On Thu, 28 Apr 2005, Tzahi Fadida wrote: > I am using the /proc/sys/vm/block_dump > to see reading and writing of blocks for a process. > I am looking at the postgresql database process. > When I run a query for the first time I see a lot of > READs. but the next times I run it, it doesn't show > READs, suggesting the kernel have cahced those blocks > somewhere. Even if I get out of the program and reenters > it doesn't help. I also disabled the swapfile just in case(probably not > related). > How can I flush this caching?
1. reboot the machine ;) 2. umount and re-mount the file system whose files you want un-cached (upon umount, all cached pages of the umounted file system are freed by the kernel). 3. modify the kernel's source to avoid caching on a per-filesystem (perhaps add an option to the mount command stating "no cache"?). not sure how easy this is ;) something else about caching (summary: the cache holds both data and meta-data, and it is the later that's more expensive to access): http://www.ussg.iu.edu/hypermail/linux/kernel/0209.0/0929.html -- guy "For world domination - press 1, or dial 0, and please hold, for the creator." -- nob o. dy ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
