<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:10pt"><div><span>Let me explain you my test case where no psql is conneced:<br></span></div><div><br><span></span></div><div><span>1. One Master (5432) and One standby (5433) with pgpool (9999) in SR mode.<br></span></div><div>2. Make Master (5432) down. This will make Standby (5433) as a new Master.<br>3. Recover old Master (5432) as a new Standby.<br>4. Take basebackup of new Master (5433) to create new node (5434).<br>5. Execute pcp_proc_count to note the client PIDs.<br>6. edit pgpool.conf and reload the configuration file.<br>7. Attach the new node (5434)<br>8. Execute pcp_proc_count again to note the client PIDs. These should be same as the PIDs generated in Step5. Right?<br><br></div> <div style="font-family: times new roman, new york, times, serif; font-size: 10pt;"> <div style="font-family: times new roman, new york,
times, serif; font-size: 12pt;"> <font size="2" face="Arial"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Sandeep Thakkar <sandeeptt@yahoo.com><br> <b><span style="font-weight: bold;">To:</span></b> Sandeep Thakkar <sandeeptt@yahoo.com>; Tatsuo Ishii <ishii@postgresql.org> <br><b><span style="font-weight: bold;">Cc:</span></b> "pgpool-general@pgpool.net" <pgpool-general@pgpool.net> <br> <b><span style="font-weight: bold;">Sent:</span></b> Wednesday, December 7, 2011 11:56 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [pgpool-general: 32] Re: [Pgpool-general] pgpool limitations<br> </font> <br>
<div id="yiv1748543301"><div><div style="color:#000;background-color:#fff;font-family:times new roman, new york, times, serif;font-size:10pt;">The test case where I do not have any psql client connected, passes on some platforms (Sparc) and fails randomly on other platforms (Linux32, Solaris-x86). Could this be related to the system speed? Or something else? I'm unable to figure out the cause yet. As per your explanation, the pgpool clients should be restarted in this case, right?<br><br><div style="font-family:times new roman, new york, times, serif;font-size:10pt;"> <div style="font-family:times new roman, new york, times, serif;font-size:12pt;"> <font size="2" face="Arial"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Sandeep Thakkar <sandeeptt@yahoo.com><br> <b><span style="font-weight:bold;">To:</span></b> Tatsuo Ishii <ishii@postgresql.org> <br><b><span style="font-weight:bold;">Cc:</span></b>
"pgpool-general@pgpool.net"
<pgpool-general@pgpool.net> <br> <b><span style="font-weight:bold;">Sent:</span></b> Monday, December 5, 2011 4:00 PM<br> <b><span style="font-weight:bold;">Subject:</span></b> [pgpool-general: 32] Re: [Pgpool-general] pgpool limitations<br> </font> <br><div id="yiv1748543301"><div><div style="color:#000;background-color:#fff;font-family:times new roman, new york, times, serif;font-size:10pt;"><div><span>Sorry for the confusion. Yes, they are both different test cases. <br></span></div><div><br></div> <div style="font-family:times new roman, new york, times, serif;font-size:10pt;"> <div style="font-family:times new roman, new york, times, serif;font-size:12pt;"> <font size="2" face="Arial"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Tatsuo Ishii <ishii@postgresql.org><br> <b><span style="font-weight:bold;">To:</span></b> sandeeptt@yahoo.com <br><b><span style="font-weight:bold;">Cc:</span></b>
