Thread

1. Pgbouncer and Node JS application Query read timeout error

   KK CHN <kkchn.in@gmail.com> — 2026-04-08T05:21:32Z

   List,
   
   I am using pgbouncer(PgBouncer 1.23.1 RHEL 9.4) along with  Postgres16(RHEL
   9.4)  for connection pooling.
   
   
    Running a nodejs application which is throwing some errors  related to
   query timeout which the development team suspect after pgbouncer deployment
   this behaviour appears, but not sure
   
   
   The error which is thrown from  the nodejs logs as follows..
   
   [image: image.png]
   Is this due to   pgbouncer config issues or   nodejs  pool config issues ?
      ( Also the nodejs application  restarts frequently after running for
   quiet few hours  as per the dev team reported, may be code level / mem
   leak/GC    issues but need to roll out this don't have any connection with
   pgbouncer deployment.
   
   
   for  reference here the pgbouncer  config params and  node js  params at
   present.           Any hints much helpful to rule out this is pgbouncer
   config issues ...
   
   
   *pgbouncer.ini*
   
   [databases]
   
   rpt_db = host=dbmain.mydomain.com port=5444 dbname=rpt_db
   postgres = host=dbmain.mydomain.com=5444 dbname=postgres
   keycloak = host=dbmain.mydomain.com=5444 dbname=keycloak
   [users]
   [pgbouncer]
   logfile = /var/log/pgbouncer/pgbouncer.log
   pidfile = /var/run/pgbouncer/pgbouncer.pid
   listen_addr = *
   listen_port = 5444
   auth_type = md5
   auth_file = /usr/local/etc/pgbouncer.users
   admin_users = myuser
   stats_users = myuser
   pool_mode = transaction
   max_prepared_statements = 120
   server_reset_query = DISCARD ALL
   server_reset_query_always = 1
   ignore_startup_parameters = extra_float_digits, options, statement_timeout,
   idle_in_transaction_session_timeout
   
   max_client_conn = 5000
   default_pool_size = 50
   min_pool_size = 30
   reserve_pool_size = 10
   reserve_pool_timeout = 5
   max_db_connections = 130
   max_user_connections = 180
   server_lifetime = 3600
   server_idle_timeout = 600
   [root@pgbouncer ~]#
   
   
   *NodeJS application  pg-pool-config.js     // *
   
   import pkg from 'pg';
   import { config } from 'dotenv';
   import dblogger from '../helpers/dblogger.js';
   const { Pool } = pkg;
   config();
   
   const { DB_HOST, DB_NAME_MGT, DB_NAME_TSP, DB_NAME_RDB, DB_USER,
   DB_PASSWORD, DB_PORT } = process.env;
   
   const poolOptions = {
       max: 10,
       min: 2,
       idleTimeoutMillis: 600000,   //Idle for 5Min
       connectionTimeoutMillis: 10000,  //Reconnect 10sec
       //statement_timeout: 60000,    //Query executiion 1 min
       acquire: 20000,
       maxUses: 1000 //reconnect after 1000 queries
   };
   ..................
   ............
   
   
   
   
   *TOP OUTPUT ON Pgbouncer VM *
   
   last pid: 17171;  load averages:  0.45,  0.39,  0.40             up
   7+07:19:36  10:34:48
   23 processes:  1 running, 20 sleeping, 2 stopped
   CPU:  0.5% user,  0.0% nice,  3.6% system,  0.0% interrupt, 95.9% idle
   Mem: 13M Active, 1352M Inact, 1415M Wired, 1024M Buf, 13G Free
   Swap: 7068M Total, 7068M Free
   
     PID USERNAME    THR PRI NICE   SIZE    RES STATE    C   TIME    WCPU
   COMMAND
     828 pgbouncer     1  48    0    25M    12M kqread   0  43.6H  20.45%
   pgbouncer
     217 root          3  20    0    53M    28M select   6   6:30   0.05%
   vmtoolsd
   
   
   
