It depends upon the nature of the typical read lock. If that read lock is
being coordinated with other things that might cause it to be locked
significantly longer than it would take to copy things out, perhaps it could
be worth it.

I think the mechanism for doing read locks ought to be enhanced to tell
whether it is a coordinated lock or not so that this copy-out optimization
would only do so when the read lock was potentially long.

FWIW,
Jason Wharton
www.ibobjects.com


-----Original Message-----
From: Firebird-Architect@yahoogroups.com
[mailto:Firebird-Architect@yahoogroups.com] On Behalf Of Dimitry Sibiryakov
Sent: Tuesday, November 5, 2013 1:24 PM
To: Firebird-Architect@yahoogroups.com
Subject: [Firebird-Architect] PR and EX locks compatibility


Hello, All.

Just a thought: currently if a page in shared cache is locked for
reading, a writer is
standing in queue and waiting. What if page manager instead of that create a
copy of the
page and while it is still read by someone, writer will get the lock
successfully. Can
this make the Bird faster under load?

--
WBR, SD.


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