[pgpool-general: 9320] pgpool-II INSERTS are not persistent (most likely with prepared statements)

[Gerhard Wiesinger]

Hello,

I made an upgrade of the following PostgreSQL and pgpool-II components:
- PostgreSQL: 9.6.10 to 17.2
- pgpool-II: pgpool-II-3.7.5 to pgpool-II-4.5.5

I only want to use pgpool-II for connection pooling (worked flawless 
with all of the old versions).

Architecture looks like:
Clients <-> pgpool-II <-> PostgreSQL-Server (single instance)

After the upgrade, I'm having a problem that some INSERTS (looks like 
with Prepared Statements only) don't work and are executed correctly on 
the PostgreSQL Server (e.g. sequences are counted up). SELECTs done 
immediatly (e.g. web page updates) get the new data BUT FOR ONLY SOME 
seconds. Then the data is removed somehow (connection loss/different 
connection?).

SELECTs in general work well.

When I'm removing pgpool-II from the chain everything works well!

Status of different clients for different scenarios of INSERTs:
- 2x PHP apps with prepared statements: NOT OK
- Perl Code without prepared statements: OK
- PGAdmin4 manual execution (as reference): OK

Non default pgpool-II config: see below:

Any ideas what's happening?
Does the configuration for connection pooling look feasible?
Any ideas why this happens only with prepared statements?

OS: Fedora 41
all other versions from PGDG.
detailed pgpool version: pgpool-II-4.5.5-1PGDG.f41.x86_64
detailed PostgreSQL version: postgresql17-server-17.2-1PGDG.f41.x86_64

If you need further information let me know.

Thnx.

Ciao,
Gerhard

Non standard config values:
backend_clustering_mode = 'raw'
listen_addresses = '*'
unix_socket_directories = '/run/pgpool-II'
pcp_listen_addresses = '*'
backend_hostname0 = 'localhost'
backend_port0 = 5432
backend_weight0 = 1
backend_data_directory0 = '/var/lib/pgsql/17/data'
backend_flag0 = 'ALLOW_TO_FAILOVER'
enable_pool_hba = off
num_init_children = 32
child_life_time = 10
connection_life_time = 2
pid_file_name = '/run/pgpool-II/pgpool.pid'
hostname0 = ''