[pgpool-general: 2842] Re: Issue with pgpool health check timeout
Shyalika Benthotage
shyalika_benthotage at dialog.com.au
Fri May 16 15:29:26 JST 2014
Hi,
Thanks, now I see why it is not honouring the timeout. I am trying to solve an issue in our production (in AWS) where we had 5 failovers during the last 2 months and every time we believe the DB was working properly. So our guess is it had some glitch in the network so it timed out.
I believe we should try increasing the retry delay so that the 2nd check would return as healthy.
Thanks & Regards,
Shyalika
-----Original Message-----
From: Tatsuo Ishii [mailto:ishii at postgresql.org]
Sent: Friday, 16 May 2014 12:24 PM
To: Shyalika Benthotage
Cc: pgpool-general at pgpool.net; ishii at postgresql.org
Subject: Re: [pgpool-general: 2835] Issue with pgpool health check timeout
Because select(2) time out is counted as an error.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp
> So my question is, why did it timeout too soon without waiting for 10 seconds? Please check my log below
>
>
>
> 2014-05-13 12:14:43 DEBUG: pid 15822: health_check: 0 th DB node status: 1
>
> 2014-05-13 12:14:44 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
> 2014-05-13 12:14:44 ERROR: pid 15822: connect_inet_domain_socket: select() timed out
>
> 2014-05-13 12:14:44 ERROR: pid 15822: make_persistent_db_connection: connection to 10.0.0.5(5432) failed
>
> 2014-05-13 12:14:44 DEBUG: pid 15822: health_check: 0 th DB node status: 1
>
> 2014-05-13 12:14:45 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
> 2014-05-13 12:14:45 ERROR: pid 15822: connect_inet_domain_socket: select() timed out
>
> 2014-05-13 12:14:45 ERROR: pid 15822: make_persistent_db_connection: connection to 10.0.0.5(5432) failed
>
> 2014-05-13 12:14:45 ERROR: pid 15822: health check failed. 0 th host 10.0.0.5 at port 5432 is down
>
> 2014-05-13 12:14:45 DEBUG: pid 15822: health check: clearing alarm
>
> 2014-05-13 12:14:45 DEBUG: pid 15822: health check: clearing alarm
>
> 2014-05-13 12:14:45 LOG: pid 15822: health check retry sleep time: 2 second(s)
>
> 2014-05-13 12:14:46 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
> 2014-05-13 12:14:47 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
> 2014-05-13 12:14:47 DEBUG: pid 15822: retrying 1 th health checking
>
> 2014-05-13 12:14:47 DEBUG: pid 15822: health check: clearing alarm
>
> 2014-05-13 12:14:47 DEBUG: pid 15822: health_check: 0 th DB node status: 1
>
> 2014-05-13 12:14:48 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
> 2014-05-13 12:14:48 ERROR: pid 15822: connect_inet_domain_socket: select() timed out
>
> 2014-05-13 12:14:48 ERROR: pid 15822: make_persistent_db_connection: connection to 10.0.0.5(5432) failed
>
> 2014-05-13 12:14:48 ERROR: pid 15822: health check failed. 0 th host 10.0.0.5 at port 5432 is down
>
> 2014-05-13 12:14:48 DEBUG: pid 15822: health check: clearing alarm
>
> 2014-05-13 12:14:48 DEBUG: pid 15822: health check: clearing alarm
>
> 2014-05-13 12:14:48 LOG: pid 15822: health check retry sleep time: 2 second(s)
>
> 2014-05-13 12:14:49 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
> 2014-05-13 12:14:50 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
> 2014-05-13 12:14:50 DEBUG: pid 15822: retrying 2 th health checking
>
> 2014-05-13 12:14:50 DEBUG: pid 15822: health check: clearing alarm
>
> 2014-05-13 12:14:50 DEBUG: pid 15822: health_check: 0 th DB node status: 1
>
> 2014-05-13 12:14:51 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
> 2014-05-13 12:14:51 ERROR: pid 15822: connect_inet_domain_socket: select() timed out
>
