Path: utzoo!censor!avcocan!can503!story
From: story@can503.UUCP (Robert Story)
Newsgroups: comp.unix.xenix
Subject: Stuck messages in queues with btrieve
Keywords: message queue btrieve
Message-ID: <295@can503.UUCP>
Date: 9 Sep 89 12:02:07 GMT
Reply-To: story@avcocan.UUCP (Robert Story)
Organization: AFS, London, Ontario, CANADA
Lines: 37

We are having a problem with message queues under Xenix.

Software         - Large financial application written in c
Computer Systems - IBM PS2 Model 70-E21 and IBM PS2 Model 70-121, both with
                   IBM 120MB hard drive, IBM 60MB internal tape drive,
		   eight port Stallion serial board with 3 to 6 terminals,
		   serial printer and parallel printer.
Operating System - SCO Xenix System V 2.2.3
Other Software   - Btrieve Record Manager Version 4.10 (80286 version)
                 - Panel Plus Version 1.00c

The problem seems to arise under heavy load, with 3 to 6 users all running the
financial application and printing documents.  A  process will  msg to btrieve
and then set an alarm for 60 seconds and sit on the msgrcv call.  With a large
load one or two of the processes will  get the  alarm signal.   Examination of
the message queues with ipcs shows messages from/to Btrieve in  the queues but
attempts to read these messages with  msgrcv() and   message type  set to zero
show an empty queue.  A call to msgctl() with IPC_STAT reports messages in the
queue but  the  pointers to  the first  and last  messages are  0.  Subsequent
messaging to btrieve carries on as normal.

We do not believe that the problem is with the '286 version of  btrieve.  When
we went to '386 mode for our code  I changed  the appropriate  int's to shorts
for the interfacing code with btrieve.  This has worked since last November in
this manner.  However, the btrieve people in Austin have just sent us the '386
version over the wire and we will be trying that on Monday.  We had problem in
this area last week but tracked it down  to being  a queue  sizing problem and
have now configured the message queues to be more  than adequate.   Of course,
this problem  is  really messy  because one  can not  buy the  source code for
btrieve and it therefore is a large unknown black box.

Your thoughts would be appreciated.  Please e-mail me.  Thanks.
-- 
[ Robert Story    ..{!utzoo!censor,!uunet!zardoz!avcoint}!avcocan!story     ]
[ SnailMail : AFS 201 Queens Avenue London Ontario Canada N6A 1J1           ]
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