Re: PQexec does not return.

Hi All,

Found the problem. This was caused by a memory leak in our application.

Regards
Steve Martin

Steve Martin wrote:

> Hi All,
>
> We have an intermittent problem where PQexec does not seem to return
> even though the server seems to have sent the results.
>
> From the gdb output , the sql statement can be seen, and from the log,
> the result can be seen to be sent. Both process are running on the
> same machine. Version of postgres and other info:
>
> 1. Postgres Version 8.1.4
> 2. Machine HP rx4640
> 3. OS: HPUX 11.23
> 4. Mem 8G
>
>
> Has anyone seen this type of problem before, can it be cause by a
> TCP/IP communication failure?
>
>
> From gdb:
>
> % /opt/langtools/bin/gdb /path/name -p 3587
> HP gdb 5.2 for HP Itanium (32 or 64 bit) and target HP-UX 11.2x.
> Copyright 1986 - 2001 Free Software Foundation, Inc.
> Hewlett-Packard Wildebeest 5.2 (based on GDB) is covered by the
> GNU General Public License. Type "show copying" to see the
> conditions to
> change it and/or distribute copies. Type "show warranty" for
> warranty/support.
> ..
> Attaching to program: /path/name, process 3587
>
> warning: No unwind information found.
> Skipping this library /usr/lib/hpux32/libcl.so.1.
>
> 0x60000000c0342810:0 in _poll_sys+0x30 () from
> /usr/lib/hpux32/libc.so.1
> (gdb) bt
> #0 0x60000000c0342810:0 in _poll_sys+0x30 () from
> /usr/lib/hpux32/libc.so.1
> #1 0x60000000c03553e0:0 in poll+0x160 () from
> /usr/lib/hpux32/libc.so.1
> #2 0x60000000cefa75b0:0 in pqSocketCheck+0xb00 ()
> from /usr/local/pgsql/lib/libpq.so.4
> #3 0x60000000cefa77c0:0 in pqWaitTimed+0x40 ()
> from /usr/local/pgsql/lib/libpq.so.4
> #4 0x60000000cefa7890:0 in pqWait+0x40 () from
> /usr/local/pgsql/lib/libpq.so.4
> #5 0x60000000cefa53b0:0 in PQgetResult+0x180 ()
> from /usr/local/pgsql/lib/libpq.so.4
> #6 0x60000000cefa56f0:0 in PQexecFinish+0x40 ()
> from /usr/local/pgsql/lib/libpq.so.4
> #7 0x60000000c1c83870:0 in DBIFPostgreSelect::getRecord
> (this=0x40114840)
> at DBIFPostgre.C:1688
> #8 0x60000000c1c73d20:0 in DBIFPostgreSelect::selectNext
> (this=0x40114840,
> rst=(at)0x7fff5210) at DBIFPostgre.C:1902
> #9 0x60000000c1c64b90:0 in DBIFSelect::selectNext (this=0x7fff5240,
> rst=(at)0x7fff5210) at DBIF.C:2704
> #10 0x404ff00:0 in TableStatus::checkDeferredTR (this=0x403104c0)
> at DbSContTable.C:1468
> #11 0x405b430:0 in TableStatusManager::checkDeferredTR
> (this=0x400bde90)
> at DbSContTable.C:3146
> #12 0x4068960:0 in Controller::go (this=0x7fffc320) at
> DbSController.C:1950
> #13 0x406b1b0:0 in main (argc=1, argv=0x7fffed74) at DbSContMain.C:137
> (gdb) q
> The program is running. Quit anyway (and detach it)? (y or n) y
> Detaching from program: /path/name, process 3587
>
> % /opt/langtools/bin/gdb /path/name -p 3587
> HP gdb 5.2 for HP Itanium (32 or 64 bit) and target HP-UX 11.2x.
> Copyright 1986 - 2001 Free Software Foundation, Inc.
> Hewlett-Packard Wildebeest 5.2 (based on GDB) is covered by the
> GNU General Public License. Type "show copying" to see the
> conditions to
> change it and/or distribute copies. Type "show warranty" for
> warranty/support.
> ..
> Attaching to program: /path/name, process 3587
>
> warning: No unwind information found.
> Skipping this library /usr/lib/hpux32/libcl.so.1.
>
> 0x60000000c0342810:0 in _poll_sys+0x30 () from
> /usr/lib/hpux32/libc.so.1
> (gdb) up
> #1 0x60000000c03553e0:0 in poll+0x160 () from
> /usr/lib/hpux32/libc.so.1
> (gdb) up
> #2 0x60000000cefa75b0:0 in pqSocketCheck+0xb00 ()
