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Hello,<div><br></div><div>We've also experienced this problem with 3.4.3 with postgres 9.4. The connections pile up on the backend as well and eventually hit the max_connections limit causing pgpool to failover to another node.</div><div><br></div><div>The only way we were able to work around it is to disable the pooling of pgpool, but that looses the main advantage of pgpool.</div><div><pre style="white-space: pre-wrap;">connection_cache = off</pre></div><div><br><br>On 04.01.2016 10:00, Tatsuo Ishii wrote:<br>
>>>>>>> On 31.12.2015 10:50, Tatsuo Ishii wrote:<br>
>>>>>>>>> Yes, reconfigured. Keep you up2date. Any fix for the logic possible?<br>
>>>>>>>> Yes, I'm thinking now.<br>
>>>>>>> Still hangs even with child_max_connections = 0, same stack trace.<br>
>>>>>> Too bad. I'm going to look for other causes if any.<br>
>>>>> I remebered this:<br>
>>>>><br>
>>>>> <a href="http://git.postgresql.org/gitweb/?p=pgpool2.git;a=commit;h=78d2fe3fd" target="_blank">http://git.postgresql.org/gitweb/?p=pgpool2.git;a=commit;h=78d2fe3fd</a><br>
>>>>> 82b4d2ee90e1369be8dd583196fd36e<br>
>>>>><br>
>>>>> If you still have the problem after disabling client_idle_limit, the<br>
>>>>> fix is for you.<br>
>>> Sorry, I wanted to say:<br>
>>><br>
>>>> If you do not have the problem after disabling client_idle_limit,<br>
>>>> the fix is for you.<br>
>>>> Thnx, but still happens. Should I try master version or 3.3.7?<br>
>>> That's an option. However, if you like, could you try the fix before<br>
>>> going to 3.3? The patch may fix other code path which trigger the<br>
>>> problem. (or try 3.4-stable head).<br>
>>><br>
>> I tried the fix on the link already, but it didn't help (unless you did forget to attach another fix?).<br>
>><br>
>> Will try 3.4-stable head, then 3.3 if it doesn't help.<br>
<br>
3.4 stable head also has the problem:<br>
(gdb) ba<br>
#0 0x00007f53d6f40d63 in __select_nocancel () from /lib64/libc.so.6<br>
#1 0x000055a2f00669e1 in pool_check_fd (cp=cp@entry=0x55a2f05c0a20) at <br>
protocol/pool_process_query.c:970<br>
#2 0x000055a2f0066c86 in pool_check_fd (cp=cp@entry=0x55a2f05c0a20) at <br>
protocol/pool_process_query.c:992<br>
#3 0x000055a2f00a9f7b in pool_read (cp=0x55a2f05c0a20, <br>
buf=buf@entry=0x7ffc811e7137, len=len@entry=1) at utils/pool_stream.c:159<br>
#4 0x000055a2f006f1dc in read_kind_from_backend <br>
(frontend=frontend@entry=0x55a2f05ba270, <br>
backend=backend@entry=0x55a2f05b9210, <br>
decided_kind=decided_kind@entry=0x7ffc811e7537 "E")<br>
at protocol/pool_process_query.c:3618<br>
#5 0x000055a2f0076d79 in ProcessBackendResponse <br>
(frontend=frontend@entry=0x55a2f05ba270, <br>
backend=backend@entry=0x55a2f05b9210, state=state@entry=0x7ffc811e75cc,<br>
num_fields=num_fields@entry=0x7ffc811e75ca) at <br>
protocol/pool_proto_modules.c:2519<br>
#6 0x000055a2f006b1b7 in pool_process_query (frontend=0x55a2f05ba270, <br>
backend=0x55a2f05b9210, reset_request=reset_request@entry=1) at <br>
protocol/pool_process_query.c:302<br>
#7 0x000055a2f0062a9a in backend_cleanup (backend=<optimized out>, <br>
frontend_invalid=frontend_invalid@entry=0 '\000', <br>
frontend=0x55a2f037c4e0 <child_frontend>) at protocol/child.c:442<br>
#8 0x000055a2f0065745 in do_child (fds=fds@entry=0x55a2f05b4440) at <br>
protocol/child.c:238<br>
#9 0x000055a2f004263e in fork_a_child (fds=0x55a2f05b4440, id=3) at <br>
main/pgpool_main.c:678<br>
#10 0x000055a2f0043735 in reaper () at main/pgpool_main.c:2148<br>
#11 0x000055a2f004724b in PgpoolMain (discard_status=<optimized out>, <br>
clear_memcache_oidmaps=<optimized out>) at main/pgpool_main.c:411<br>
#12 0x000055a2f0040d4e in main (argc=<optimized out>, <br>
argv=0x7ffc811ecb28) at main/main.c:310<br>
<br>
Will try 3.3.7.<br>
<br>
BTW: I'm using the following script to get an overview whats happening:<br>
cat watch_pg.sh<br>
#!/usr/bin/env bash<br>
watch -n 1 "ps wwwaux --sort=user,command,pid | grep -v grep | grep -E <br>
'^USER|pgpool|postgres:'"<br>
<br>
Ciao,<br>
Gerhard<br>
<br>
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