Re: Questions regarding notify processing.

This thing is hanging up in PQnotifies. I have added a simple fprintf
statement to the following function:
void CheckForNotifies (Controls *ctrl)
{
#ifndef CALL_TRACE
    fprintf (stderr, "%s: %d: %s (%s)\n", __FILE__, __LINE__,
            __FUNCTION__, ctrl->table);
#endif

    PQflush (ctrl->sys->conn);              // always flush it first ;o)

    PQconsumeInput (ctrl->sys->conn);
    fprintf (stderr, "just before call to PQnotifies...\n");
    while ((ctrl->notify = PQnotifies (ctrl->sys->conn)) != NULL)
    {
#ifndef DEBUG
        fprintf (stderr,
        "%s: ASYNC NOTIFY of '%s' from backend pid '%d' received\n",
                 __FUNCTION__, ctrl->notify->relname,
                 ctrl->notify->be_pid);
#endif
        /* If you are interested in receiving any NOTICE data, you will
         * have to have this function defined locally. */
        if (ctrl->main->backEndNotify)
        {
            void (*p) () = (void *) ctrl->main->backEndNotify;
            (*p) (ctrl);                    // call the function
        }
        PQfreemem (ctrl->notify);           // free the memory
    }
}
The fprintf statement prints and nothing else happens. Observe:
move/move.c: 2072: preMenuActFunc (move::save_b)
move/move.c: 2718: save_SQL ()
move/move.c: 2798: save_SQL ()
move/move.c: 2816: restoreState ()
utility/global.c: 1804: CheckForNotifies (move)
just before call to PQnotifies...

And that is where it sits until I send a message notification from a separate
client (plsql). When the message is sent, the process continues. Is this a
bug?  Did anybody look at the stack trace is sent? I don't have the expertise
to analyze it.

TIA

On Friday 25 February 2005 06:00 am, Terry Lee Tucker saith:
> See partial output from strace below. On this particular run, the command
> locked up during the second edit operation. The notify message,
> move_update, was delivered, but the PQsendquery never returns.
>
> Any ideas Tom?
>
> recv(3, "A\0\0\0\25\0\0~3move_update\0\0C\0\0\0\rUPDAT"..., 16384, 0) = 42
> write(2, "CheckForNotifies: ASYNC NOTIFY o"..., 82CheckForNotifies: ASYNC
> NOTIFY of 'move_update' from backend pid '32307' received
> ) = 82
> write(2, "main/main.c: 1638: backEndNotify"..., 54main/main.c: 1638:
> backEndNotify (32307: move_update)
> ) = 54
> write(2, "main/main.c: 1655: backEndNotify"..., 43main/main.c: 1655:
> backEndNotify (leaving)
> ) = 43
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> ioctl(4, FIONREAD, [32])                = 0
> read(4, "\34\364_\264\311\4\300\7<\1\0\0\304\243G\22\0\0\0\0\304"..., 32) =
> 32 select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> ioctl(4, FIONREAD, [32])                = 0
> read(4, "\34\364_\264\311\4\300\7\f\1\0\0\305\243G\22\0\4\300\7"..., 32) =
> 32 select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> ioctl(4, FIONREAD, [384])               = 0
> read(4, "\34\364_\264\311\4\300\7\365\0\0\0\306\243G\22\0\0\0\0"..., 384) =
> 384
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> ioctl(4, FIONREAD, [32])                = 0
> read(4, "\226\252_\264\311\4\300\7\311\4\300\7\0\0\0\0\370\0\177"..., 32) =
> 32 write(4, "\2\2\4\0\314\4\300\7\0\10\0\0}\240 \0", 16) = 16
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> write(4, "8\2\4\0\32\0\300\7\0\0\10\0\0\0\0\0>\5\7\0\312\4\300\7"..., 500)
> = 500
> read(4, 0xbffff040, 32)                 = -1 EAGAIN (Resource temporarily
> unavailable)
> select(5, [4], NULL, NULL, NULL)        = 1 (in [4])
> read(4, "\1\1t\264\0\0\0\0\304\364\3\1\370\0\177\1\320\2460\t`\347"..., 32)
> = 32
> write(4, "\17\2\2\0\314\4\300\7", 8)    = 8
> read(4, 0xbffff120, 32)                 = -1 EAGAIN (Resource temporarily
> unavailable)
> select(5, [4], NULL, NULL, NULL)        = 1 (in [4])
> read(4, "\1ku\264\0\0\0\0\257\0\0\0\311\4\300\7\0\0\0\0\0\0\0\0"..., 32) =
> 32 write(4, "B\2\7\0\314\4\300\7\24\0\300\7\256\0@\0\3\1@\0\256\0A\0"...,
> 64) = 64
> read(4, 0xbffff0b0, 32)                 = -1 EAGAIN (Resource temporarily
> unavailable)
> select(5, [4], NULL, NULL, NULL)        = 1 (in [4])
> read(4, "\1tx\264\0\0\0\0\257\0\0\0\311\4\300\7\0\0;\t\260\267\343"..., 32)
> = 32
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> ioctl(4, FIONREAD, [0])                 = 0
> write(4, "F\2\v\0\314\4\300\7\r\0\300\7\252\0<\0^\0\2\0\252\0j\0"..., 44) =
> 44 ioctl(4, FIONREAD, [0])                 = 0
> gettimeofday({1109328767, 349228}, NULL) = 0
> select(5, [3 4], [], [], NULL)          = 1 (in [4])
> ioctl(4, FIONREAD, [32])                = 0
> read(4, "\36\203y\264\0\0\0\0\247\3\300\7]\1`\1\1\0\0\0^\1\0\0%"..., 32) =
> 32 write(4, "\24\0\6\0]\1`\1%\1\0\0\0\0\0\0\0\0\0\0\200\226\230\0", 24) =
> 24 read(4, 0xbffff2f0, 32)                 = -1 EAGAIN (Resource
> temporarily unavailable)
> select(5, [4], NULL, NULL, NULL)        = 1 (in [4])
> read(4, "\1\0z\264\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 32) =
> 32 write(4, "+\0\1\0", 4)                  = 4
> read(4, 0xbffff2e0, 32)                 = -1 EAGAIN (Resource temporarily
> unavailable)
> select(5, [4], NULL, NULL, NULL)        = 1 (in [4])
> read(4, "\1\1{\264\0\0\0\0\311\4\300\7\0\0\0\0\1\0\0\0\2\0\0\0@"..., 32) =
> 32 write(4, "\22\0\25\0]\1`\1%\1\0\0\4\0\0\0 \0\0\0\17\0\0\0^\1\0\0"...,
> 132) = 132
> read(4, 0xbffff440, 32)                 = -1 EAGAIN (Resource temporarily
> unavailable)
> select(5, [4], NULL, NULL, NULL)        = 1 (in [4])
> read(4, "\1\1~\264\0\0\0\0\311\4\300\7\0\0\0\0\0\0\0\0\2\0\0\0@"..., 32) =
> 32 select(5, [3], [], [], {0, 0})          = 0 (Timeout)
> ioctl(4, FIONREAD, [0])                 = 0
> ioctl(4, FIONREAD, [0])                 = 0
> gettimeofday({1109328768, 129317}, NULL) = 0
> select(5, [3 4], [], [], NULL)          = 1 (in [4])
>
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