VMS 7.3 No Query Record Locking

[Chris Sharman]

VMS, so those disinterested please skip now.

VMS V7.3 (shipping) includes various RMS performance enhancements, which I
believe could give us significant performance improvements.

One interesting one is 'No query locking' which can "be enabled externally,
potentially without any application change".

To be specific: if the application (eg Quiz) uses both of the existing RMS
flags RAB$V_NLK (no lock) and RAB$V_RRL (read regardless of lock), it will
now be possible to avoid record locking altogether, on either a per-process
or system-wide basis. Earlier versions of VMS probe the lock in order to
appropriately return either normal success or 'OK_RRL' (or OK_RLK). This lock
probe carries overhead comparable to locking. This overhead may be avoided
under VMS 7.3 (and it won't know to return OK_RRL or OK_RLK).

My question therefore is:

Do Quiz (& Quick & QTP for readonly files) use either or both of the NLK &
RRL flags ? As far as I can tell, 7.10G3 Quiz just uses read-ahead (& write
behind, which is meaningless). Is 8.30 (due July??) the same ?

If not, could a patch be released ? (ideally back to PH 7.10 or earlier, of
course). Or perhaps select one or other behaviour via a logical, program
parameter, or sitehook.

Setting the new NQL bits would obviously be incompatible with VMS 7.2 &
earlier, and is therefore a non-starter, but setting NLK+RRL which have been
there forever, afaik, would create no compatibility issues.

My Quiz reports presently spend a lot of time in kernel mode, which I can
only put down to locking, and which would therefore be eliminated by this.

Regards,
Chris
_______________________________________________________________________
Chris.Sharman@CCAgroup.co.uk		http://www.ccagroup.co.uk/
CCA Stationery Ltd, Eastway, Fulwood, Preston, Lancashire, PR2 9WS.


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