Skip site navigation (1) Skip section navigation (2)

Re: seq scan cache vs. index cache smackdown

From: Ron Mayer <rm_pg(at)cheapcomplexdevices(dot)com>
To: Merlin Moncure <merlin(dot)moncure(at)rcsonline(dot)com>
Subject: Re: seq scan cache vs. index cache smackdown
Date: 2005-02-22 01:14:19
Message-ID: 421A876B.6010308@cheapcomplexdevices.com (view raw or flat)
Thread:
Lists: pgsql-performance
Merlin Moncure wrote:
> 
> readv and writev are in the single unix spec...and yes ...
> 
> On some systems they might just be implemented as a loop inside the
> library, or even as a macro.

You sure?

Requirements like this:
  http://www.opengroup.org/onlinepubs/007908799/xsh/write.html
  "Write requests of {PIPE_BUF} bytes or less will not be
   interleaved with data from other processes doing writes
   on the same pipe."
make me think that it couldn't be just a macro; and if it
were a loop in the library it seems it'd still have to
make sure it's done with a single write system call.

(yeah, I know that requirement is just for pipes; and I
suppose they could write a loop for normal files and a
different special case for pipes; but I'd be surprised).

In response to

pgsql-performance by date

Next:From: amritDate: 2005-02-22 05:00:58
Subject: Re: Problem with 7.4.5 and webmin 1.8 in grant function
Previous:From: Mark KirkwoodDate: 2005-02-21 21:51:16
Subject: Re: Problem with 7.4.5 and webmin 1.8 in grant function

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group