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  1. #1
    Join Date
    Aug 2004

    Unanswered: load in MDC tables.

    UDB ESE (not DPF)v8 fp6a
    AIX 5.2

    I am trying to convert a table to Multi Dimensional Clustering..I created new table with MDC option on 32k pagesize tablespace and tried to load data (3 million records)from the old table which is in tablespace of 4k pagesize..It constantly gave me utility_heap errors and finall stopped after I increased it to 124000 (4K pages) But the load is veryslow..loading only 5000 rows in 25 mins.

    In documentation, it says have utility_heap_sz as large as possible..on a 32bit where database shared memory is limited , how much can we increase this to satisfy it's need? Also, it was mentioned to increase logbufsz..can any one tell me how to tune these? what's the recommended value for logbufsz?

  2. #2
    Join Date
    Aug 2004
    London, UK

    Database shared memory limit on 32-bit AIX

    Theoretical limit is 1.75Gb (providing you're not using fenced processes (-256Mb) and/or intra-parallelism(-256Mb). Remember that bufferpools and sortheap also use the database shared memory. i.e. if you increase util_heap_sz then you'll need to reduce those two.

    The log buffer size is a bit more difficult to determine. The more rows that you insert the larger it should be. If logbufsz is set to 8, say then that means that 32K's worth of rows can be inserted before they need to be written to disk. So your log buffer should ideally be large enough to be able to write data to disk quicker than it's received.

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