<div dir="auto">Hi Tatsuo,<div dir="auto"><br></div><div dir="auto">I am using Pgpool v4.1.1.</div><div dir="auto"><br></div><div dir="auto">I have seen similiar behaviour in v4.0.9 as well.</div><div dir="auto"><br></div><div dir="auto">Thanks and Regards,</div><div dir="auto">Nikhil</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Aug 30, 2020, 13:11 Tatsuo Ishii <<a href="mailto:ishii@sraoss.co.jp">ishii@sraoss.co.jp</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Ok, I have tried with your test data and pgpool settings. Also I added<br>
log_disconnections to postgresql.conf so that when Pgpool-II<br>
disconnects backend. However I was not able to reproduce your<br>
problem. Pgpool-II worked as expected (10 seconds after the test<br>
script ends, connection was terminated on all backends).<br>
<br>
What version of Pgpool-II are you using?<br>
<br>
> Hi Tatsuo,<br>
> <br>
> <br>
> No, because my primary has node ID 0 and standby has node ID 1.<br>
> <br>
> Patch will help if my primary node ID is not 0 rite?<br>
> <br>
> Thanks and Regards,<br>
> Nikhil<br>
> <br>
> <br>
> On Sun, Aug 30, 2020, 12:19 Tatsuo Ishii <<a href="mailto:ishii@sraoss.co.jp" target="_blank" rel="noreferrer">ishii@sraoss.co.jp</a>> wrote:<br>
> <br>
>> Before these tests, have applied the patch?<br>
>><br>
>> > Hi Tatsuo,<br>
>> ><br>
>> ><br>
>> > I have to reopen this issue because after a lot of debugging and reading<br>
>> > documentation on connection_life_time though there is not much of it,<br>
>> this<br>
>> > parameter doesn't work as it should.<br>
>> ><br>
>> > First I want to be correct in my understanding that this parameter<br>
>> > terminates cached backend connections in the database.So, I test a simple<br>
>> > scenario as follows:<br>
>> ><br>
>> > PGPOOL - 128.199.224.132<br>
>> ><br>
>> > *Parameters set for pooling*<br>
>> > serialize_accept=on<br>
>> > child_life_time=0<br>
>> > child_max_connections=0<br>
>> > client_idle_limit=0<br>
>> > connection_life_time=10<br>
>> ><br>
>> > *I am running a mixed.sql file which contain below statements*<br>
>> > BEGIN;<br>
>> > SELECT CURRENT_TIMESTAMP;<br>
>> > INSERT into t1 values(3);<br>
>> > INSERT into t1 values(4);<br>
>> > select pg_sleep(5);<br>
>> > INSERT into t1 values(5);<br>
>> > UPDATE t1 set id=4 where id=5;<br>
>> > END;<br>
>> ><br>
>> > After executing some inserts it will sleep for 5 seconds and then execute<br>
>> > one update and an insert before closing the connection.<br>
>> ><br>
>> ><br>
>> > *1) Status of nodes*<br>
>> > -bash-4.2$ psql -h 128.199.224.132 -p 9999 -U enterprisedb<br>
>> > psql.bin (11.6.13)<br>
>> > Type "help" for help.<br>
>> ><br>
>> > edb=# show pool_nodes;<br>
>> > node_id | hostname | port | status | lb_weight | role |<br>
>> > select_cnt | load_balance_node | replication_delay | replication_state |<br>
>> > replication_syn<br>
>> > c_state | last_status_change<br>
>> ><br>
>> ---------+-----------------+------+--------+-----------+---------+------------+-------------------+-------------------+-------------------+----------------<br>
>> > --------+---------------------<br>
>> > 0 | 128.199.222.92 | 5445 | up | 0.000000 | primary | 0<br>
>> > | false | 0 | |<br>
>> > | 2020-08-30 04:58:24<br>
