>>     >>
>>     >> Attached you will find an anonymised pgpool-II and xa-data-source
>>     >> configuration, please let me know if you need more.
>>     >>
>>     >>
>>     >> Many thanks in advance
>>     >> Christian
>>     >>
>>     >>
>>     >>
>>     >> [1]
>>     >>
>>     http://www.pgpool.net/pipermail/pgpool-general/2014-September/003204.html