I would think that because you are not trying to obtain the lock in a
WRITE statement, it would not be classified as a waiter.  True, it's
waiting because of the lock but by not trying to obtain the lock, it's
only waiting for the blockage to clear.  If it were to be classified as
a waiter then I would expect to see a LOCKED clause on the WRITE
statement like there is on the READU.  For that matter, I'd expect to
see a WRITEU command as well and the standard WRITE to completely ignore
locking.

Just my guess, though.

BobW

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Charles
Stevenson
Sent: Monday, October 24, 2011 2:12 PM
To: U2 Users List
Subject: [U2] [UV] LIST.READU EVERY's "waiters" when there are writes
w/o explicit readu.

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
record.

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 STOPM 
'nope'
                                     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.

TIA,
cds


P.S. Yes, yes, "Bad Form", "Legacy Software", 20 min wait is 
configurable, . . . we can talk later.

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