>> > 1 | 128.199.222.124 | 5445 | up | 1.000000 | standby | 0<br>
>> > | true | 0 | |<br>
>> > | 2020-08-30 04:58:24<br>
>> > (2 rows)<br>
>> ><br>
>> > *2) Running the mixed.sql file*<br>
>> > -bash-4.2$ psql -h 128.199.224.132 -p 9999 -U enterprisedb -f mixed.sql<br>
>> > BEGIN<br>
>> > current_timestamp<br>
>> > ----------------------------------<br>
>> > 30-AUG-20 10:31:47.396527 +05:30<br>
>> > (1 row)<br>
>> ><br>
>> > INSERT 0 1<br>
>> > INSERT 0 1<br>
>> > pg_sleep<br>
>> > ----------<br>
>> ><br>
>> > (1 row)<br>
>> ><br>
>> > INSERT 0 1<br>
>> > UPDATE 1<br>
>> > COMMIT<br>
>> > -bash-4.2$<br>
>> ><br>
>> > *3) pool_pools output shows pgpool (pid - 31560) created one connection<br>
>> to<br>
>> > master(pid - 31550) and one to standby (pid - 28954) *<br>
>> ><br>
>> > edb=# show pool_pools;<br>
>> > pool_pid | start_time | pool_id | backend_id | database |<br>
>> > username | create_time | majorversion | minorversion |<br>
>> > pool_counter | pool_<br>
>> > backendpid | pool_connected<br>
>> ><br>
>> ----------+---------------------+---------+------------+----------+--------------+---------------------+--------------+--------------+--------------+------<br>
>> > -----------+----------------<br>
>> > 31560 | 2020-08-30 04:51:54 | 0 | 0 | edb |<br>
>> > enterprisedb | 2020-08-30 05:01:47 | 3 | 0 | 1<br>
>> > | 31550<br>
>> > | 0<br>
>> > 31560 | 2020-08-30 04:51:54 | 0 | 1 | edb |<br>
>> > enterprisedb | 2020-08-30 05:01:47 | 3 | 0 | 1<br>
>> > | 28954<br>
>> > | 0<br>
>> ><br>
>> > *4) Status of process id 31550 on master.After the run, as seen below on<br>
>> > the database is idle*<br>
>> ><br>
>> > -bash-4.2$ ps -ef |grep 224.132<br>
>> > enterpr+ 31550 9148 0 05:01 ? 00:00:00 postgres: enterprisedb<br>
>> edb<br>
>> > 128.199.224.132[49656] idle<br>
>> ><br>
>> > *5) Status of processid 31560 on pgpool.* *After the run, as seen below<br>
>> > pgpool has released connection as soon as transaction completes*<br>
>> > [root@pgpool-p pgpool4.1]# ps -ef |grep 31560<br>
>> > enterpr+ 31560 31557 0 04:51 ? 00:00:00 pgpool: wait for accept<br>
>> lock<br>
>> ><br>
>> ><br>
>> > *6) After 10 seconds, this cached connection on database should have been<br>
>> > terminated as per my understanding of connection_life_time parameter but<br>
>> as<br>
>> > seen below it has not terminated*<br>
>> > edb=# select * from pg_stat_activity where client_addr<br>
>> ='128.199.224.132';<br>
>> > -[ RECORD 1 ]----+---------------------------------<br>
>> > datid | 67127<br>
>> > datname | edb<br>
>> > pid | 31550<br>
>> > usesysid | 10<br>
>> > usename | enterprisedb<br>
>> > application_name | psql.bin<br>
>> > client_addr | 128.199.224.132<br>
>> > client_hostname |<br>
>> > client_port | 49656<br>
>> > backend_start | 30-AUG-20 10:31:47.380345 +05:30<br>
>> > xact_start |<br>
>> > query_start | 30-AUG-20 10:31:52.411607 +05:30<br>
>> > state_change | 30-AUG-20 10:31:52.411714 +05:30<br>
>> > wait_event_type | Client<br>
>> > wait_event | ClientRead<br>
>> > state | idle<br>
>> > backend_xid |<br>
>> > backend_xmin |<br>
>> > query | DISCARD ALL<br>
>> > backend_type | client backend<br>
>> ><br>
>> > Do not mind the timestamp, it is in IST for the above query.<br>
>> ><br>
>> > *7) From the pgpool logs, it sets the alarm after 10 sec but doesn't<br>
>> really<br>
