RE: Pg10 : Client Configuration for Parallelism ?

As answered to Andreas Kretschmer all settings are identical.

I have made some other tests, even testing a basic jdbc program (open connection, execute statement, display result, close connection)

Here are the logs (with log_error_verbosity = verbose) :

<DBEAVER>
2019-04-17 11:30:42 CEST;35895;thedbuser;thedb;00000;LOG: 00000: execute <unnamed>: SELECT COUNT(1) FROM big_table
2019-04-17 11:30:42 CEST;35895;thedbuser;thedb;00000;LOCATION: exec_execute_message, postgres.c:1959
2019-04-17 11:31:08 CEST;35895;thedbuser;thedb;00000;LOG: 00000: duration: 25950.908 ms
2019-04-17 11:31:08 CEST;35895;thedbuser;thedb;00000;LOCATION: exec_execute_message, postgres.c:2031

<BASIC JDBC>
2019-04-17 11:31:20 CEST;37257;thedbuser;thedb;00000;LOG: 00000: execute <unnamed>: SELECT COUNT(1) FROM big_table
2019-04-17 11:31:20 CEST;37257;thedbuser;thedb;00000;LOCATION: exec_execute_message, postgres.c:1959
2019-04-17 11:31:32 CEST;37257;thedbuser;thedb;00000;LOG: 00000: duration: 11459.943 ms
2019-04-17 11:31:32 CEST;37257;thedbuser;thedb;00000;LOCATION: exec_execute_message, postgres.c:2031

<PGADMIN4>
2019-04-17 11:32:56 CEST;37324;thedbuser;thedb;00000;LOG: 00000: statement: SELECT COUNT(1) FROM big_table;
2019-04-17 11:32:56 CEST;37324;thedbuser;thedb;00000;LOCATION: exec_simple_query, postgres.c:940
2019-04-17 11:33:08 CEST;37324;thedbuser;thedb;00000;LOG: 00000: duration: 11334.677 ms
2019-04-17 11:33:08 CEST;37313;thedbuser;thedb;00000;LOG: 00000: statement: SELECT oid, format_type(oid, NULL) AS typname FROM pg_type WHERE oid IN (20) ORDER BY oid;
2019-04-17 11:33:08 CEST;37313;thedbuser;thedb;00000;LOCATION: exec_simple_query, postgres.c:940
2019-04-17 11:33:08 CEST;37313;thedbuser;thedb;00000;LOG: 00000: duration: 0.900 ms
2019-04-17 11:33:08 CEST;37313;thedbuser;thedb;00000;LOCATION: exec_simple_query, postgres.c:1170

I don’t see any difference a part from the query duration. Note that while monitoring the server I saw that there was parallelism with JDBC program and PGAdmin4, but not with Dbeaver. And the JDBC driver is the same in both “Basic JDBC” and DBeaver.

Regards.

Laurent.

De : Andreas Joseph Krogh [mailto:andreas(at)visena(dot)com]
Envoyé : mercredi 17 avril 2019 11:08
À : pgsql-performance(at)lists(dot)postgresql(dot)org
Objet : Sv: Pg10 : Client Configuration for Parallelism ?

På onsdag 17. april 2019 kl. 08:30:28, skrev <laurent(dot)dechambe(at)orange(dot)com<mailto:laurent(dot)dechambe(at)orange(dot)com>>:
Hi,

I am working on PostgreSQL 10.5 and I have a discrepancy between clients regarding parallelism feature.

For a simple query (say a simple SELECT COUNT(*) FROM BIG_TABLE), I can see PostgreSQL use parallelism when the query is launched from psql or PgAdmin4. However the same query launched with DBeaver (ie connected through JDBC) does not use parallelism.

SELECT current_setting('max_parallel_workers_per_gather') gives 10 from my session.

Is there a client configuration that prevents from using parallelism ?

Thanks.

Laurent

Set in postgresql.conf:

log_statement = 'all'

reload settings and check the logs for what statemets are acutally issued.

--
Andreas Joseph Krogh
CTO / Partner - Visena AS
Mobile: +47 909 56 963
andreas(at)visena(dot)com<mailto:andreas(at)visena(dot)com>
www.visena.com<https://www.visena.com>
[cid:image001(dot)png(at)01D4F510(dot)5C6B6150]<https://www.visena.com>

_________________________________________________________________________________________________________________________

Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc
pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler
a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration,
Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci.

This message and its attachments may contain confidential or privileged information that may be protected by law;
they should not be distributed, used or copied without authorisation.
If you have received this email in error, please notify the sender and delete this message and its attachments.
As emails may be altered, Orange is not liable for messages that have been modified, changed or falsified.
Thank you.