Re: BUG #10888: application is getting hanged in the poll() function of libpq.so.

Hi Tom,=20

Thanks for your response. But at server side it is showing the following be=
havior .
I am running a single query at this moment.

INSERT INTO eventLogEntry (object, method, bgwUser, time, realUser, host, a=
pplication, tableIndex  ) VALUES (E'Server', E'Start', E'bgw', E'2014051212=
2404', NULL, NULL, NULL, 539  );

So not able to understand whats wrong with the database that it is unable t=
o process this simple insert query.
At the same time if drop the index and recreate the table then this issue i=
s resolved. But obviously this is not a feasible solution in live environme=
nt. Plz see if you can provide some help.

>pstack 16950
#0  0x00000000006dc1da in hash_search ()
#1  0x000000000060e430 in LockAcquireExtended ()
#2  0x000000000060c46e in XactLockTableWait ()
#3  0x0000000000476bc6 in _bt_doinsert ()
#4  0x0000000000479882 in btinsert ()
#5  0x00000000006d6d25 in FunctionCall6Coll ()
#6  0x00000000004743c7 in index_insert ()
#7  0x0000000000563375 in ExecInsertIndexTuples ()
#8  0x000000000056eba3 in ExecModifyTable ()
#9  0x000000000055a863 in ExecProcNode ()
#10 0x0000000000559871 in standard_ExecutorRun ()
#11 0x000000000062037f in ProcessQuery ()
#12 0x00000000006205a7 in PortalRunMulti ()
#13 0x0000000000621068 in PortalRun ()
#14 0x000000000061dc5b in exec_simple_query ()
#15 0x000000000061e464 in PostgresMain ()
#16 0x00000000005e38dc in ServerLoop ()
#17 0x00000000005e45dc in PostmasterMain ()
#18 0x0000000000588dbe in main ()

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]=20
Sent: Monday, July 07, 2014 8:24 PM
To: Mitu Verma
Cc: pgsql-bugs@postgresql.org
Subject: Re: [BUGS] BUG #10888: application is getting hanged in the poll()=
 function of libpq.so.

mitu.verma@ericsson.com writes:
> Application gets hanged while making a query to the PostgreSql database.

> I reproduced the issues on our testbed by making a simple C program=20
> which makes a synchronous connection with the DB.

> Pstack is showing the following error when the application is hang=20
> (see
> below)

> Now as it looks that it is getting hanged in the poll() function of=20
> libpq.so.

That looks like it's just waiting for the server to respond.  You sure you =
didn't simply issue a very long-running query?  Check to see if the connect=
ed backend process is accumulating CPU time and/or I/O activity.

            regards, tom lane