[pgpool-general: 1674] Re: pgpool: connection cannot be released

[manphis chen]

Dear sir,

Sorry for the missing information.

Actually my statement includes "nextval" keyword.

My statement looks like:
pstmt = conn.prepareStatement("insert into table_name (id) values
(nextval('seq'))");

By using this kind of statement, I can re-produce the hang-on situation.

Many thanks for your help




best regards.




2013/5/2 Tatsuo Ishii <ishii at postgresql.org>

> > Hello All,
> >
> > I forget to install regclass in postgresql server.
> >
> > When I send a query which needs a function belonging to regclass (e.g.
> > nextval), pgpool can receive a message from backend.
> > The message looks like: cannot access file libdir/pgpool-regclass: no
> such
> > file or directory.
> >
> > When this happens, the connection from the client cannot be release.
> > If I keep requesting the same query iteratively, the number of
> connections
> > reaches the maximum value, and then all connections are occupied and no
> > connection can be accepted.
> >
> > I know that I should install regclass in postgresql server, but my
> question
> > is: Is that correct for pgpool that the connection cannot be released
> after
> > some error happen at backend?
>
> Did not reproduce here. I renamed pgpool-regclass.so and ran simple
> SELECT. Here are logs I observed but no lock up happens.
>
> 2013-05-02 14:08:24 LOG:   pid 4311: do_query: error message from backend:
> could not access file "$libdir/pgpool-regclass": No such file or directory
> 2013-05-02 14:08:24 LOG:   pid 4311: DB node id: 0 backend pid: 4335
> statement: SELECT count(*) FROM pg_catalog.pg_class AS c, pg_attribute AS a
> WHERE c.relname = 'pg_class' AND a.attrelid = c.oid AND a.attname =
> 'relistemp'
> 2013-05-02 14:08:24 LOG:   pid 4311: DB node id: 0 backend pid: 4335
> statement: SELECT count(*) FROM pg_class AS c, pg_namespace AS n WHERE
> c.relname = 'pg_class' AND c.relnamespace = n.oid AND n.nspname ~
> '^pg_temp_'
> 2013-05-02 14:08:24 LOG:   pid 4311: DB node id: 0 backend pid: 4335
> statement: SELECT count(*) FROM pg_catalog.pg_class AS c,
> pg_catalog.pg_attribute AS a WHERE c.relname = 'pg_class' AND a.attrelid =
> c.oid AND a.attname = 'relpersistence'
> 2013-05-02 14:08:24 LOG:   pid 4311: DB node id: 0 backend pid: 4335
> statement: SELECT count(*) FROM pg_catalog.pg_class AS c WHERE c.oid =
> pgpool_regclass('pg_class') AND c.relpersistence = 'u'
> 2013-05-02 14:08:24 LOG:   pid 4311: DB node id: 0 backend pid: 4335
> statement: select * from pg_class limit 1;
> 2013-05-02 14:11:23 LOG:   pid 4311: DB node id: 0 backend pid: 4335
> statement:  DISCARD ALL
> 2013-05-02 14:11:23 LOG:   pid 4311: DB node id: 1 backend pid: 4336
> statement:  DISCARD ALL
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese: http://www.sraoss.co.jp
>



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