   
   *TOP OUTPUT ON    NODE JS  VM*
   
   top - 10:35:52 up 195 days,  5:37,  5 users,  load average: 0.89, 0.86, 0.91
   Tasks: 612 total,   8 running, 604 sleeping,   0 stopped,   0 zombie
   %Cpu(s):  2.9 us,  0.3 sy,  0.0 ni, 96.3 id,  0.0 wa,  0.1 hi,  0.3 si,
    0.0 st
   MiB Mem :  63785.5 total,  50434.0 free,   8909.5 used,   5429.2 buff/cache
   MiB Swap:   4044.0 total,   4032.4 free,     11.6 used.  54875.9 avail Mem
   
       PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+
   COMMAND
      4120 root      20   0 1140028 621676  36864 S  18.6   1.0  51895:18 node
   1914526 root      20   0   21.0g 251816  49152 S   9.3   0.4   4:16.81 node
   /v
   
   
   *TOP OUTPUT ON DB SERVER VM*
   
   *   (  *[root@db1 ~]# grep -c ^processor /proc/cpuinfo
   16
   [root@db1 ~]#   )
   
   TOP
   top - 10:37:22 up 407 days, 15:24,  1 user,  load average: 9.75, 10.65, 9.09
   Tasks: 500 total,   2 running, 498 sleeping,   0 stopped,   0 zombie
   %Cpu(s): 16.8 us,  8.8 sy,  0.0 ni, 49.7 id, 23.2 wa,  0.4 hi,  1.1 si,
    0.0 st
   MiB Mem :  31837.6 total,    351.4 free,  10369.1 used,  30018.5 buff/cache
   MiB Swap:   8060.0 total,   6908.2 free,   1151.8 used.  21468.5 avail Mem
   
       PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+
   COMMAND
   1842514 postgres+  20   0 8961888   2.4g   2.4g R  26.8   7.7   0:00.86
   postgres
   1827606 postgres+  20   0   21208   7808   7808 S  26.1   0.0   5:17.38
   pgbackrest
   1827611 postgres+  20   0   30596  18220   8064 D  25.1   0.1   3:54.74
   pgbackrest
   
   
   
   
   Any more inputs required let me know..
   
   
   Thank you,
   
   Krishane
   

2. Re: Pgbouncer and Node JS application Query read timeout error

   Laurenz Albe <laurenz.albe@cybertec.at> — 2026-04-08T06:27:59Z

   On Wed, 2026-04-08 at 10:51 +0530, KK CHN wrote:
   > List, I am using pgbouncer(PgBouncer 1.23.1 RHEL 9.4) along with  Postgres16(RHEL 9.4)
   > for connection pooling.   
   > 
   > Running a nodejs application which is throwing some errors  related to query timeout
   > which the development team suspect after pgbouncer deployment this behaviour appears,
   > but not sure 
   > 
   > The error which is thrown from  the nodejs logs as follows.. 
   > 
   > [image showing an error "Query read timeout"]
   >
   > Is this due to   pgbouncer config issues or   nodejs  pool config issues ?
   > 
   > for  reference here the pgbouncer  config params and  node js  params at present.
   > 
   > pgbouncer.ini
   > 
   > [...]
   > [pgbouncer]
   > pool_mode = transaction
   > default_pool_size = 50
   > min_pool_size = 30
   > reserve_pool_size = 10
   > reserve_pool_timeout = 5
   > max_db_connections = 130
   > max_user_connections = 180
   > server_lifetime = 3600
   > server_idle_timeout = 600
   > [...]
   
   
   The only way I can imagine that pgBouncer is leading to timeouts on the client side
   is if client sessions are waiting, because all connections are in use.
   
   You can run SHOW POOLS in the pgBouncer console to see if there are any "cl_waiting".
   If that is the case, you should configure the Node.js pools smaller, so that no
   connection has to wait.
   