pgpool-general@pgpool.net <br> <b><span style="font-weight:bold;">Sent:</span></b> Monday, December 5, 2011 3:28 PM<br> <b><span style="font-weight:bold;">Subject:</span></b> Re: [pgpool-general: 28] Re: [Pgpool-general] pgpool limitations<br> </font> <br>
I want to clarify. You said you have one connected psql client, but<br>now you are saying that no connected psql client. Are they different<br>test cases?<br>--<br>Tatsuo Ishii<br>SRA OSS, Inc. Japan<br>English: http://www.sraoss.co.jp/index_en.php<br>Japanese: http://www.sraoss.co.jp<br><br>> Well, what I have seen is that if there is no established connection and all pgpool client processes are idle.. and in post attachment of the new client, sometimes all pgpool clients are restarted and sometimes they are not at all.. why this random behaviour?<br>> <br>> <br>> <br>> ________________________________<br>> From: Sandeep Thakkar <<a rel="nofollow" ymailto="mailto:sandeeptt@yahoo.com" target="_blank" href="mailto:sandeeptt@yahoo.com">sandeeptt@yahoo.com</a>><br>> To: Tatsuo Ishii <<a rel="nofollow" ymailto="mailto:ishii@postgresql.org" target="_blank"
href="mailto:ishii@postgresql.org">ishii@postgresql.org</a>> <br>> Cc: "<a rel="nofollow" ymailto="mailto:pgpool-general@pgpool.net" target="_blank" href="mailto:pgpool-general@pgpool.net">pgpool-general@pgpool.net</a>" <<a rel="nofollow" ymailto="mailto:pgpool-general@pgpool.net" target="_blank" href="mailto:pgpool-general@pgpool.net">pgpool-general@pgpool.net</a>> <br>> Sent: Monday, December 5, 2011 2:39 PM<br>> Subject: [pgpool-general: 28] Re: [Pgpool-general] pgpool limitations<br>> <br>> <br>> Oh.. I see.. Why then it behaves randomly?<br>> <br>> <br>> I did the following test:<br>> the number of pgpool client processes are 32 and only one of them is connected to psql client (one session), and I add new node (take basebackup, create recovery.conf, start new server, get the client PIDs using pcp_proc_count, edit pgpool.conf, reload pgpool.conf, pcp_attach_node, get the client PIDs again using
pcp_proc_count).. and I found that when the psql client exits, only one pgpool client gets restarted and now has new PID... rest of the idle pgpool client processes had the same PIDs after
attaching the node.<br>> <br>> <br>> <br>> <br>> ________________________________<br>> From: Tatsuo Ishii <<a rel="nofollow" ymailto="mailto:ishii@postgresql.org" target="_blank" href="mailto:ishii@postgresql.org">ishii@postgresql.org</a>><br>> To: <a rel="nofollow" ymailto="mailto:sandeeptt@yahoo.com" target="_blank" href="mailto:sandeeptt@yahoo.com">sandeeptt@yahoo.com</a> <br>> Cc: <a rel="nofollow" ymailto="mailto:pgpool-general@pgpool.net" target="_blank" href="mailto:pgpool-general@pgpool.net">pgpool-general@pgpool.net</a> <br>> Sent: Monday, December 5, 2011 11:59 AM<br>> Subject: Re: [pgpool-general: 8] Re: [Pgpool-general] pgpool limitations<br>> <br>> Good catch. I forgot about this. From pgpool-II 3.1, in streaming<br>> replication mode, after failback event, existing sessions are not<br>> disconnected any more. However afte the session exits, pgpool child<br>> restarts to take
care of failback node info to, for example, use the<br>> node for load balancing.<br>>
