Re: [HACKERS] Lock freeze ? in MVCC

From: Vadim Mikheev <vadim(at)krs(dot)ru>
To: Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp>
Cc: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>, pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Lock freeze ? in MVCC
Date: 1999-04-28 11:01:56
Message-ID: 3726EAA4.FAD4541A@krs.ru
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Hiroshi Inoue wrote:
>
> >
> > if we already have some lock with priority X and new requested
> > lock has priority Y, Y <= X, then lock must be granted.
> >
> > Also, I would get rid of lockReadPriority stuff...
> >
>
> I found a problem to get rid of lockReadPriority stuff completely.
> If there's a table which is insert/update/deleted very frequenly by
> several processes,processes which request the high priority lock
> (such as vacuum) could hardly acquire the lock for the table.

I didn't mean to get rid of code checking waiter locks completely.
I just said that condition below

if (!lockReadPriority)

is unuseful any more.

Read my prev letter when, imo, we have to take waiters into
account.

Vadim

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