   Yours,
   Laurenz Albe
   
   
   
   

3. Re: Pgbouncer and Node JS application Query read timeout error

   KK CHN <kkchn.in@gmail.com> — 2026-04-10T07:07:22Z

   On Wed, Apr 8, 2026 at 11:58 AM Laurenz Albe <laurenz.albe@cybertec.at>
   wrote:
   
   > On Wed, 2026-04-08 at 10:51 +0530, KK CHN wrote:
   > > List, I am using pgbouncer(PgBouncer 1.23.1 RHEL 9.4) along with
   > Postgres16(RHEL 9.4)
   > > for connection pooling.
   > >
   > > Running a nodejs application which is throwing some errors  related to
   > query timeout
   > > which the development team suspect after pgbouncer deployment
   > this behaviour appears,
   > > but not sure
   > >
   > > The error which is thrown from  the nodejs logs as follows..
   > >
   > > [image showing an error "Query read timeout"]
   > >
   > > Is this due to   pgbouncer config issues or   nodejs  pool config issues
   > ?
   > >
   > > for  reference here the pgbouncer  config params and  node js  params at
   > present.
   > >
   > > pgbouncer.ini
   > >
   > > [...]
   > > [pgbouncer]
   > > pool_mode = transaction
   > > default_pool_size = 50
   > > min_pool_size = 30
   > > reserve_pool_size = 10
   > > reserve_pool_timeout = 5
   > > max_db_connections = 130
   > > max_user_connections = 180
   > > server_lifetime = 3600
   > > server_idle_timeout = 600
   > > [...]
   >
   >
   > The only way I can imagine that pgBouncer is leading to timeouts on the
   > client side
   > is if client sessions are waiting, because all connections are in use.
   >
   > You can run SHOW POOLS in the pgBouncer console to see if there are any
   > "cl_waiting".
   > If that is the case, you should configure the Node.js pools smaller, so
   > that no
   > connection has to wait.
   >
   
   Configuring Node.js  pools smaller ?  I couldn't get the  logic here  why
   advised to reduce the pool size ?
   
   Increasing pool size  more than 10 adversely affects the connection
   establishment from Node.js  application ?          Since DB  is having
    Pgbouncer infront and   default_pool_size = 50 there ,  don't we have the
   freedom to increase node.js application pool size and it will help the
   query timeout ?   or any hidden facts involved could you elaborate ..
   
   
   Thank you,
   Krishane
   
   
   
   >
   > Yours,
   > Laurenz Albe
   >
   

4. Re: Pgbouncer and Node JS application Query read timeout error

   Laurenz Albe <laurenz.albe@cybertec.at> — 2026-04-10T07:29:01Z

   On Fri, 2026-04-10 at 12:37 +0530, KK CHN wrote:
   > > The only way I can imagine that pgBouncer is leading to timeouts on the client side
   > > is if client sessions are waiting, because all connections are in use.
   > > 
   > > You can run SHOW POOLS in the pgBouncer console to see if there are any "cl_waiting".
   > > If that is the case, you should configure the Node.js pools smaller, so that no
   > > connection has to wait.
   > 
   > Configuring Node.js  pools smaller ?  I couldn't get the  logic here  why advised to reduce the pool size ? 
   >  
   > Increasing pool size  more than 10 adversely affects the connection  establishment from
   > Node.js  application ?          Since DB  is having   Pgbouncer infront and
   > default_pool_size = 50 there ,  don't we have the freedom to increase node.js application
   > pool size and it will help the query timeout ?   or any hidden facts involved could you elaborate ..
   
   There are no hidden facts.
   
   You asked if pgBouncer could lead to query timeouts.  I answered that the only way a query
   could take significantly longer with pgBouncer is if the client has to wait for a pooled
   connections, that is, if the connection pool in pgBouncer is smaller than the number of
   clients that want to run a transaction concurrently.
   
   BEFORE you take any action, you should figure out if that is the case by looking
   at SHOW POOLS.  Since you didn't report any findings, I assume that you launched your
   volley of questions before doing the required investigation.  Bad idea.
   
   IF (and only if) there are indeed client sessions waiting for a pooled connection,
   you could react in two different ways:
   
   - increase the pgBouncer pool size
   - reduce the application server pool size
   
   Obvious, isn't it?
   
   Increasing the pgBouncer pool size is a good idea only if your database machine can
   stomach the additional load.  If not, reducing the application server pool size is
   the correct measure.  If the application load is too much for the database, somebody
   has to suffer.  If you choose to overload the database, everybody will be unhappy.
   If you throttle the load in the connection pool, only some client will be unhappy
   (those that have to wait and get a timeout).
   
   You will have to diagnose what the exact problem is.
   
   Yours,
   Laurenz Albe