--<br>> Tatsuo Ishii<br>> SRA OSS, Inc. Japan<br>> English: <a rel="nofollow" target="_blank" href="http://www.sraoss.co.jp/index_en.php">http://www.sraoss.co.jp/index_en.php</a><br>> Japanese: <a rel="nofollow" target="_blank" href="http://www.sraoss.co.jp">http://www.sraoss.co.jp</a><br>> <br>>> I just see some additional statements like "failback event found. restart myself"...<br>>> <br>>> 2011-11-30 10:39:46 LOG: pid 7398: find_primary_node_repeatedly: waiting for finding a primary node<br>>> 2011-11-30 10:39:46 LOG: pid 7398: find_primary_node: primary node id is 1<br>>> 2011-11-30 10:39:46 LOG: pid 7398: failover: set new primary node: 1<br>>> 2011-11-30 10:39:46 LOG: pid 7398: failover: set new master node: 0<br>>> 2011-11-30 10:39:46<br>> LOG: pid 7398: failback done. reconnect host localhost(5447)<br>>> 2011-11-30
10:39:46 LOG: pid
7532: worker process received restart request<br>>> 2011-11-30 10:39:47 LOG: pid 7565: pcp child process received restart request<br>>> 2011-11-30 10:39:47 LOG: pid 7398: worker child 7532 exits with status 256<br>>> 2011-11-30 10:39:47 LOG: pid 7398: fork a new worker child pid 7648<br>>> 2011-11-30 10:44:10 LOG: pid 7533: do_child: failback event found. restart myself.<br>>> 2011-11-30 10:44:10 LOG: pid 7534: do_child: failback event found. restart myself.<br>>> ....<br>>> ....<br>>> <br>>> <br>>> <br>>> <br>>> ________________________________<br>>> From: Tatsuo Ishii <<a rel="nofollow" ymailto="mailto:ishii@postgresql.org" target="_blank" href="mailto:ishii@postgresql.org">ishii@postgresql.org</a>><br>>> To: <a rel="nofollow" ymailto="mailto:sandeeptt@yahoo.com" target="_blank"
href="mailto:sandeeptt@yahoo.com">sandeeptt@yahoo.com</a> <br>>> Cc:
<a rel="nofollow" ymailto="mailto:pgpool-general@pgpool.net" target="_blank" href="mailto:pgpool-general@pgpool.net">pgpool-general@pgpool.net</a> <br>>> Sent: Tuesday, November 29, 2011 3:24 PM<br>>> Subject: Re: [pgpool-general: 8] Re: [Pgpool-general] pgpool limitations<br>>> <br>>> I can't think of any other reasons. Can you find anything special in<br>>> the pgpool log when pgpool child exits?<br>>> --<br>>> Tatsuo Ishii<br>>> SRA OSS, Inc. Japan<br>>> English: <a rel="nofollow" target="_blank" href="http://www.sraoss.co.jp/index_en.php">http://www.sraoss.co.jp/index_en.php</a><br>>> Japanese: <a rel="nofollow" target="_blank" href="http://www.sraoss.co.jp">http://www.sraoss.co.jp</a><br>>> <br>>>> client_idle_limit is set to '0'. Here is the other related settings:<br>>>> ....<br>>>> pcp_timeout = 10<br>>>> num_init_children =
32<br>>>> max_pool = 4<br>>>> child_life_time
=<br>> 300<br>>>> connection_life_time = 0<br>>>> child_max_connections = 0<br>>>> client_idle_limit = 0<br>>>> ....<br>>>> <br>>>> <br>>>> <br>>>> ________________________________<br>>>> From: Tatsuo Ishii <<a rel="nofollow" ymailto="mailto:ishii@sraoss.co.jp" target="_blank" href="mailto:ishii@sraoss.co.jp">ishii@sraoss.co.jp</a>><br>>>> To: <a rel="nofollow" ymailto="mailto:sandeeptt@yahoo.com" target="_blank" href="mailto:sandeeptt@yahoo.com">sandeeptt@yahoo.com</a> <br>>>> Cc: <a rel="nofollow" ymailto="mailto:singh.gurjeet@gmail.com" target="_blank" href="mailto:singh.gurjeet@gmail.com">singh.gurjeet@gmail.com</a>; <a rel="nofollow" ymailto="mailto:pgpool-general@pgfoundry.org" target="_blank" href="mailto:pgpool-general@pgfoundry.org">pgpool-general@pgfoundry.org</a>; <a rel="nofollow"
ymailto="mailto:pgpool-hackers@pgfoundry.org" target="_blank" href="mailto:pgpool-hackers@pgfoundry.org">pgpool-hackers@pgfoundry.org</a> <br>>>> Sent: Wednesday, November 23, 2011