> 2014-05-13 12:14:51 ERROR: pid 15822: make_persistent_db_connection: connection to 10.0.0.5(5432) failed
>
> 2014-05-13 12:14:51 ERROR: pid 15822: health check failed. 0 th host 10.0.0.5 at port 5432 is down
>
> 2014-05-13 12:14:51 DEBUG: pid 15822: health check: clearing alarm
>
> 2014-05-13 12:14:51 DEBUG: pid 15822: health check: clearing alarm
>
> 2014-05-13 12:14:51 LOG: pid 15822: set 0 th backend down status
>
> 2014-05-13 12:14:51 DEBUG: pid 15822: failover_handler called
>
> 2014-05-13 12:14:51 DEBUG: pid 15822: failover_handler: starting to select new master node
>
>
>
> Thanks & Regards,
>
> Shyalika
>
>
>
> -----Original Message-----
> From: Tatsuo Ishii [mailto:ishii at postgresql.org]
> Sent: Friday, 16 May 2014 12:16 PM
> To: Shyalika Benthotage
> Cc: pgpool-general at pgpool.net
> Subject: Re: [pgpool-general: 2835] Issue with pgpool health check timeout
>
>
>
> From: Shyalika Benthotage <shyalika_benthotage at dialog.com.au<mailto:shyalika_benthotage at dialog.com.au>>
>
> Subject: RE: [pgpool-general: 2835] Issue with pgpool health check timeout
>
> Date: Fri, 16 May 2014 02:11:27 +0000
>
> Message-ID: <0C34193B8C9D1249A95AD902CCF181CF14CB66AD at otwdgmxbox01.dialoggroup.internal<mailto:0C34193B8C9D1249A95AD902CCF181CF14CB66AD at otwdgmxbox01.dialoggroup.internal>>
>
>
>
>> Hi Ishii,
>
>>
>
>> Thanks for the quick reply. I tested the pgpool settings using a DROP rule in iptables. I.e. the DROP rule will silently drop data packets without sending a response to the sender, making the sender to wait and then the request to time out. So I believe in this case the network related system call does not actually return so it should time out. Am I correct?
>
>
>
> Yes,correct. More precisely,
>
>
>
> non blocking connect(2) issued then select(2) waits for something comes in:
>
>>> 2014-05-13 12:14:43 DEBUG: pid 15822: health_check: 0 th DB node
>
>
>
> Then select(2) timed out because there is 1 second time out set in the select(2) parameter.
>
>>> 2014-05-13 12:14:44 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
>
>
>> Thanks & Regards,
>
>> Shyalika
>
>>
>
>> -----Original Message-----
>
>> From: Tatsuo Ishii [mailto:ishii at postgresql.org]
>
>> Sent: Friday, 16 May 2014 10:17 AM
>
>> To: Shyalika Benthotage
>
>> Cc: pgpool-general at pgpool.net<mailto:pgpool-general at pgpool.net>
>
>> Subject: Re: [pgpool-general: 2835] Issue with pgpool health check
>
>> timeout
>
>>
>
>>> Hi,
>
>>>
>
>>> We have configured pgpool 3.3 for our PostgreSQL db in aws. And using the healthcheck parameters as below.
>
>>>
>
>>> health_check_period = 40
>
>>> health_check_timeout = 10
>
>>> health_check_max_retries = 2
>
>>> health_check_retry_delay = 2
>
>>>
>
>>> I am trying to test this by using an iptables rule in the active server. When I add a drop rule to the PostgreSQL db port it does trigger a timeout but I think it timeout too soon. I.e. according to my understanding it should wait for the time period specified in "health_check_timeout " in this case, but actually times out in less than a second.(Please see the log below). Shouldn't it wait for 10 secs before time out or is my understanding incorrect.
>
>>
>
>> No. health_check_timeout is a timeout before network related system calls returns. If any of system calls returns error immediately, it is possible that it detects error less than 10 seconds.
>
>>
>
>>> Please note that I checked my DROP rule with telnet and it takes 60 seconds to time out.
>
>>> I have restarted pgpool every time I tested this (I know just
>
>>> reloading would do)
>
>>>
>
>>> I have enabled debug mode just to check this.
