SOCK_wait_for_ready function call caused a query to get stuck

["tamanna madaan" <tamanna.madan@xxxxxxxxxxxxxxx>]

Hi All

 

 I am using postgres-8.4.0 and psqlodbc-08.03.0400-1 and unixODBC-2.2.14-000.01 driver to connect
to the database. One of the queries I executed from my application have got stuck for an
indefinite amount of time causing my application to hang. So I cored the application. The
core file gives a backtrace which shows it got stuck while waiting for a socket to get
ready as follows :

 

(gdb) bt
#0  0x00007f1c3e5ed366 in poll () from /lib64/libc.so.6
#1  0x00007f1c3a82d0a5 in SOCK_wait_for_ready (sock=0x7f1be67ff720, output=0, retry_count=1) at socket.c:531
#2  0x00007f1c3a82d8c3 in SOCK_get_next_byte (self=0x7f1be67ff720, peek=0) at socket.c:940
#3  0x00007f1c3a82db92 in SOCK_get_id (self=0x7f1be67ff720) at socket.c:696
#4  0x00007f1c3a8090ca in CC_send_query_append (self=0x7f1be68bf430, query=<value optimized out>, qi=0x0, flag=<value optimized out>, stmt=0x0,
    appendq=<value optimized out>) at connection.c:2498
#5  0x00007f1c3a818ae5 in PGAPI_Transact (henv=0x0, hdbc=0x7f1be68bf430, fType=0) at execute.c:1143
#6  0x00007f1c3a8424ec in SQLEndTran (HandleType=<value optimized out>, Handle=0x7f1be68bf430, CompletionType=-1) at odbcapi30.c:178
#7  0x00007f1c3f62fa2b in SQLEndTran (handle_type=<value optimized out>, handle=0x7f1beff16b90, completion_type=0) at SQLEndTran.c:360

One other thread of the same process was also stuck :

 

(gdb) bt
#0  0x00007f1c3e5ed366 in poll () from /lib64/libc.so.6
#1  0x00007f1c3a82d0a5 in SOCK_wait_for_ready (sock=0x2bcde60, output=0, retry_count=1) at socket.c:531
#2  0x00007f1c3a82d8c3 in SOCK_get_next_byte (self=0x2bcde60, peek=0) at socket.c:940
#3  0x00007f1c3a82db92 in SOCK_get_id (self=0x2bcde60) at socket.c:696
#4  0x00007f1c3a8090ca in CC_send_query_append (self=0x2bd13a0, query=<value optimized out>, qi=0x0, flag=<value optimized out>, stmt=0x7f1bf766c380,
    appendq=<value optimized out>) at connection.c:2498
#5  0x00007f1c3a836c94 in SC_execute (self=0x7f1bf766c380) at statement.c:1879
#6  0x00007f1c3a81907e in Exec_with_parameters_resolved (stmt=0x7f1bf766c380, exec_end=0x7f1c2c59e4c0) at execute.c:386
#7  0x00007f1c3a81a600 in PGAPI_Execute (hstmt=0x7f1bf766c380, flag=<value optimized out>) at execute.c:1070
#8  0x00007f1c3a83fd82 in SQLExecute (StatementHandle=0x7f1bf766c380) at odbcapi.c:374
#9  0x00007f1c3f630c77 in SQLExecute (statement_handle=0x7f1be4b069e0) at SQLExecute.c:283

I had the same issue while using postgres-8.1.2 and was advised to upgrade postgres.

But upgrading the postgres version didn't resolve the issue  .
There doesn't seem to be any locking issue either .

 

Can anyone please shed some light on this issue .

Thanks...
Tamanna