Re: O_DIRECT question

From: Bill Davidsen
Date: Fri Jan 26 2007 - 10:55:49 EST


Denis Vlasenko wrote:

Well, I too currently work with Oracle.
Apparently people who wrote damn thing have very, eh, Oracle-centric
world-view. "We want direct writes to the disk. Period." Why? Does it
makes sense? Are there better ways? - nothing. They think they know better.

I fear you are taking the Windows approach, that the computer is there to serve the o/s and applications have to do things the way the o/s wants. As opposed to the UNIX way, where you can either be clever or stupid, the o/s is there to allow you to use the hardware, not be your mother.

Currently applications have the option of letting the o/s make decisions via open/read/write, or let the o/s make decisions and tell the application via aio, or using O_DIRECT and having full control over the process. And that's exactly as it should be. It's not up to the o/s to be mother.

(And let's not even start on why oracle ignores SIGTERM. Apparently Unix
rules aren't for them. They're too big to play by rules.)

Any process can ignore SIGTERM, or do a significant amount of cleanup before exit()ing. Complex operations need to be completed or unwound. Why select Oracle? Other applications may also do that, with more or less valid reasons.

--
Bill Davidsen <davidsen@xxxxxxx>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot

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