Re: exp: why have statistics=estimate option?

Chuck Hamilton wrote:
>
> Maybe this is a dumb question, but why even have the
> 'statistics=estimate' option in the export utility? When a table gets
> imported, the _exact_ number of rows imported is already available.
> Why not just use that number to populate DBA_TABLES.NUM_ROWS instead
> of going through the time consuming process of issuing an ANALYZE
> TABLE command?

  ANALYZE can help you to populate the statistics information into DBA_TABLES, DBA_INDEXES, DBA_TAB_COLUMNS, INDEX_STAT, INDEX_HISTOGRAMS. By using these statistics, you can carry out cost-based optimization in the execution of a DML if OPTIMIZER_GOAL is set to CHOOSE, ALL_ROWS or FIRST_ROWS.

---
Name   : Lun Wing San
Title  : Oracle Application Developer of Hong Kong Productivity Council
         Oracle Database Administrator and System Administrator of QRC
Phone  : (852)27885841