Just a thought. When you ED VOC Dummy, you are creating a new record, where
you are locking the Key to not be used by another process rather than locking
the record. I am not sure where the locks are on the file system, but I
wonder if Dummy already existed before you edited, whether this would be
different. Also it would be worth test the difference of using READL and READU.
[mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of Charles Stevenson
Sent: Sunday, 30 October 2011 10:22 AM
To: Charles Stevenson
Cc: U2 Users List
Subject: Re: [U2] [UV] LIST.READU EVERY's "waiters" when there are writes w/o
I hate to bring it up after 50+ responses over 4 days, but . . .
Did anyone ever actually run my little test?
On something other than my UV10.2/Win? Unix? Before UV10.2?
Knowing that would help me assess the size & age of our problem.
I still think that in times past, a waiterfor a lockvia WRITE or DELETEwould
show up at the 3rd section of LIST.READU EVERY, even as the typical READU (or
FILELOCK, RECORDLOCKU) does.
The original test was request was this:
On 10/24/2011 4:11 PM, Charles Stevenson wrote:
> UV 10.2.10 on Windows is behaving differently from what I recall.
> Are my expectations out of line?
> Suppose Session A holds a readu lock; and Session B attempts a WRITE
> to same record withOUT!!! 1st explicitly getting the readu lock.
> Session B waits for Session A to release the lock before writing the
> While Session B is waiting, does it show up as a "waiter" in
> LIST.READU EVERY?
> I expected so, but it doesn't.
> Session A Session B
> _____________________________ ___________________
> 1A. ED VOC DUMMY
> (this sets the readu lock.)
> 2A. (stay in editor) 2B. run this:
> 01: OPEN 'VOC' TO F ELSE STOP
> 02: ***READU REC FROM F, 'DUMMY'
> ELSE NULL
> 03: WRITE '' TO F, 'DUMMY'
> 3A. Within ED:
> XEQ LIST.READU EVERY
> If I UN-comment line 2, LIST.READU EVERY shows something like this:
> Active Read Waiters: Owner Waiter
> Device.... Inode.... Userno Userno
> 746117947 232860913 6116 3396
> But when I comment out line 2, LIST.READU is silent.
> I have not yet explored what the deadlock daemon does.
> P.S. Yes, yes, "Bad Form", "Legacy Software", 20 min wait is
> configurable, . . . we can talk later.
"Later" is already past. I'm not talking about that P.S. again!
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