[pgpool-general: 9518] Re: Odd pgpool behavior, help debugging

Bo Peng pengbo at sraoss.co.jp
Mon Jun 16 09:56:57 JST 2025


Hi,

> when the java app starts up pgpool immediately becomes un usable, if I 
> try to connect from the pgpool server with:
>
> psql -h localhost PRODRPT

Since "num_init_children" is set to 96, the maximum number of concurrent connections Pgpool-II can handle is 96.

From the "ps" command output, it appears that there were already 96 idle connections, which likely prevented you from connecting via the psql command.

It seems that your application uses connection pooling. In that case, it should reuse cached connections to Pgpool-II instead of opening new connections each time.
If the application is not reusing cached connections, please check whether any errors are occurring on the application side.
If your application requires more than 96 connections, consider increasing the "num_init_children" parameter.

________________________________________
差出人: pgpool-general <pgpool-general-bounces at pgpool.net> が Sbob <sbob at quadratum-braccas.com> の代理で送信
送信: 2025 年 6 月 14 日 (土曜日) 6:08
宛先: PgPool General <pgpool-general at pgpool.net>
件名: [pgpool-general: 9516] Odd pgpool behavior, help debugging


All;


I have setup pgpool for a client that runs a hefty java app and creates 
lots of connections


I have max_connections on the backend databases set to 1550, the db 
servers have 256GB of memory

The pgpool server has 128G of memory and has the following key settings:

backend_clustering_mode = 'streaming_replication'
listen_addresses = '*'
port = 5432
pcp_listen_addresses = '*'
enable_pool_hba = off
pool_passwd = ''
allow_clear_text_frontend_auth = on
num_init_children = 96
max_pool = 8
load_balance_mode = on
ignore_leading_white_space = on
statement_level_load_balance = on


when the java app starts up pgpool immediately becomes un usable, if I 
try to connect from the pgpool server with:

psql -h localhost PRODRPT


it just hangs and never connects


If I run a ps -ef and grep for pgpool I see this (see below)

Can anyone help me debug this?


Thanks in advance


$ ps -ef | grep pgpool
postgres  320758       1  0 20:44 ?        00:00:00 pgpool -D
postgres  320759  320758  0 20:44 ?        00:00:00 pgpool: PgpoolLogger
postgres  320761  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.45(48116) idle
postgres  320762  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.5.178(51002) idle
postgres  320763  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.6.59(32826) idle
postgres  320764  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.45(48086) idle
postgres  320765  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.45(48148) idle
postgres  320766  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.5.21(46486) idle
postgres  320767  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.5.21(33044) idle
postgres  320768  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.145.59.15(58644) idle
postgres  320769  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.5.21(46458) idle
postgres  320770  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.5.21(46470) idle
postgres  320771  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.145.59.15(58642) idle
postgres  320772  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.145.59.15(58647) idle
postgres  320773  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.45(48090) idle
postgres  320774  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.45(48190) idle
postgres  320775  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.6.59(32802) idle
postgres  320776  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.145.59.15(58645) idle
postgres  320777  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53942) idle
postgres  320778  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.45(48134) idle
postgres  320779  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.5.178(54412) idle
postgres  320780  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.6.59(32814) idle
postgres  320781  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.5.21(33022) idle
postgres  320782  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.237(58640) idle
postgres  320783  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.237(58660) idle
postgres  320784  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.45(48100) idle
postgres  320785  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.45(48174) idle
postgres  320786  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.145.59.15(58646) idle
postgres  320787  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.5.21(33030) idle
postgres  320788  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.5.178(51014) idle
postgres  320789  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(54012) idle
postgres  320790  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53868) idle
postgres  320791  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.45(48118) idle
postgres  320792  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.145.59.15(58640) idle
postgres  320793  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.6.59(32786) idle
postgres  320794  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.45(48200) idle
postgres  320795  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.145.59.15(58649) idle
postgres  320796  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53894) idle
postgres  320797  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.5.178(54400) idle
postgres  320798  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53920) idle
postgres  320799  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.45(48070) idle
postgres  320800  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53926) idle
postgres  320801  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53794) idle
postgres  320802  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53986) idle
postgres  320803  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.145.59.15(58643) idle
postgres  320804  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.145.59.15(58641) idle
postgres  320805  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53972) idle
postgres  320806  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.45(48046) idle
postgres  320807  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.140(40856) idle
postgres  320808  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.5.21(46478) idle
postgres  320809  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.145.59.15(58648) idle
postgres  320810  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.237(58618) idle
postgres  320811  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53844) idle
postgres  320812  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53904) idle
postgres  320813  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53780) idle
postgres  320814  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53950) idle
postgres  320815  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53800) idle
postgres  320816  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.237(58626) idle
postgres  320817  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53958) idle
postgres  320818  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53836) idle
postgres  320819  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53886) idle
postgres  320820  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.45(48096) idle
postgres  320821  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.45(48030) idle
postgres  320822  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.140(40868) idle
postgres  320823  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53810) idle
postgres  320824  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.45(48140) idle
postgres  320825  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53768) idle
postgres  320826  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53848) idle
postgres  320827  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53884) idle
postgres  320828  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53750) idle
postgres  320829  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(54002) idle
postgres  320830  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53826) idle
postgres  320831  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.45(48056) idle
postgres  320832  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.59(36696) idle
postgres  320833  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.59(36686) idle
postgres  320834  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.59(36732) idle
postgres  320835  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53852) idle
postgres  320836  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.6.59(32832) idle
postgres  320837  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.59(36654) idle
postgres  320838  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.59(36648) idle
postgres  320839  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.45(48082) idle
postgres  320840  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.45(48128) idle
postgres  320841  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.59(36656) idle
postgres  320842  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.45(48160) idle
postgres  320843  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.45(48054) idle
postgres  320844  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.59(36720) idle
postgres  320845  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.7.237(58604) idle
postgres  320846  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.5.21(46450) idle
postgres  320847  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53758) idle
postgres  320848  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53880) idle
postgres  320849  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.140(40876) idle
postgres  320850  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.5.21(46460) idle
postgres  320851  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53764) idle
postgres  320852  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53814) idle
postgres  320853  320758  0 20:44 ?        00:00:00 pgpool: user2 
PRODRPT 192.22.7.218(53816) idle
postgres  320854  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.59(36712) idle
postgres  320855  320758  0 20:44 ?        00:00:00 pgpool: user3 
PRODRPT 192.22.6.59(36670) idle
postgres  320856  320758  0 20:44 ?        00:00:00 pgpool: user1 
PRODRPT 192.22.7.237(58644) idle
postgres  320857  320758  0 20:44 ?        00:00:00 pgpool: PCP: wait 
for connection request
postgres  320858  320758  0 20:44 ?        00:00:00 pgpool: worker process
postgres  320859  320758  0 20:44 ?        00:00:00 pgpool: health check 
process(0)
postgres  320860  320758  0 20:44 ?        00:00:00 pgpool: health check 
process(1)
postgres  320881  320710  0 20:47 pts/1    00:00:00 grep --color=auto pgpool



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