20 points to anyone who is old enough to remember *why* we couldn't rely on the Locked clause.
-----Original Message----- From: Charles Stevenson <stevenson.c...@gmail.com> To: Paul Wilson <sfr192...@yahoo.com>; U2 Users List <firstname.lastname@example.org> Sent: Mon, Oct 24, 2011 5:28 pm Subject: Re: [U2] [UV] LIST.READU EVERY's "waiters" when there are writes w/o explicit readu. Come to think of it, I think customizing CSC's MHC s/w was the 1st time ever fought this fight. Before that, I had always programmed under a standard that demanded a EADU before a WRITE. And every READU needed a LOCKED clause. cds On 10/24/2011 6:57 PM, Paul Wilson wrote: That little company called CSC does/did not use readu's - they put login id in ield 1 and used that for a 'locking' situation. ________________________________ From: "Woodward, Bob"<bob_woodw...@k2sports.com> To: U2 Users List<email@example.com> Sent: Monday, October 24, 2011 7:06 PM Subject: Re: [U2] [UV] LIST.READU EVERY's "waiters" when there are writes w/o xplicit readu. Oh I agree! I was just thinking round-robin that if we're going to talk about adding a LOCKED clause to the WRITE statement, matching the structure of READU, then we ought to have a WRITEU, too. Didn't say I liked the idea.... -----Original Message----- From: u2-users-boun...@listserver.u2ug.org [mailto:u2-users-boun...@listserver.u2ug.org] On Behalf Of Mecki Foerthmann Sent: Monday, October 24, 2011 3:30 PM To: firstname.lastname@example.org Subject: Re: [U2] [UV] LIST.READU EVERY's "waiters" when there are writes w/o explicit readu. Now why would anybody want to use a WRITE without a READU? I can possibly understand that somebody would want to do it with a WRITEV (i.e writing a flag on a record) but WRITE? And WRITE totally ignoring locking would be outright stupid. On 24/10/2011 22:28, Woodward, Bob wrote: > 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: u2-users-boun...@listserver.u2ug.org > [mailto:u2-users-boun...@listserver.u2ug.org] 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. ______________________________________________ 2-Users mailing list 2-us...@listserver.u2ug.org ttp://listserver.u2ug.org/mailman/listinfo/u2-users _______________________________________________ U2-Users mailing list U2-Users@listserver.u2ug.org http://listserver.u2ug.org/mailman/listinfo/u2-users