[pgpool-general: 7223] Re: Idle connection in database

Nikhil Shetty nikhil.dba04 at gmail.com
Sun Aug 30 17:08:22 JST 2020


Hi Tatsuo,

I am using Pgpool v4.1.1.

I have seen similiar behaviour in v4.0.9 as well.

Thanks and Regards,
Nikhil

On Sun, Aug 30, 2020, 13:11 Tatsuo Ishii <ishii at sraoss.co.jp> wrote:

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