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IDProjectCategoryView StatusLast Update
0000746Pgpool-IIGeneralpublic2022-06-28 22:44
Reportergarg1982@gmail.com Assigned Tokawamoto  
PrioritynormalSeveritymajorReproducibilityrandom
Status closedResolutionopen 
Product Version4.1.2 
Summary0000746: Getting below error in pgpool log on salve server. Need your help to find the reason of it.
DescriptionBelow are error messages from pgpool log
 
LOG: trying connecting to PostgreSQL server on "10.144.1.29:5432" by INET socket
DETAIL: timed out. retrying...
 LOG: trying connecting to PostgreSQL server on "10.144.1.29:5432" by INET socket
 DETAIL: timed out. retrying...
LOG: trying connecting to Postgres

2022-03-14 11:26:06: pid 48605: LOG: fork a new child process with pid: 183760
2022-03-14 11:26:06: pid 48605: LOG: child process with pid: 110355 exits with status 256
2022-03-14 11:26:06: pid 48605: LOG: fork a new child process with pid: 183761
2022-03-14 11:26:06: pid 48605: LOG: child process with pid: 81995 exits with status 256
2022-03-14 11:26:06: pid 48605: LOG: fork a new child process with pid: 183762
2022-03-14 11:26:06: pid 48605: LOG: child process with pid: 84194 exits with status 256
2022-03-14 11:26:06: pid 48605: LOG: fork a new child process with pid: 183763
2022-03-14 11:26:06: pid 48605: LOG: child process with pid: 176810 exits with status 256
2022-03-14 11:26:06: pid 48605: LOG: fork a new child process with pid: 183764
2022-03-14 11:26:06: pid 48605: LOG: child process with pid: 108921 exits with status 256
2022-03-14 11:26:06: pid 48605: LOG: fork a new child process with pid: 183765


2022-03-14 11:26:57: pid 184451: HINT: repair the backend nodes and restart pgpool
2022-03-14 11:26:57: pid 184452: FATAL: pgpool is not accepting any new connections
2022-03-14 11:26:57: pid 184452: DETAIL: all backend nodes are down, pgpool requires at least one valid node
2022-03-14 11:26:57: pid 184452: HINT: repair the backend nodes and restart pgpool
2022-03-14 11:26:57: pid 184453: FATAL: pgpool is not accepting any new connections
2022-03-14 11:26:57: pid 184453: DETAIL: all backend nodes are down, pgpool requires at least one valid node
2022-03-14 11:26:57: pid 184453: HINT: repair the backend nodes and restart pgpool
2022-03-14 11:26:57: pid 184454: FATAL: pgpool is not accepting any new connections
2022-03-14 11:26:57: pid 184454: DETAIL: all backend nodes are down, pgpool requires at least one valid node

Now I am getting error while connecting to server

-bash-4.2$ psql -p 9999
psql: error: could not connect to server: FATAL: Sorry, too many clients already

Steps To ReproduceThis issue happened twice in last week
TagsNo tags attached.

Activities

kawamoto

2022-03-17 17:44

developer   ~0003999

Hi garg1982.

---
2022-03-14 11:26:57: pid 184454: FATAL: pgpool is not accepting any new connections
2022-03-14 11:26:57: pid 184454: DETAIL: all backend nodes are down, pgpool requires at least one valid node
---
This messages say that the status of all backend PostgreSQL node were DOWN.

Did you check if PostgreSQL was running and the network was healthy
when the error occurred?

What situation does this error occur?
When you start Pgpool up?
Does it occur suddenly during operation?

garg1982@gmail.com

2022-03-17 20:49

reporter   ~0004000

Hi Kawamoto,

Postgres services are running fine on both nodes (master and slave).

We have master/slave setup and each node have pgpool too. Application using jdbc driver and both nodes IP mentioned in connection string to connect to the database.

This error came for few minutes only in log " trying connecting to PostgreSQL server on "10.144.1.29:5432" by INET socket". Thereafter we aren't able to connect using pgpool which is running on slave node, even postgres services are running fine. However we can can connect directly without pgpool and other pgpool which is running on master node.

We are taking restart pgpool on slave node tonight to fix it but same issue has occurred twice in a week.

I just want to check why pgpool automatically recognized the health of backend node because it is running fine or is it usual behavior of pgpool means whenever there are session termination, pgpool need to restart

Thanks
Gaurav

kawamoto

2022-03-18 14:08

developer   ~0004001

Hi Gaurav,

Pgpool has two backends and fail the healthcheck about one node "10.144.1.29".
Then, pgpool reports that has no active backend nodes.
This is strange behavior. Pgpool should have another node that has not failed healthcheck.

To confirm the status of the backends that pgpool currently knows, please throw "show pool_nodes" command
to both pgpool and upload the outputs.
$psql -p 9999 -x -c "show pool_nodes"

> I just want to check why pgpool automatically recognized the health of backend node because it is running
> fine or is it usual behavior of pgpool means whenever there are session termination, pgpool need to restart
If you set 'auto_failback = on' in pgpool.conf, pgpool can automatically detect the failed backend if it becomes
healthy, and re-attach it to cluster.
https://www.pgpool.net/docs/41/en/html/runtime-config-failover.html#GUC-AUTO-FAILBACK

garg1982@gmail.com

2022-03-21 13:38

reporter   ~0004003

Hi Kawamoto,

We have restarted the PGPOOL so issue has been fixed now. I will come back to you if similar issue encounter again in future. Thanks for your time !!

Just want to check one thing, do we have any benefit if we separate PGPOOL from db nodes. Please note we are using it only for Load balancing and connection pooling.

Regards
Gaurav

kawamoto

2022-03-25 13:29

developer   ~0004009

Sorry for the late reply.

>Just want to check one thing, do we have any benefit if we separate PGPOOL from db nodes. Please note we are using it only for Load balancing and connection pooling.

Consider when the server running pgpool goes down. If pgpool and postgresql run on
the same server, database availability will be lost because the postgresql goes down
too, but if they are separated, availability and load balancing performance will be
maintained because the two postgresql are still running.

garg1982@gmail.com

2022-05-10 14:42

reporter   ~0004030

Thank you for the update and support !!

administrator

2022-06-28 11:57

administrator   ~0004079

May I close this issue?

garg1982@gmail.com

2022-06-28 22:40

reporter   ~0004085

Yes, please. Thanks

administrator

2022-06-28 22:44

administrator   ~0004086

Close issue.

Issue History

Date Modified Username Field Change
2022-03-17 15:57 garg1982@gmail.com New Issue
2022-03-17 16:33 kawamoto Assigned To => kawamoto
2022-03-17 16:33 kawamoto Status new => assigned
2022-03-17 17:44 kawamoto Note Added: 0003999
2022-03-17 20:49 garg1982@gmail.com Note Added: 0004000
2022-03-18 14:08 kawamoto Note Added: 0004001
2022-03-21 13:38 garg1982@gmail.com Note Added: 0004003
2022-03-25 13:29 kawamoto Note Added: 0004009
2022-05-10 14:42 garg1982@gmail.com Note Added: 0004030
2022-06-28 11:57 administrator Note Added: 0004079
2022-06-28 22:40 garg1982@gmail.com Note Added: 0004085
2022-06-28 22:44 administrator Status assigned => closed
2022-06-28 22:44 administrator Note Added: 0004086