public inbox for [email protected]  
help / color / mirror / Atom feed
[email protected]
2+ messages / 2 participants
[nested] [flat]

* [email protected]
@ 2026-03-03 10:02 [email protected]
  2026-03-05 04:32 ` Re: [email protected] Tatsuo Ishii <[email protected]>
  0 siblings, 1 reply; 2+ messages in thread

From: [email protected] @ 2026-03-03 10:02 UTC (permalink / raw)
  To: [email protected]

Hello,
i  have a problem with error which occurs on my pgpool cluster. The log 
messages i collected for this error :

2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: ERROR:  unable 
to write data to frontend
2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: DETAIL: 
pool_flush failed
2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOCATION: 
pool_stream.c:539
2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOG:  frontend 
disconnection: session time: 0:00:32.989 user=network_app_prod_adm 
database=network_app_prod host=cdis000phaux173.cdis.cz port=63675
2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOCATION: 
child.c:2110
2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOG:  DB node 
id: 0 backend pid: 3935771 statement: DISCARD ALL
2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOCATION: 
pool_proto_modules.c:3802
2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOG:  DB node 
id: 2 backend pid: 199834 statement: DISCARD ALL
2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOCATION: 
pool_proto_modules.c:3802
2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: WARNING: 
packet kind of backend 2 ['Z'] does not match with main/majority nodes 
packet kind ['D']
2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: LOCATION: 
pool_process_query.c:3713
2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: FATAL:  failed 
to read kind from backend
2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: DETAIL:  kind 
mismatch among backends. Possible last query was: "DISCARD ALL" kind 
details are: 0[D] 2[Z]
2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: HINT:  check 
data consistency among db nodes
2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: LOCATION: 
pool_process_query.c:3810

The customer complaints that the statement he is trying to send to 
database (INSERT) is basicaly not entered into the database. This error 
happenes several times a day, 
My version of pgpool and database : 

postgres@postgre-cdis-clu-pha-db3:/var/lib/pgsql/data/log> pgpool -version
pgpool-II version 4.5.10 (hotooriboshi)

postgres@postgre-cdis-clu-pha-db3:/var/lib/pgsql/data/log> psql -version
psql (16.11)
Type "help" for help.

The configuration of cluster:

postgres@postgre-cdis-clu-pha-db3:/var/lib/pgsql/data/log> 
pcp_watchdog_info -h 10.31.8.28 -p 9898 -U pgpool
3 3 YES postgre-cdis-clu-pha-db3:9999 Linux postgre-cdis-clu-pha-db3 
postgre-cdis-clu-pha-db3

postgre-cdis-clu-pha-db3:9999 Linux postgre-cdis-clu-pha-db3 
postgre-cdis-clu-pha-db3 9999 9000 4 LEADER 0 MEMBER
postgre-cdis-clu-pha-db1:9999 Linux postgre-cdis-clu-pha-db1 
postgre-cdis-clu-pha-db1 9999 9000 7 STANDBY 0 MEMBER
postgre-cdis-clu-pha-db2:9999 Linux postgre-cdis-clu-pha-db2 
postgre-cdis-clu-pha-db2 9999 9000 7 STANDBY 0 MEMBER

postgres@postgre-cdis-clu-pha-db3:/var/lib/pgsql/data/log> psql -h 
10.31.8.28 -p 9999 -U pgpool postgres -c "show pool_nodes"
 node_id |         hostname         | port | status | pg_status | 
lb_weight |  role   | pg_role | select_cnt | load_balance_node | 
replication_delay | replication_state | replicati
on_sync_state | last_status_change
---------+--------------------------+------+--------+-----------+-----------+---------+---------+------------+-------------------+-------------------+-------------------+----------
--------------+---------------------
 0       | postgre-cdis-clu-pha-db1 | 5432 | up     | up        | 0.333333 
 | standby | standby | 14069796   | false             | 0 | streaming    | 
async
              | 2026-03-02 15:28:50
 1       | postgre-cdis-clu-pha-db2 | 5432 | up     | up        | 0.333333 
 | standby | standby | 13284878   | true              | 0 | streaming    | 
async
              | 2026-03-02 15:28:50
 2       | postgre-cdis-clu-pha-db3 | 5432 | up     | up        | 0.333333 
 | primary | primary | 15253310   | false             | 0 |    |
              | 2026-03-02 15:28:50
(3 rows)

There are no errors at database level in the database log.
Any advice how to solve this ?