>> > close the connection after 10 seconds*<br>
>> > Aug 30 05:01:52 Pgpool-p pgpool[*31560*]: [252-2] 2020-08-30 05:01:52:<br>
>> pid<br>
>> > 31560: DETAIL: setting alarm after 10 seconds<br>
>> ><br>
>> > Attaching pgpool logs as well.<br>
>> ><br>
>> ><br>
>> > On Wed, Aug 12, 2020 at 9:02 PM Nikhil Shetty <<a href="mailto:nikhil.dba04@gmail.com" target="_blank" rel="noreferrer">nikhil.dba04@gmail.com</a>><br>
>> > wrote:<br>
>> ><br>
>> >> Hi Tatsuo,<br>
>> >><br>
>> >> Thank you, I will check how this works.<br>
>> >><br>
>> >><br>
>> >> On Tue, Aug 11, 2020 at 5:52 PM Tatsuo Ishii <<a href="mailto:ishii@sraoss.co.jp" target="_blank" rel="noreferrer">ishii@sraoss.co.jp</a>><br>
>> wrote:<br>
>> >><br>
>> >>> Hi Nikhil,<br>
>> >>><br>
>> >>> > Hi Tatsuo,<br>
>> >>> ><br>
>> >>> > We are checking the patch internally before we go ahead and deploy in<br>
>> >>> > production.<br>
>> >>><br>
>> >>> Ok.<br>
>> >>><br>
>> >>> > If I want to set only one of either connection_life_time or<br>
>> >>> > client_idle_limit. What do you recommend? Should I set<br>
>> >>> > client_idle_limit=120 and connection_life_time=0, do you foresee any<br>
>> >>> > effects of these settings for connection pooling?<br>
>> >>><br>
>> >>> In general connection_life_time is better because:<br>
>> >>><br>
>> >>> 1. when client_idle_limit expires, pgpool needs to fork a new process,<br>
>> >>> but connection_life_time does not.<br>
>> >>><br>
>> >>> 2. when client_idle_limit expires, it looses mutiple connection pools<br>
>> >>> (this only applicatable fro max_pool > 1 case) because the<br>
>> >>> connection pools the process hold go away.<br>
>> >>><br>
>> >>> However if you have very short and frequent sessions, more alarm<br>
>> >>> system calls with connection_life_time are required and maybe<br>
>> >>> client_idle_limit wins in this case.<br>
>> >>><br>
>> >>> > Thank you for your time and support.<br>
>> >>> ><br>
>> >>> > Thanks and Regards,<br>
>> >>> > Nikhil<br>
>> >>> ><br>
>> >>> > On Mon, Aug 10, 2020 at 11:58 AM Tatsuo Ishii <<a href="mailto:ishii@sraoss.co.jp" target="_blank" rel="noreferrer">ishii@sraoss.co.jp</a>><br>
>> >>> wrote:<br>
>> >>> ><br>
>> >>> >> Hi Nikhil,<br>
>> >>> >><br>
>> >>> >> I have been investigating if there's any case when<br>
>> >>> >> connection_life_time is not working. Actually it *is*. If primary<br>
>> node<br>
>> >>> >> is not node 0, connection_life_time does not work. Attached is the<br>
>> >>> >> patch to fix that. Please try, if you like.<br>
>> >>> >><br>
>> >>> >> > According to your previous message, corresponding pgpool process<br>
>> was<br>
>> >>> >> > not there, but PostgreSQL backend process were still running. I<br>
>> >>> >> > suspect the backend process was waiting for TCP/IP connection was<br>
>> >>> >> > terminated. But to know what was actually happening, I was waiting<br>
>> >>> for<br>
>> >>> >> > your response.<br>
>> >>> >> ><br>
>> >>> >> >>> "DISCARD ALL" and state idle. I will have to test again to check<br>
>> >>> the<br>
>> >>> >> socket<br>
>> >>> >> >>> status of pid.I will get back on this<br>
>> >>> >> ><br>
>> >>> >> > What was that?<br>
>> >>> >> ><br>
>> >>> >> >> Hi Tatsuo,<br>
>> >>> >> >><br>
>> >>> >> >><br>
>> >>> >> >> Ant reason why connection_idle_limit doesn't remove backend<br>
