Analyze Table
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Thread: Analyze Table

  1. #1
    Join Date
    May 2001
    Location
    London
    Posts
    149
    Hi,

    I want to know wheather analyze table will analyze all indexes in that table or wheather we have to explicitely analyze indexes.

    Analyze table tbl_name compute statistics;
    or
    Analyze table tbl_name estimate statistics 1000 rows;


    Thanks in advance

    Paresh

  2. #2
    Join Date
    Nov 2000
    Location
    greenwich.ct.us
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    COMPUTE will analyze any indexes on that table.
    Jeff Hunter
    marist89@yahoo.com
    http://marist89.blogspot.com/
    Get Firefox!
    "I pledge to stop eating sharks fin soup and will not do so under any circumstances."

  3. #3
    Join Date
    Sep 2001
    Location
    NJ, USA
    Posts
    1,287
    Both forms:

    Analyze table ... comute statistics;
    and
    Analyze table ... estimate statistics sample 1000 rows;

    will compute / estimate statistics for all indexes on this table.

    1) COMPUTE

    SQL> analyze table train.emps delete statistics;
    Table analyzed.

    SQL> select TABLE_NAME, num_rows, avg_row_len from all_tables where owner ='TRAIN' and table_name='EMPS';
    select index_name, table_name, blevel, leaf_blocks from all_indexes where owner ='TRAIN' and table_name='EMPS';

    TABLE_NAME NUM_ROWS AVG_ROW_LEN
    ------------------------------ ---------- -----------
    EMPS

    SQL>
    INDEX_NAME TABLE_NAME BLEVEL LEAF_BLOCKS
    ------------------------------ ------------------------------ ---------- -----------
    EMPS_PK EMPS
    IDX_DEP_ID_EMP EMPS
    IDX_FIRST_NAME EMPS
    IDX_JOB_ID_EMP EMPS
    IDX_U_LAST_NAME EMPS

    SQL> analyze table train.emps compute statistics;

    Table analyzed.

    SQL> select TABLE_NAME, num_rows, avg_row_len from all_tables where owner ='TRAIN' and table_name='EMPS';

    TABLE_NAME NUM_ROWS AVG_ROW_LEN
    ------------------------------ ---------- -----------
    EMPS 49902 68

    SQL> select index_name, table_name, blevel, leaf_blocks from all_indexes where owner ='TRAIN' and table_name='EMPS';

    INDEX_NAME TABLE_NAME BLEVEL LEAF_BLOCKS
    ------------------------------ ------------------------------ ---------- -----------
    EMPS_PK EMPS 1 190
    IDX_DEP_ID_EMP EMPS 1 44
    IDX_FIRST_NAME EMPS 2 732
    IDX_JOB_ID_EMP EMPS 1 40
    IDX_U_LAST_NAME EMPS 2 356
    2) ESTIMATE SAMPLE
    SQL> analyze table train.emps delete statistics;

    Table analyzed.

    SQL> select TABLE_NAME, num_rows, avg_row_len from all_tables where owner ='TRAIN' and table_name='EMPS';

    TABLE_NAME NUM_ROWS AVG_ROW_LEN
    ------------------------------ ---------- -----------
    EMPS

    SQL> select index_name, table_name, blevel, leaf_blocks from all_indexes where owner ='TRAIN' and table_name='EMPS';

    INDEX_NAME TABLE_NAME BLEVEL LEAF_BLOCKS
    ------------------------------ ------------------------------ ---------- -----------
    EMPS_PK EMPS
    IDX_DEP_ID_EMP EMPS
    IDX_FIRST_NAME EMPS
    IDX_JOB_ID_EMP EMPS
    IDX_U_LAST_NAME EMPS

    SQL> analyze table train.emps estimate statistics sample 1000 rows;
    Table analyzed.

    SQL> select TABLE_NAME, num_rows, avg_row_len from all_tables where owner ='TRAIN' and table_name='EMPS';

    TABLE_NAME NUM_ROWS AVG_ROW_LEN
    ------------------------------ ---------- -----------
    EMPS 49902 68

    SQL> select index_name, table_name, blevel, leaf_blocks from all_indexes where owner ='TRAIN' and table_name='EMPS';

    INDEX_NAME TABLE_NAME BLEVEL LEAF_BLOCKS
    ------------------------------ ------------------------------ ---------- -----------
    EMPS_PK EMPS 1 190
    IDX_DEP_ID_EMP EMPS 1 44
    IDX_FIRST_NAME EMPS 2 735
    IDX_JOB_ID_EMP EMPS 1 40
    IDX_U_LAST_NAME EMPS 2 358




  4. #4
    Join Date
    May 2001
    Location
    London
    Posts
    149
    Thanks a lot

    Paresh

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