8:21 PM<br>>>> Subject: Re: [Pgpool-general] pgpool<br>> limitations<br>>>> <br>>>> One possibility is client_idle_limit.<br>>>> --<br>>>> Tatsuo Ishii<br>>>> SRA OSS, Inc. Japan<br>>>> English: <a rel="nofollow" target="_blank" href="http://www.sraoss.co.jp/index_en.php">http://www.sraoss.co.jp/index_en.php</a><br>>>> Japanese: <a rel="nofollow" target="_blank" href="http://www.sraoss.co.jp">http://www.sraoss.co.jp</a><br>>>> <br>>>>> I have found that sometimes the client connections get disconnected and the new ones are established. What I do is I get the PIDs using "pcp_proc_count" before running "pcp_attach_node" and then run "pcp_proc_count" to check if the PIDs remain same. I found that the behaviour is random. When can this happen?<br>>>>> <br>>>>> <br>>>>>
________________________________<br>>>>> From: Tatsuo Ishii
<<a rel="nofollow" ymailto="mailto:ishii@sraoss.co.jp" target="_blank" href="mailto:ishii@sraoss.co.jp">ishii@sraoss.co.jp</a>><br>>>>> To: <a rel="nofollow" ymailto="mailto:singh.gurjeet@gmail.com" target="_blank" href="mailto:singh.gurjeet@gmail.com">singh.gurjeet@gmail.com</a> <br>>>>> Cc: <a rel="nofollow" ymailto="mailto:pgpool-general@pgfoundry.org" target="_blank" href="mailto:pgpool-general@pgfoundry.org">pgpool-general@pgfoundry.org</a>; <a rel="nofollow" ymailto="mailto:pgpool-hackers@pgfoundry.org" target="_blank" href="mailto:pgpool-hackers@pgfoundry.org">pgpool-hackers@pgfoundry.org</a> <br>>>>> Sent: Thursday, August 11, 2011 6:11 AM<br>>>>> Subject: Re: [Pgpool-general] pgpool limitations<br>>>>> <br>>>>>>> > > Is there something in the works to enable this, or is this feature<br>>>>>>> still in<br>>>>>>>
> > design phase? If it is already being/been developed, I wish to know if<br>>>>>>>
this<br>>>>>>> > > can be back-patched to a point release of pgpool 3.0.x.<br>>>>>>> ><br>>>>>>> > It has been already in<br>> pgpool-II 3.1 alpha version.<br>>>>>>> > Currently there's no plan to back-patching to 3.0.x.<br>>>>>>><br>>>>>>> I certainly hope we won't backpatch a new feature. That would be insane.<br>>>>>>><br>>>>>> <br>>>>>> I don't consider this a new feature. I'd say this is unexpected side-effect<br>>>>>> (a.k.a bug) of pcp_attach_node, since nowhere in the docs does is say that<br>>>>>> invoking pcp_attach_node would drop all client connections.<br>>>>> <br>>>>> This behavior has not been changed since pcp_attach_node was born in<br>>>>> 2006. Moreover, the enhancement in 3.1 is only for
steaming<br>>>>> replication mode. Other modes including replication mode does not take<br>>>>> advantage of this.<br>>>>> --<br>>>>> Tatsuo Ishii<br>>>>> SRA OSS, Inc. Japan<br>>>>> English: <a rel="nofollow" target="_blank" href="http://www.sraoss.co.jp/index_en.php">http://www.sraoss.co.jp/index_en.php</a><br>>>>> Japanese: <a rel="nofollow" target="_blank" href="http://www.sraoss.co.jp">http://www.sraoss.co.jp</a><br>>>>> _______________________________________________<br>>>>> Pgpool-general mailing list<br>>>>> <a rel="nofollow" ymailto="mailto:Pgpool-general@pgfoundry.org" target="_blank" href="mailto:Pgpool-general@pgfoundry.org">Pgpool-general@pgfoundry.org</a><br>>>>> http://pgfoundry.org/mailman/listinfo/pgpool-general<br>> <br>> <br>> <br>> _______________________________________________<br>>
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