>
>>>
>
>>> 2014-05-13 12:14:43 DEBUG: pid 15822: health_check: 0 th DB node
>
>>> status: 1
>
>>> 2014-05-13 12:14:44 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
>>> 2014-05-13 12:14:44 ERROR: pid 15822: connect_inet_domain_socket:
>
>>> select() timed out
>
>>> 2014-05-13 12:14:44 ERROR: pid 15822: make_persistent_db_connection:
>
>>> connection to 10.0.0.5(5432) failed
>
>>> 2014-05-13 12:14:44 DEBUG: pid 15822: health_check: 0 th DB node
>
>>> status: 1
>
>>> 2014-05-13 12:14:45 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
>>> 2014-05-13 12:14:45 ERROR: pid 15822: connect_inet_domain_socket:
>
>>> select() timed out
>
>>> 2014-05-13 12:14:45 ERROR: pid 15822: make_persistent_db_connection:
>
>>> connection to 10.0.0.5(5432) failed
>
>>> 2014-05-13 12:14:45 ERROR: pid 15822: health check failed. 0 th host
>
>>> 10.0.0.5 at port 5432 is down
>
>>> 2014-05-13 12:14:45 DEBUG: pid 15822: health check: clearing alarm
>
>>> 2014-05-13 12:14:45 DEBUG: pid 15822: health check: clearing alarm
>
>>> 2014-05-13 12:14:45 LOG: pid 15822: health check retry sleep time: 2
>
>>> second(s)
>
>>> 2014-05-13 12:14:46 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
>>> 2014-05-13 12:14:47 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
>>> 2014-05-13 12:14:47 DEBUG: pid 15822: retrying 1 th health checking
>
>>> 2014-05-13 12:14:47 DEBUG: pid 15822: health check: clearing alarm
>
>>> 2014-05-13 12:14:47 DEBUG: pid 15822: health_check: 0 th DB node
>
>>> status: 1
>
>>> 2014-05-13 12:14:48 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
>>> 2014-05-13 12:14:48 ERROR: pid 15822: connect_inet_domain_socket:
>
>>> select() timed out
>
>>> 2014-05-13 12:14:48 ERROR: pid 15822: make_persistent_db_connection:
>
>>> connection to 10.0.0.5(5432) failed
>
>>> 2014-05-13 12:14:48 ERROR: pid 15822: health check failed. 0 th host
>
>>> 10.0.0.5 at port 5432 is down
>
>>> 2014-05-13 12:14:48 DEBUG: pid 15822: health check: clearing alarm
>
>>> 2014-05-13 12:14:48 DEBUG: pid 15822: health check: clearing alarm
>
>>> 2014-05-13 12:14:48 LOG: pid 15822: health check retry sleep time: 2
>
>>> second(s)
>
>>> 2014-05-13 12:14:49 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
>>> 2014-05-13 12:14:50 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
>>> 2014-05-13 12:14:50 DEBUG: pid 15822: retrying 2 th health checking
>
>>> 2014-05-13 12:14:50 DEBUG: pid 15822: health check: clearing alarm
>
>>> 2014-05-13 12:14:50 DEBUG: pid 15822: health_check: 0 th DB node
>
>>> status: 1
>
>>> 2014-05-13 12:14:51 LOG: pid 15857: connect_inet_domain_socket: select() timed out. retrying...
>
>>> 2014-05-13 12:14:51 ERROR: pid 15822: connect_inet_domain_socket:
>
>>> select() timed out
>
>>> 2014-05-13 12:14:51 ERROR: pid 15822: make_persistent_db_connection:
>
>>> connection to 10.0.0.5(5432) failed
>
>>> 2014-05-13 12:14:51 ERROR: pid 15822: health check failed. 0 th host
>
>>> 10.0.0.5 at port 5432 is down
>
>>> 2014-05-13 12:14:51 DEBUG: pid 15822: health check: clearing alarm
>
>>> 2014-05-13 12:14:51 DEBUG: pid 15822: health check: clearing alarm
>
>>> 2014-05-13 12:14:51 LOG: pid 15822: set 0 th backend down status
>
>>> 2014-05-13 12:14:51 DEBUG: pid 15822: failover_handler called
>
>>> 2014-05-13 12:14:51 DEBUG: pid 15822: failover_handler: starting to
>
>>> select new master node
>
>>>
>
>>> I even tried setting health_check_timeout to 0 to see whether it defaults to TCP/IP timeout. No difference.
>
>>>
>
>>> Regards,
>
>>> Shyalika
>
>>>
More information about the pgpool-general
mailing list