>> >>> connection<br>
>> >>> >> >> after time limit is crossed<br>
>> >>> >> >><br>
>> >>> >> >> Thanks and Regards,<br>
>> >>> >> >> Nikhil<br>
>> >>> >> >><br>
>> >>> >> >> On Sun, Aug 2, 2020, 12:48 Nikhil Shetty <<a href="mailto:nikhil.dba04@gmail.com" target="_blank" rel="noreferrer">nikhil.dba04@gmail.com</a><br>
>> ><br>
>> >>> >> wrote:<br>
>> >>> >> >><br>
>> >>> >> >>> Hi Tatsuo,<br>
>> >>> >> >>><br>
>> >>> >> >>> I want to correct my statement from previous email:<br>
>> >>> >> >>><br>
>> >>> >> >>> From ps status *I could not see *that the process (18190 and<br>
>> 18193)<br>
>> >>> >> were<br>
>> >>> >> >>> still present on pgpool but the backend process was still<br>
>> present<br>
>> >>> with<br>
>> >>> >> >>> "DISCARD ALL" and state idle. I will have to test again to check<br>
>> >>> the<br>
>> >>> >> socket<br>
>> >>> >> >>> status of pid.I will get back on this<br>
>> >>> >> >>><br>
>> >>> >> >>> On Sun, Aug 2, 2020 at 12:15 PM Nikhil Shetty <<br>
>> >>> <a href="mailto:nikhil.dba04@gmail.com" target="_blank" rel="noreferrer">nikhil.dba04@gmail.com</a>><br>
>> >>> >> >>> wrote:<br>
>> >>> >> >>><br>
>> >>> >> >>>> Hi Tatsuo,<br>
>> >>> >> >>>><br>
>> >>> >> >>>> >> Assuming you executed "show pool_pools" long after<br>
>> 2020-08-01<br>
>> >>> >> >>>> >> 06:21:26, that is very strange because connection_life_time<br>
>> >>> should<br>
>> >>> >> >>>> >> have been already expired. I wonder if pgpool tried to<br>
>> >>> disconnect<br>
>> >>> >> the<br>
>> >>> >> >>>> >> connection but failed. To check what actually happend, can<br>
>> you<br>
>> >>> >> check<br>
>> >>> >> >>>> >> ps status of pgpool process 18190 and 18193?<br>
>> >>> >> >>>><br>
>> >>> >> >>>> >> Also it would be nice you can examine the socket status of<br>
>> >>> >> PostgreSQL<br>
>> >>> >> >>>> >> backend 29321 and 29619, and pgpool socket status of process<br>
>> >>> 18190<br>
>> >>> >> and<br>
>> >>> >> >>>> >> 18193?<br>
>> >>> >> >>>><br>
>> >>> >> >>>> From ps status I could see that the process (18190 and 18193)<br>
>> were<br>
>> >>> >> still<br>
>> >>> >> >>>> present on pgpool. I will have to test again to check the<br>
>> socket<br>
>> >>> >> status of<br>
>> >>> >> >>>> pid.I will get back on this<br>
>> >>> >> >>>><br>
>> >>> >> >>>> Meanwhile, I did some testing of my own for these two<br>
>> parameters(<br>
>> >>> >> >>>> client_idle_limit and connection_life_time ) and their<br>
>> behaviour:<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> *Test:*<br>
>> >>> >> >>>><br>
>> >>> >> >>>> Database IP:128.199.222.92(master)<br>
>> >>> >> >>>> Pgpool IP: 128.199.224.132<br>
>> >>> >> >>>><br>
>> >>> >> >>>> *Scenario1:*<br>
>> >>> >> >>>><br>
>> >>> >> >>>> max_pool=1<br>
>> >>> >> >>>> num_init_children=100<br>
>> >>> >> >>>> serialize_accept=on<br>
>> >>> >> >>>> child_max_connections=0<br>
>> >>> >> >>>> child_life_time=0<br>
>> >>> >> >>>> connection_life_time=60<br>
>> >>> >> >>>> client_idle_limit=0<br>
>> >>> >> >>>><br>
>> >>> >> >>>> *1. Connected to Pgpool and ran a query with \watch 1:*<br>
>> >>> >> >>>> select count(*) from pgbench_accounts ;<br>
>> >>> >> >>>> \watch 1<br>
>> >>> >> >>>> Sat 01 Aug 2020 07:25:54 AM UTC (every 1s)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> count<br>
