No hope here?
On Tue, Jul 15, 2014 at 9:49 PM, Sergey Konoplev <gray.ru@xxxxxxxxx> wrote:
> Hi,
>
> PostgreSQL 9.2.7, Linux 2.6.32
>
> Several days ago I found one of my servers out of connections,
> pg_stat_activity showed that everything was waiting for the DROP/ALTER
> INDEX transaction (see the record 2 below), that, as I guess, was
> waiting for the function call (record 1).
>
> -[ RECORD 1 ]----------------------------------
> ts_age | 00:07:15.52997
> state | active
> query_age | 00:07:15.529945
> [...]
> waiting | f
> [...]
> query | select foo(...)
>
> -[ RECORD 2 ]----------------------------------
> ts_age | 00:06:37.844036
> state | active
> query_age | 00:06:37.844036
> [...]
> waiting | t
> [...]
> query | BEGIN;
> SET LOCAL statement_timeout TO 1000;
> DROP INDEX public.idx1;
> ALTER INDEX public.idx2 RENAME TO idx1;
> END;
>
> The interesting thing is that the transaction sets local
> statement_timeout to 1 second and its age was more than 6 minutes. The
> foo() is a complex plpython function containing all the specter of mod
> queries and using dblink(). I didn't manage to reproduce the problem
> with a simple test.
>
> psql -XAte <<EOF
> \timing
> CREATE LANGUAGE plpythonu;
> CREATE TABLE test (t text);
> CREATE INDEX test_idx ON test (t);
> EOF
> sleep 1
> psql -XAte <<EOF &
> \timing
> CREATE OR REPLACE FUNCTION test_plpy()
> RETURNS void LANGUAGE 'plpythonu' AS \$\$
> import time
> plpy.execute("INSERT INTO test VALUES ('a')")
> plpy.execute("ALTER TABLE test ADD i integer")
> plpy.execute("SELECT dblink_exec('dbname=grayhemp', 'DROP TABLE test')")
> plpy.execute("SELECT * FROM dblink('', 'SELECT pg_sleep(3)') AS t (t text)")
> \$\$;
> SELECT test_plpy();
> EOF
> sleep 1
> psql -XAte <<EOF
> \timing
> BEGIN;
> SET LOCAL statement_timeout TO 1000;
> DROP INDEX test_idx;
> END;
> EOF
>
> Any ideas why could it happen and what should I do to prevent this in future?
>
> --
> Kind regards,
> Sergey Konoplev
> PostgreSQL Consultant and DBA
>
> http://www.linkedin.com/in/grayhemp
> +1 (415) 867-9984, +7 (499) 346-7196, +7 (988) 888-1979
> gray.ru@xxxxxxxxx
^^^
--
Kind regards,
Sergey Konoplev
PostgreSQL Consultant and DBA
http://www.linkedin.com/in/grayhemp
+1 (415) 867-9984, +7 (499) 346-7196, +7 (988) 888-1979
gray.ru@xxxxxxxxx
