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IDProjectCategoryView StatusLast Update
0000480Pgpool-II[All Projects] Generalpublic2019-08-26 10:04
ReporterbenAssigned Topengbo 
PrioritynormalSeverityminorReproducibilityhave not tried
Status feedbackResolutionopen 
PlatformlinuxOSUbuntuOS Version16.04.5 LTS
Product Version3.4.3 
Target VersionFixed in Version 
Summary0000480: FATAL: unable to read data from DB node 0 Detail: EOF encountered with backend.
DescriptionHi all,

I have two servers PostgresSQL Master/Slave - Slot Replication
I also have a scenario PostgreSQL HA with pgpool-II

All Server [Virtual Maschine] are running on:
Ubuntu 16.04.5 LTS
postgresql-9-5-pgpool2 version 3.4.3-1
pgpool2 version 3.4.3-1
Tomcat7
psql (9.5.14)

Server PgpoolII : Tomcat7 + pgpool_master(primary)IP: x.x.x.x
Server PgpoolII : tomcat7 + pgpool_slave (standby)IP: x.x.x.x

Server Master : PGsql Backend (primary - node 0)IP: x.x.x.x
Server Slave : PGsql Backend (standby - node 1)IP: x.x.x.x


Use Case:
What happens if the Master Server [PGsql Backend - (node 0)] is completely turned off?

1. Standby Server is automatically converted to Master Server (using the failover_command of the pgpool process).

Before turning off the server:
root@pgps2:~# su - postgres
postgres@pgps2:~$ psql -h localhost -p 5433 -c "show pool_nodes" postgres
 node_id | hostname | port | status | lb_weight | role
---------+---------------+------+--------+-----------+---------
 0 | x.x.x.x | 5432 | 2 | 0.500000 | primary
 1 | x.x.x.x | 5432 | 2 | 0.500000 | standby
(2 rows)


After turning off the server:
root@pgps2:~# su - postgres
postgres@pgps2:~$ psql -h localhost -p 5433 -c "show pool_nodes" postgres
 node_id | hostname | port | status | lb_weight | role
---------+---------------+------+--------+-----------+---------
 0 | x.x.x.x | 5432 | 3 | 0.500000 | standby
 1 | x.x.x.x | 5432 | 2 | 0.500000 | primary
(2 rows)


2. The Web Application (from Tomcat7 - pgpool_master) no longer has any connection to the database.

From Firefox:

Internal Error
org.hibernate.exception.JDBCConnectionException: could not inspect JDBC autocommit mode
javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: could not inspect JDBC autocommit mode at


3. The following error is received:

Pgpool LOG:

org.postgresql.util.PSQLException: FATAL: unable to read data from DB node 0 Detail: EOF encountered with backend.


4. The two Tomcat7-Pgpool2-Server show, that there is no connection with the database.

postgres@pgps2:~$ psql -h x.x.x.x -p 5433 -c "show pool_nodes" postgres
psql: server closed the connection unexpectedly
    This probably means the server terminated abnormally
    before or while processing the request.
postgres@pgps2:~$



What can be done here so that pgpool does not cut the connection to the database, but pgpool2 and also tomcat7 (Web Application) recognize the connection to the database?


Best regards, a help in advance is appreciated.

Ben
TagsNo tags attached.

Activities

pengbo

2019-03-27 09:02

developer   ~0002465

Does it also occur in latest version of 3.4.x?

ben

2019-04-01 16:13

reporter   ~0002491

I have tested the version pgpool-3.6.1 and it has the same problem.

Log pgpool:
pid 6437: LOG: failed to connect to PostgreSQL server on "x.x.x.x:5432", getsockopt() detected error "connection refused"
pid 6437: ERROR: failed to make persistent db connection

Log tomcat7:
org.postgresql.util.PSQLException: This connection has been closed.

Here is a URL: http://www.sraoss.jp/pipermail/pgpool-general/2018-December/006382.html
Is this URL similar to this problem?
Is there any idea to solve this feature?

pengbo

2019-04-01 16:40

developer   ~0002492

If possible, could you try pgpool-II 3.6.16?

Could you provide the debug log of Pgpool-II or could you provide a test program to help us to reproduce this issue.

pengbo

2019-08-26 10:04

developer   ~0002799

No response more than one month.
May I close this issue?

Issue History

Date Modified Username Field Change
2019-03-26 17:37 ben New Issue
2019-03-27 09:02 pengbo Note Added: 0002465
2019-04-01 16:13 ben Note Added: 0002491
2019-04-01 16:33 administrator Assigned To => pengbo
2019-04-01 16:33 administrator Status new => assigned
2019-04-01 16:40 pengbo Note Added: 0002492
2019-04-07 23:05 pengbo Status assigned => feedback
2019-08-26 10:04 pengbo Note Added: 0002799