Re: [logs] perl question relating to log analysis

From: James F.Hranicky (jfhat_private)
Date: Thu Aug 29 2002 - 20:22:05 PDT

  • Next message: Kohlenberg, Toby: "RE: [logs] what to log/what to look for: stateful log analysis?"

    On Thu, 29 Aug 2002 14:29:46 -0500
    "Andy_Bachat_private" <Andy_Bachat_private> wrote:
    
    > I've done a lot of log-munging in Perl, and I must report that for any
    > significant amount of logs, regexps just aren't fast enough. In some cases
    > I've found a solution using index() and rindex() that was adequate. But 
    > once
    > you get to that level of optimisation, Perl becomes as ugly as C, and the 
    > C
    > solution is generally more flexible (because it doesn't have to be
    > hand-optimised to death to achieve acceptable speed).
    
    Honesty, when I wrote logstats, I found the build-a-subroutine-with-
    regexps-using-eval method to increase performance by about a factor of
    10. 
    
    Just today, my logstats report checked 460,000 lines of log against
    2300 regular expressions (not particularly optimized) in under two hours. 
    This on a 270MHz Ultra 5 with external SCSI and 64M (really!) of RAM. 
    The report itself came in at about 160K bytes, making for a decent summary 
    of 460K lines.
    
    I'm looking forward to upgrading our loghost to a 1.1GHz FBSD box :->
    
    Jim
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