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  1. #1
    Join Date
    Oct 2004
    Posts
    14

    Unanswered: Sybase Performance Benchmarking

    Hi all,

    I have some slow performing stored procs in my database that i need to improve. Before I actually start to change the procs, I need to benchmark the execution times of these procedures. Therefore i want to run the procs a few times and take the average execution time.

    But here lies the problem: after running a procedure the first time, a lot of the data it needs is cached. How do i clear out the data cache (not too worried about the procedure cache), so that all of my run times are worst-case scenarios with as much physical I/O as possible?

    I guess I could run a query such as select * from a massive table to fill the cache with junk, however a query like this takes time to run, and i want to do a lot of benchmarking.

    Any suggestions would be much appreciated.
    thanks!

  2. #2
    Join Date
    Oct 2004
    Posts
    14

    sa_flush_cache()

    ...i've managed to find details of a command:
    Code:
    sa_flush_cache()
    that can be used in Sybase SQL Anywhere. I'm using ASE 12.5.x, is there an equivalent command?

  3. #3
    Join Date
    Sep 2004
    Location
    Stockholm, Sweden
    Posts
    28
    Just a note, if you run a select * from a massive table, the optimizer will use the MRU policy, and the cache will only change it content after the wash mark. A better way would be to dummy update lots of tuples or as you wrote, use the sa_flush_cache()

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