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    SubjectRe: Very High Load, kernel 2.4.18, apache/mysql
    The big question is - why that much CPU usage?

    Possible answers:
    * PHP, mySQL, Apache - needs that amount of CPU to perform the requested
    (you have got suggestions from others)

    * The implementation if either has bugs that cause the CPU usage. Garbage
    collection? Ineffective algorithms?
    - Not much to do other than collecting execution profiles, quite advanced -
    recompiling of the tools will probably be needed... And probably help from
    the tools developers...

    * The implementation of the user code has bugs that cause the CPU usage.
    One example:
    SQL SELECT with unindexed data - this can usually be noticed as buffer in load
    in vmstat but since all data fits in memory - it would cause scans in memory,
    with lots of RAM cache misses... And it would work well as long as the
    scanned data was smaller than the CPU cache?
    - Suggestion: Review your index keys and select statements to make sure that
    they match!

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      Last update: 2005-03-22 13:29    [W:0.023 / U:1.032 seconds]
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