> from /usr/local/pgsql/lib/libpq.so.4
> (gdb) up
> #3 0x60000000cefa77c0:0 in pqWaitTimed+0x40 ()
> from /usr/local/pgsql/lib/libpq.so.4
> (gdb) up
> #4 0x60000000cefa7890:0 in pqWait+0x40 () from
> /usr/local/pgsql/lib/libpq.so.4
> (gdb) up
> #5 0x60000000cefa53b0:0 in PQgetResult+0x180 ()
> from /usr/local/pgsql/lib/libpq.so.4
> (gdb) up
> #6 0x60000000cefa56f0:0 in PQexecFinish+0x40 ()
> from /usr/local/pgsql/lib/libpq.so.4
> (gdb) up
> #7 0x60000000c1c83870:0 in DBIFPostgreSelect::getRecord
> (this=0x40114840)
> at DBIFPostgre.C:1688
> 1688 myResultExecPrepare =
> PQexec(myConnection->conn, seleStmt);
> (gdb) p seleStmt
> $1 = "SELECT * FROM T_AM_TERM_BILLING WHERE (TR_STATUS =
> 'DEFERRED') AND ((DOWNLOAD_DATE < 20070108) OR ((DOWNLOAD_DATE =
> 20070108) AND (DOWNLOAD_TIME < 203744)))", '\000' <repeats 43 times>
> (gdb) q
> The program is running. Quit anyway (and detach it)? (y or n) y
> Detaching from program: /path/name, process 3587
>
>
> From postgres log
>
> 2007-01-08 20:37:44.839 NZDT ain(at)[local]%smf>LOG: statement:
> select pg_get_indexdef(indexrelid) from pg_index where ind
> relid = ( select oid from pg_class where relname =
> 't_am_registration_db')
> 2007-01-08 20:37:44.840 NZDT ain(at)[local]%smf>LOG: duration: 0.347 ms
> 2007-01-08 20:37:44.840 NZDT ain(at)[local]%smf>LOG: statement:
> SELECT * FROM T_AM_REGISTRATION_DB WHERE (TR_STATUS = 'DEF
> ERRED') AND ((DOWNLOAD_DATE < 20070108) OR ((DOWNLOAD_DATE =
> 20070108) AND (DOWNLOAD_TIME < 203744)))
> 2007-01-08 20:37:44.841 NZDT ain(at)[local]%smf>LOG: duration: 0.792 ms
> 2007-01-08 20:37:44.841 NZDT ain(at)[local]%smf>LOG: statement:
> select attname, attnotnull, atttypid, atttypmod, format_ty
> pe(atttypid, atttypmod) as data_type from pg_attribute where
> attnum > 0 and atttypid > 0 and attrelid = ( select oid fro
> m pg_class where relname = 't_am_term_billing') order by attnum
> 2007-01-08 20:37:44.842 NZDT ain(at)[local]%smf>LOG: duration: 0.778 ms
> 2007-01-08 20:37:44.842 NZDT ain(at)[local]%smf>LOG: statement:
> select pg_get_indexdef(indexrelid) from pg_index where ind
> relid = ( select oid from pg_class where relname =
> 't_am_term_billing')
> 2007-01-08 20:37:44.842 NZDT ain(at)[local]%smf>LOG: duration: 0.346 ms
> 2007-01-08 20:37:44.842 NZDT ain(at)[local]%smf>LOG: statement:
> SELECT * FROM T_AM_TERM_BILLING WHERE (TR_STATUS = 'DEFERRED') AND
> ((DOWNLOAD_DATE < 20070108) OR ((DOWNLOAD_DATE = 20070108) AND
> (DOWNLOAD_TIME < 203744)))
> 2007-01-08 20:37:44.843 NZDT ain(at)[local]%smf>LOG: duration: 1.165 ms
> 2007-01-08 20:50:02.026 NZDT @%>LOG: autovacuum: processing
> database "template1"
> 2007-01-08 21:50:02.036 NZDT @%>LOG: autovacuum: processing
> database "smf"
> 2007-01-08 22:50:02.084 NZDT @%>LOG: autovacuum: processing
> database "postgres"
> 2007-01-08 23:50:02.104 NZDT @%>LOG: autovacuum: processing
> database "template1"
> 2007-01-09 00:40:01.090 NZDT [unknown](at)%[unknown]>LOG: connection
> received: host=[local]
> 2007-01-09 00:40:01.091 NZDT ain(at)[local]%smf>LOG: connection
> authorized: user=ain database=smf
> 2007-01-09 00:40:01.093 NZDT ain(at)[local]%smf>LOG: statement:
> select attname, attnotnull, atttypid, atttypmod, format_ty
> pe(atttypid, atttypmod) as data_type from pg_attribute where
> attnum > 0 and atttypid > 0 and attrelid = ( select oid fro
> m pg_class where relname = 'com_node_host') order by attnum
> 2007-01-09 00:40:01.097 NZDT ain(at)[local]%smf>LOG: duration: 3.788 ms
>
> Regards
> Steve Martin