>> >>> >> >>>> ---------<br>
>> >>> >> >>>> 6000000<br>
>> >>> >> >>>><br>
>> >>> >> >>>> *2. Checking session in database, one session is active from<br>
>> >>> pgpool*<br>
>> >>> >> >>>> Sat 01 Aug 2020 07:26:14 AM UTC<br>
>> >>> (every 1s)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> pid | query | usename<br>
>> |<br>
>> >>> >> >>>> client_addr | count | state<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >><br>
>> >>><br>
>> ------+-----------------------------------------+--------------+-----------------+-------+--------<br>
>> >>> >> >>>> 3420 | select count(*) from pgbench_accounts ; | enterprisedb<br>
>> |<br>
>> >>> >> >>>> 128.199.224.132 | 1 | active<br>
>> >>> >> >>>> (1 row)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> *3. Stopped the query after sometime using Ctrl-C but session<br>
>> is<br>
>> >>> still<br>
>> >>> >> >>>> open*<br>
>> >>> >> >>>> Sat 01 Aug 2020 07:27:35 AM UTC (every 1s)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> count<br>
>> >>> >> >>>> ---------<br>
>> >>> >> >>>> 6000000<br>
>> >>> >> >>>> (1 row)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> ^Cedb=#<br>
>> >>> >> >>>> edb=#<br>
>> >>> >> >>>><br>
>> >>> >> >>>> *4. Checking session in database, state is now idle*<br>
>> >>> >> >>>><br>
>> >>> >> >>>> Sat 01 Aug 2020 07:28:14 AM UTC<br>
>> (every<br>
>> >>> 1s)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> pid | query | usename<br>
>> |<br>
>> >>> >> >>>> client_addr | count | state<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >><br>
>> >>><br>
>> ------+-----------------------------------------+--------------+-----------------+-------+-------<br>
>> >>> >> >>>> 3420 | select count(*) from pgbench_accounts ; | enterprisedb<br>
>> |<br>
>> >>> >> >>>> 128.199.224.132 | 1 | idle<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> *5. Checking session in database after 2 minutes, I can still<br>
>> see<br>
>> >>> the<br>
>> >>> >> >>>> database session idle*<br>
>> >>> >> >>>><br>
>> >>> >> >>>> Sat 01 Aug 2020 07:30:02 AM UTC<br>
>> (every<br>
>> >>> 1s)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> pid | query | usename<br>
>> |<br>
>> >>> >> >>>> client_addr | count | state<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >><br>
>> >>><br>
>> ------+-----------------------------------------+--------------+-----------------+-------+-------<br>
>> >>> >> >>>> 3420 | select count(*) from pgbench_accounts ; | enterprisedb<br>
>> |<br>
>> >>> >> >>>> 128.199.224.132 | 1 | idle<br>
>> >>> >> >>>><br>
>> >>> >> >>>> *6. Checking connection on pgpool server. connection is still<br>
>> open<br>
>> >>> >> from<br>
>> >>> >> >>>> pgpool to database*<br>
>> >>> >> >>>><br>
>> >>> >> >>>> ps -ef|grep edb<br>
>> >>> >> >>>> enterpr+ 24170 24162 0 06:51 ? 00:00:00 pgpool:<br>
>> >>> enterprisedb<br>
>> >>> >> edb<br>
>> >>> >> >>>> 128.199.222.92(34402) idle<br>
>> >>> >> >>>><br>
>> >>> >> >>>> *7. After being idle for more than 60 seconds, connections are<br>
>> >>> still<br>
>> >>> >> open<br>
>> >>> >> >>>> from pgpool and on database.Connection is removed from pgpool<br>
>> >>> server<br>
>> >>> >> after<br>
>> >>> >> >>>> I quit from the psql terminal but still present in the<br>
>> database as<br>