Thanks and regards
Zdenek Koktan



Tento email je určen výlučně adresátovi, popřípadě adresátům, a jeho obsah 
je důvěrný. Pokud jste tuto zprávu obdrželi omylem a nejste jejím 
zamýšleným příjemcem, informujte o této skutečnosti bezodkladně 
odesílatele zprávy, odstraňte ji, včetně případných příloh, z Vašeho 
systému a dále zamezte, aby se tato dostala do dispozice dalším 
neoprávněným osobám.
ČD - Telematika a.s. tímto dále informuje adresáta emailu, že poptává-li 
tímto emailem po adresátovi plnění, činí tak vůči němu pouze nezávaznou 
poptávku a toto její jednání nelze považovat za příslib uzavření smlouvy, 
neuvede-li odesílatel tohoto emailu jinak. ČD - Telematika a.s. si 
vyhrazuje právo s adresátem smlouvu neuzavřít. ČD - Telematika a.s., v 
souladu s § 1740 odst. 3 občanského zákoníku, nepřipouští přijetí návrhu 
na uzavření smlouvy s dodatkem nebo s odchylkou. ČD - Telematika a.s. 
nepřipouští uzavření smlouvy odkazující na obchodní podmínky, které si 
podle § 1751 odst. 2 občanského zákoníku vzájemně odporují. ČD - 
Telematika a.s., v souladu s § 1758 občanského zákoníku, nepřipouští 
uzavření smlouvy a její změny či doplnění v jiné než písemné formě; 
vzhledem k tomu se nepoužije § 1757 občanského zákoníku.
Ochrana osobních údajů je v ČD - Telematika a.s. řešena v souladu s 
právními předpisy EU ("GDPR") a ČR ("zákon o ochraně osobních údajů") 
prostřednictvím dokumentů zajišťujících souladnost s danými právními 
předpisy, a to: Podmínky ochrany osobních údajů a Zásady zpracování 
osobních údajů, oba dokumenty ke stažení na www.cdt.cz/soubory-ke-stazeni.




^ permalink  raw  reply  [nested|flat] 2+ messages in thread

* Re: [email protected]
  2026-03-03 10:02 [email protected] [email protected]
@ 2026-03-05 04:32 ` Tatsuo Ishii <[email protected]>
  0 siblings, 0 replies; 2+ messages in thread

From: Tatsuo Ishii @ 2026-03-05 04:32 UTC (permalink / raw)
  To: [email protected]; +Cc: [email protected]

Hi,

From: [email protected]
Subject: [email protected]
Date: Tue, 3 Mar 2026 11:02:03 +0100
Message-ID: <[email protected]>

