Chained Rows
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Thread: Chained Rows

  1. #1
    Join Date
    Feb 2001
    Posts
    23
    I have a table with structure

    A NUMBER Primary Key
    B VARCHAR2(30)
    C NUMBER
    D LONG

    The storage parameters are default, with pctfree & pctused as 10 & 40

    I have 42% of rows as chained rows.. Also I have a Primary Key and another index based on column C

    IF I have to change the storage parameters, how much should I make the values for pctfree and pctused.. ?

    And what is the procedure for solving this permannetly, in Oracle 8i

    Thanks,

    VG

  2. #2
    Join Date
    Sep 2001
    Location
    NJ, USA
    Posts
    1,287
    What value has db block size?
    In mi gess u have migrating (not chained) rows, because
    average row size (with long field) more then db blocksixe - header - pct_free /100 * db_block_size.

    This is not big problem for this table.
    If u going to decrease % of rows as chained rows u have to
    recreate database. 8i doesn't support tablespaces with
    different block sizes.


  3. #3
    Join Date
    Dec 2000
    Location
    Ljubljana, Slovenia
    Posts
    4,439
    Originally posted by Shestakov
    In mi gess u have migrating (not chained) rows, because
    average row size (with long field) more then db blocksixe - header - pct_free /100 * db_block_size.
    Well, if this is the case, then he has chained, not migrated rows, no?. Chained rows are those that can't fit into an empty block because of their size, so their contents is written in two or more blocks (like a chain). On the other hand, migrated rows are those rows which were moved from one block to another because of the update that made them too big to fit into the available free space in the original block, so their entire contents is migrated into another block while the original block contains onl ythe pointer to the new block.
    Jurij Modic
    ASCII a stupid question, get a stupid ANSI
    24 hours in a day .... 24 beer in a case .... coincidence?

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