>> >>> >> show<br>
>> >>> >> >>>> below:*<br>
>> >>> >> >>>> Sat 01 Aug 2020 07:34:26 AM UTC (every 1s)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> pid | query | usename | client_addr | count |<br>
>> >>> state<br>
>> >>> >> >>>><br>
>> >>> ------+--------------+--------------+-----------------+-------+-------<br>
>> >>> >> >>>> 3420 | DISCARD ALL | enterprisedb | 128.199.224.132 | 1 |<br>
>> >>> idle<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> *Scenario2:*<br>
>> >>> >> >>>><br>
>> >>> >> >>>> max_pool=1<br>
>> >>> >> >>>> num_init_children=100<br>
>> >>> >> >>>> serialize_accept=on<br>
>> >>> >> >>>> child_max_connections=0<br>
>> >>> >> >>>> child_life_time=0<br>
>> >>> >> >>>> connection_life_time=0<br>
>> >>> >> >>>> client_idle_limit=60<br>
>> >>> >> >>>><br>
>> >>> >> >>>> *1. Connected to Pgpool and ran a query with \watch 1:*<br>
>> >>> >> >>>> edb=# \! date<br>
>> >>> >> >>>> Sat Aug 1 07:38:45 UTC 2020<br>
>> >>> >> >>>> select count(*) from pgbench_accounts ;<br>
>> >>> >> >>>> \watch 1<br>
>> >>> >> >>>> edb=# select count(*) from pgbench_accounts ;<br>
>> >>> >> >>>> count<br>
>> >>> >> >>>> ---------<br>
>> >>> >> >>>> 6000000<br>
>> >>> >> >>>> (1 row)<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> *2. Checking session in database, one session is active from<br>
>> >>> pgpool*<br>
>> >>> >> >>>><br>
>> >>> >> >>>> Sat 01 Aug 2020 07:39:55 AM UTC<br>
>> >>> (every 1s)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> pid | query | usename<br>
>> |<br>
>> >>> >> >>>> client_addr | count | state<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >><br>
>> >>><br>
>> -------+-----------------------------------------+--------------+-----------------+-------+--------<br>
>> >>> >> >>>> 13427 | select count(*) from pgbench_accounts ; |<br>
>> enterprisedb |<br>
>> >>> >> >>>> 128.199.224.132 | 1 | active<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> *3. Stopped the query after sometime using Ctrl-C but session<br>
>> is<br>
>> >>> still<br>
>> >>> >> >>>> open*<br>
>> >>> >> >>>> Sat 01 Aug 2020 07:41:39 AM UTC (every 1s)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> count<br>
>> >>> >> >>>> ---------<br>
>> >>> >> >>>> 6000000<br>
>> >>> >> >>>> ^Cedb=#<br>
>> >>> >> >>>> edb=#<br>
>> >>> >> >>>><br>
>> >>> >> >>>> *4. Checking session in database, state is now idle*<br>
>> >>> >> >>>><br>
>> >>> >> >>>> Sat 01 Aug 2020 07:42:12 AM UTC<br>
>> >>> (every 1s)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> pid | query | usename<br>
>> |<br>
>> >>> >> >>>> client_addr | count | state<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >><br>
>> >>><br>
>> -------+-----------------------------------------+--------------+-----------------+-------+-------<br>
>> >>> >> >>>> 13427 | select count(*) from pgbench_accounts ; |<br>
>> enterprisedb |<br>
>> >>> >> >>>> 128.199.224.132 | 1 | idle<br>
>> >>> >> >>>> (1 row)<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> *5. Checking session in database after 2 minutes, there is no<br>
>> >>> session<br>
>> >>> >> in<br>
>> >>> >> >>>> the database.*<br>
>> >>> >> >>>><br>
>> >>> >> >>>> Sat 01 Aug 2020 07:42:42 AM UTC (every 1s)<br>
>> >>> >> >>>><br>
>> >>> >> >>>> pid | query | usename | client_addr | count | state<br>
>> >>> >> >>>> -----+-------+---------+-------------+-------+-------<br>
>> >>> >> >>>> (0 rows)<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> *6. Checking connection on pgpool server. No connection open in<br>
>> >>> >> pgpool to<br>
>> >>> >> >>>> database*<br>
>> >>> >> >>>> ps -ef|grep edb<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> *Observations:*<br>
>> >>> >> >>>><br>
>> >>> >> >>>> With client_idle_limit of 60 seconds, all connections are<br>
>> closed<br>
>> >>> after<br>
>> >>> >> >>>> being idle for more than 1 minute. I can see psql session in<br>
>> >>> database<br>
>> >>> >> is<br>
>> >>> >> >>>> still present as shown below, because<br>
>> >>> >> >>>> I did not quit from psql terminal yet:<br>
>> >>> >> >>>><br>
>> >>> >> >>>> [root@master ~]# ps -ef |grep 128.199.224.132<br>
>> >>> >> >>>> enterpr+ 13193 28563 0 07:38 pts/0 00:00:00 /bin/bash<br>
>> >>> /bin/psql -p<br>
>> >>> >> >>>> 9999 -h 128.199.224.132<br>
>> >>> >> >>>> enterpr+ 13198 13193 0 07:38 pts/0 00:00:00 /bin/psql.bin<br>
>> -p<br>
>> >>> 9999<br>
>> >>> >> -h<br>
>> >>> >> >>>> 128.199.224.132<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> From scenario 2( client_idle_limit = 60), we can say that when<br>
>> >>> >> >>>> client_idle_limit is triggered client is disconnected, no<br>
>> database<br>
>> >>> >> >>>> connection is in use but the session still remains on<br>
>> server.If i<br>
>> >>> >> start<br>
>> >>> >> >>>> running query<br>
>> >>> >> >>>> on same psql session, it will first reset connection and then<br>
>> run<br>
>> >>> the<br>
>> >>> >> >>>> query, this will again create a new connection to the database.<br>
>> >>> >> >>>><br>
>> >>> >> >>>> From scenario 1(connection_life_time = 60), there is no real<br>
>> >>> benefit I<br>
>> >>> >> >>>> see. I assumed the connections(DISCARD ALL) present in database<br>
>> >>> will<br>
>> >>> >> be<br>
>> >>> >> >>>> reused but each time I connected to the database, it created a<br>
>> new<br>
>> >>> >> >>>> connection as seen below:<br>
>> >>> >> >>>><br>
>> >>> >> >>>> pid | query | usename | client_addr | count<br>
>> |<br>
>> >>> state<br>
>> >>> >> >>>><br>
>> >>> >><br>
>> -------+--------------+--------------+-----------------+-------+-------<br>
>> >>> >> >>>> 12895 | | enterprisedb | 128.199.224.132 | 1<br>
>> |<br>
>> >>> idle<br>
>> >>> >> >>>> 3420 | DISCARD ALL | enterprisedb | 128.199.224.132 | 1<br>
>> |<br>
>> >>> idle<br>
>> >>> >> >>>> 12531 | DISCARD ALL | enterprisedb | 128.199.224.132 | 1<br>
>> |<br>
>> >>> idle<br>
>> >>> >> >>>> 12636 | DISCARD ALL | enterprisedb | 128.199.224.132 | 1<br>
>> |<br>
>> >>> idle<br>
>> >>> >> >>>> 12698 | DISCARD ALL | enterprisedb | 128.199.224.132 | 1<br>
>> |<br>
>> >>> idle<br>
>> >>> >> >>>> 12751 | DISCARD ALL | enterprisedb | 128.199.224.132 | 1<br>
>> |<br>
>> >>> idle<br>
>> >>> >> >>>> 12773 | DISCARD ALL | enterprisedb | 128.199.224.132 | 1<br>
>> |<br>
>> >>> idle<br>
>> >>> >> >>>> 12862 | DISCARD ALL | enterprisedb | 128.199.224.132 | 1<br>
>> |<br>
>> >>> idle<br>
>> >>> >> >>>> 12878 | DISCARD ALL | enterprisedb | 128.199.224.132 | 1<br>
>> |<br>
>> >>> idle<br>
>> >>> >> >>>> (9 rows)<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> Thanks and Regards,<br>
>> >>> >> >>>> Nikhil<br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>><br>
>> >>> >> >>>> On Sat, Aug 1, 2020 at 6:45 PM Tatsuo Ishii <<br>
>> <a href="mailto:ishii@sraoss.co.jp" target="_blank" rel="noreferrer">ishii@sraoss.co.jp</a>><br>
>> >>> >> wrote:<br>
>> >>> >> >>>><br>
>> >>> >> >>>>> > Hi,<br>
>> >>> >> >>>>> ><br>
>> >>> >> >>>>> > Yes, we can see the pid<br>
>> >>> >> >>>>> ><br>
>> >>> >> >>>>> > show pool_pools;<br>
>> >>> >> >>>>> > pool_pid | start_time | pool_id | backend_id |<br>
>> >>> database |<br>
>> >>> >> >>>>> > username | create_time | majorversion |<br>
>> minorversion<br>
>> >>> |<br>
>> >>> >> >>>>> > pool_counter | pool_backendpid | pool_connected<br>
>> >>> >> >>>>> ><br>
>> >>> >> >>>>> > 18190 | 2020-08-01 06:14:41 | 0 | 1 | edb<br>
>> >>> |<br>
>> >>> >> >>>>> > enterprisedb | 2020-08-01 06:19:52 | 3 | 0<br>
>> >>> |<br>
>> >>> >> 1<br>
>> >>> >> >>>>> > | *29321* | 0<br>
>> >>> >> >>>>> > 18193 | 2020-08-01 06:14:41 | 0 | 1 | edb<br>
>> >>> |<br>
>> >>> >> >>>>> > enterprisedb | 2020-08-01 06:21:26 | 3 | 0<br>
>> >>> |<br>
>> >>> >> 1<br>
>> >>> >> >>>>> > | *29619 *| 0<br>
>> >>> >> >>>>> ><br>
>> >>> >> >>>>> ><br>
>> >>> >> >>>>> > select pid,query,usename,state from pg_stat_activity where<br>
>> >>> >> >>>>> > client_addr='128.199.224.132' group by usename,query,pid;<br>
>> >>> >> >>>>> > pid | query | usename | state<br>
>> >>> >> >>>>> > -------+--------------+--------------+-------<br>
>> >>> >> >>>>> > *29321 *| DISCARD ALL | enterprisedb | idle<br>
>> >>> >> >>>>> > *29619* | DISCARD ALL | enterprisedb | idle<br>
>> >>> >> >>>>><br>
>> >>> >> >>>>> Assuming you executed "show pool_pools" long after 2020-08-01<br>
>> >>> >> >>>>> 06:21:26, that is very strange because connection_life_time<br>
>> >>> should<br>
>> >>> >> >>>>> have been already expired. I wonder if pgpool tried to<br>
>> >>> disconnect the<br>
>> >>> >> >>>>> connection but failed. To check what actually happend, can you<br>
>> >>> check<br>
>> >>> >> >>>>> ps status of pgpool process 18190 and 18193?<br>
>> >>> >> >>>>><br>
>> >>> >> >>>>> Also it would be nice you can examine the socket status of<br>
>> >>> PostgreSQL<br>
>> >>> >> >>>>> backend 29321 and 29619, and pgpool socket status of process<br>
>> >>> 18190<br>
>> >>> >> and<br>
>> >>> >> >>>>> 18193?<br>
>> >>> >> >>>>><br>
>> >>> >> >>>>> Best regards,<br>
>> >>> >> >>>>> --<br>
>> >>> >> >>>>> Tatsuo Ishii<br>
>> >>> >> >>>>> SRA OSS, Inc. Japan<br>
>> >>> >> >>>>> English: <a href="http://www.sraoss.co.jp/index_en.php" rel="noreferrer noreferrer" target="_blank">http://www.sraoss.co.jp/index_en.php</a><br>
>> >>> >> >>>>> Japanese:<a href="http://www.sraoss.co.jp" rel="noreferrer noreferrer" target="_blank">http://www.sraoss.co.jp</a><br>
>> >>> >> >>>>><br>
>> >>> >> >>>><br>
>> >>> >> > _______________________________________________<br>
>> >>> >> > pgpool-general mailing list<br>
>> >>> >> > <a href="mailto:pgpool-general@pgpool.net" target="_blank" rel="noreferrer">pgpool-general@pgpool.net</a><br>
>> >>> >> > <a href="http://www.pgpool.net/mailman/listinfo/pgpool-general" rel="noreferrer noreferrer" target="_blank">http://www.pgpool.net/mailman/listinfo/pgpool-general</a><br>
>> >>> >><br>
>> >>><br>
>> >><br>
>><br>
</blockquote></div>