> Hello,
> i  have a problem with error which occurs on my pgpool cluster. The log 
> messages i collected for this error :
> 
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: ERROR:  unable 
> to write data to frontend
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: DETAIL: 
> pool_flush failed
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOCATION: 
> pool_stream.c:539
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOG:  frontend 
> disconnection: session time: 0:00:32.989 user=network_app_prod_adm 
> database=network_app_prod host=cdis000phaux173.cdis.cz port=63675
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOCATION: 
> child.c:2110
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOG:  DB node 
> id: 0 backend pid: 3935771 statement: DISCARD ALL
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOCATION: 
> pool_proto_modules.c:3802
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOG:  DB node 
> id: 2 backend pid: 199834 statement: DISCARD ALL
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOCATION: 
> pool_proto_modules.c:3802
> 2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: WARNING: 
> packet kind of backend 2 ['Z'] does not match with main/majority nodes 
> packet kind ['D']
> 2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: LOCATION: 
> pool_process_query.c:3713
> 2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: FATAL:  failed 
> to read kind from backend
> 2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: DETAIL:  kind 
> mismatch among backends. Possible last query was: "DISCARD ALL" kind 
> details are: 0[D] 2[Z]
> 2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: HINT:  check 
> data consistency among db nodes
> 2026-03-02 15:30:21.768: PostgreSQL JDBC Driver pid 197272: LOCATION: 
> pool_process_query.c:3810
> 
> The customer complaints that the statement he is trying to send to 
> database (INSERT) is basicaly not entered into the database. This error 
> happenes several times a day, 
> My version of pgpool and database : 
> 
> postgres@postgre-cdis-clu-pha-db3:/var/lib/pgsql/data/log> pgpool -version
> pgpool-II version 4.5.10 (hotooriboshi)
> 
> postgres@postgre-cdis-clu-pha-db3:/var/lib/pgsql/data/log> psql -version
> psql (16.11)
> Type "help" for help.
> 
> The configuration of cluster:
> 
> postgres@postgre-cdis-clu-pha-db3:/var/lib/pgsql/data/log> 
> pcp_watchdog_info -h 10.31.8.28 -p 9898 -U pgpool
> 3 3 YES postgre-cdis-clu-pha-db3:9999 Linux postgre-cdis-clu-pha-db3 
> postgre-cdis-clu-pha-db3
> 
> postgre-cdis-clu-pha-db3:9999 Linux postgre-cdis-clu-pha-db3 
> postgre-cdis-clu-pha-db3 9999 9000 4 LEADER 0 MEMBER
> postgre-cdis-clu-pha-db1:9999 Linux postgre-cdis-clu-pha-db1 
> postgre-cdis-clu-pha-db1 9999 9000 7 STANDBY 0 MEMBER
> postgre-cdis-clu-pha-db2:9999 Linux postgre-cdis-clu-pha-db2 
> postgre-cdis-clu-pha-db2 9999 9000 7 STANDBY 0 MEMBER
> 
> postgres@postgre-cdis-clu-pha-db3:/var/lib/pgsql/data/log> psql -h 
> 10.31.8.28 -p 9999 -U pgpool postgres -c "show pool_nodes"
>  node_id |         hostname         | port | status | pg_status | 
> lb_weight |  role   | pg_role | select_cnt | load_balance_node | 
> replication_delay | replication_state | replicati
> on_sync_state | last_status_change
> ---------+--------------------------+------+--------+-----------+-----------+---------+---------+------------+-------------------+-------------------+-------------------+----------
> --------------+---------------------
>  0       | postgre-cdis-clu-pha-db1 | 5432 | up     | up        | 0.333333 
>  | standby | standby | 14069796   | false             | 0 | streaming    | 
> async
>               | 2026-03-02 15:28:50
>  1       | postgre-cdis-clu-pha-db2 | 5432 | up     | up        | 0.333333 
>  | standby | standby | 13284878   | true              | 0 | streaming    | 
> async
>               | 2026-03-02 15:28:50
>  2       | postgre-cdis-clu-pha-db3 | 5432 | up     | up        | 0.333333 
>  | primary | primary | 15253310   | false             | 0 |    |
>               | 2026-03-02 15:28:50
> (3 rows)
> 
> There are no errors at database level in the database log.
> Any advice how to solve this ?

It seems your java disconnects to pgpool. I suggest to inspect the
application log and check why the application disconnected,

> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: ERROR:  unable 
> to write data to frontend
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: DETAIL: 
> pool_flush failed
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOCATION: 
> pool_stream.c:539
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOG:  frontend 
> disconnection: session time: 0:00:32.989 user=network_app_prod_adm 
> database=network_app_prod host=cdis000phaux173.cdis.cz port=63675
> 2026-03-02 15:30:21.767: PostgreSQL JDBC Driver pid 197272: LOCATION: 
> child.c:2110

Best regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp






^ permalink  raw  reply  [nested|flat] 2+ messages in thread


end of thread, other threads:[~2026-03-05 04:32 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2026-03-03 10:02 [email protected] [email protected]
2026-03-05 04:32 ` Tatsuo Ishii <[email protected]>

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox