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Pgbouncer and Node JS application Query read timeout error

Jump to comment-1
KK CHN<kkchn.in@gmail.com>
Apr 8, 2026, 5:14 AM UTC
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]
rptdb = host=dbmain.mydomain.com port=5444 dbname=rptdb
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
maxpreparedstatements = 120
serverresetquery = DISCARD ALL
serverresetquery_always = 1
ignorestartupparameters = extrafloatdigits, options, statement_timeout,
idleintransactionsessiontimeout
maxclientconn = 5000
defaultpoolsize = 50
minpoolsize = 30
reservepoolsize = 10
reservepooltimeout = 5
maxdbconnections = 130
maxuserconnections = 180
server_lifetime = 3600
serveridletimeout = 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 { DBHOST, DBNAMEMGT, DBNAMETSP, DBNAMERDB, DBUSER,
DBPASSWORD, DBPORT } = 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
View in PostgreSQL Archives →
- Jump to comment-1
  Laurenz Albe<laurenz.albe@cybertec.at>
  Apr 8, 2026, 6:28 AM UTC
  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
  defaultpoolsize = 50
  minpoolsize = 30
  reservepoolsize = 10
  reservepooltimeout = 5
  maxdbconnections = 130
  maxuserconnections = 180
  server_lifetime = 3600
  serveridletimeout = 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
  View in PostgreSQL Archives →
  Jump to comment-1
  KK CHN<kkchn.in@gmail.com>
  Apr 10, 2026, 7:00 AM UTC
  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
  defaultpoolsize = 50
  minpoolsize = 30
  reservepoolsize = 10
  reservepooltimeout = 5
  maxdbconnections = 130
  maxuserconnections = 180
  server_lifetime = 3600
  serveridletimeout = 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 defaultpoolsize = 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
  View in PostgreSQL Archives →
  Jump to comment-1
  Laurenz Albe<laurenz.albe@cybertec.at>
  Apr 10, 2026, 7:34 AM UTC
  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
  defaultpoolsize = 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
  View in PostgreSQL Archives →