Comments on: fadvise syscall, myisam data file caching, and a lesson learned in debugging http://ebergen.net/wordpress/2009/06/11/fadvise-syscall-myisam-data-file-caching-and-a-lesson-learned-in-debugging/ You will probably want some waders, a pickaxe, and one of those hats with a light on it before you go in here. Fri, 11 May 2012 07:02:34 +0000 hourly 1 http://wordpress.org/?v=3.3.2 By: Eric Wheeler http://ebergen.net/wordpress/2009/06/11/fadvise-syscall-myisam-data-file-caching-and-a-lesson-learned-in-debugging/comment-page-1/#comment-367897 Eric Wheeler Mon, 21 Nov 2011 06:37:00 +0000 http://ebergen.net/wordpress/?p=271#comment-367897 Interesting article, I wonder: do you have a simple binary that opens the .MYD, calls fadvise on the read-only fd, and daemonizes, and would this be sufficient to get the kernel to hold the file content cached? Can you or have you released your cache-pinning program? I'm looking to use fadvise for an opposite example: I need to set FADV_NOREUSE for block-device backups since it is pointless to cache a sequential block-device read when it will only be read once. In this case, I am using the rdiff to replicate LVM snapshots, and was thinking of writing an LD_PRELOAD wrapper for open() and fadvising the resulting file descriptor instead of hacking the rdiff code. Since you have dug into the depths of fadvise, do you you have any advice here? -Eric Interesting article, I wonder: do you have a simple binary that opens the .MYD, calls fadvise on the read-only fd, and daemonizes, and would this be sufficient to get the kernel to hold the file content cached? Can you or have you released your cache-pinning program?

I’m looking to use fadvise for an opposite example: I need to set FADV_NOREUSE for block-device backups since it is pointless to cache a sequential block-device read when it will only be read once.

In this case, I am using the rdiff to replicate LVM snapshots, and was thinking of writing an LD_PRELOAD wrapper for open() and fadvising the resulting file descriptor instead of hacking the rdiff code.

Since you have dug into the depths of fadvise, do you you have any advice here?

-Eric

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