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RE: db_file_multiblock_read_count causing full scans to takelonger?

From: Kevin Lidh <kevin.lidh_at_gmail.com>
Date: Tue, 19 Dec 2006 14:22:10 -0700
Message-Id: <1166563331.7355.34.camel@lidhfed.lidh.com>


In my case, it's filesystem. Is there a parameter that determines read-aheads? I'll look for HP-UX but if you know of a Linux or other OS parameter, it would make it easier for me to frame the question. As a result of this discussion I re-ran the "time dd" tests and found that the elbow is right before "bs=256k". Even "bs=255k" is faster (and as fast as 128, 32, anything less than 256).

On Tue, 2006-12-19 at 13:03 -0800, Kevin Closson wrote:
> Is this direct I/O or a filesystem? Could the filesystem
> be firing off some uneccessary read-aheads when you do large
> dfmbrc but not when you are nibbling with smaller multiblock request?
>

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Received on Tue Dec 19 2006 - 15:22:10 CST

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