Re: Proposal of tunable fix for scalability of 8.4

Scott Carey escribió:

> Your description (much of which I cut out) is exactly how I understood
> it until Simon Riggs' post which changed my view and understanding.
> Under that situation, waking all shared will leave all XXXXX at the
> front and hence alternate shared/exclusive/shared/exclusive as long as
> both types are contending.  Simon's post changed my view.  Below is
> some cut/paste from it:

Simon's explanation, however, is at odds with the code.

http://git.postgresql.org/?p=postgresql.git;a=blob;f=src/backend/storage/lmgr/lwlock.c

There is "queue jumping" in the regular (heavyweight) lock manager, but
that's a pretty different body of code.

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Alvaro Herrera                                http://www.CommandPrompt.com/
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