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Thread: caching large tables -- 8GB Memory

  1. #1
    Join Date
    Aug 2000
    Location
    NJ
    Posts
    54

    Unhappy

    Hi,
    I am migrating an 8.0.5 databse on NT to 64 bit 8.1.7 databse on AIX 4.3.3 . This IBM Server has 8GB of memory expandable to 16GB.
    The aim is to cache i/o intense data in memory.
    Is it a good idea to cache tables of size 500MB, 1GB in SGA.?
    How is cache handled internally ? What's the syntax for caching a table. My my understanind id that caching has to be specified at table create time.
    Is there any way to cache an already created table ?
    Is there also any way to uncache an already cached table ??
    Please help


    Thanks,
    Geo

  2. #2
    Join Date
    Nov 2000
    Location
    greenwich.ct.us
    Posts
    9,092
    Can you do it? Sure, check out [url]http://technet.oracle.com/docs/products/oracle8i/doc_library/817_doc/appdev.817/a76940/adl07md4.htm#117507[/url]

    Should you do it? That depends on the application. Is all the data going to be needed all the time in cache? I would be inclined to have a large buffer cache instead of caching a whole table.
    Jeff Hunter

  3. #3
    Join Date
    May 2000
    Location
    ATLANTA, GA, USA
    Posts
    3,135
    It is a good idea to cache I/O intensive table/Index data in to SGA.
    There are 3 different cache areas: 1 KEEP, 2 RECYCLE 3 DEFAULT CACHE.

    The DEFAULT is default for all tables and indexes.
    Use KEEP for look up tables (master).
    Use RECYCLE for rarely updated tables
    Use CACHE for all other tables.
    Example:
    alter table customer storage ( buffer_pool keep );



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