diffrence between estimate statistics and compute statistics

[dasdeba]

Hi all,

What is the difference between

analyze table compute statistics

and

analyze table estimate statistics ?

What is the default % (60% or 70% or 25% or ? ) in the second
case?

Deba

[abhaysk]

defualt for estimate is 1064 rows as sample if you omit it.

Compute : 100% ( all rows )


RTM

[patel_dil]

Compute : Computes Statistics for whole Table(for all rows).

Estimate: - Computes Statistics on sample of rows over the table.
- Be default, its 1064 rows.
- You can specify rows in numbers or in percentage of total rows.
- If the number or percentage of rows exceeds 50%, Statistics will be computed on all rows in Table.

HTH.

[slimdave]

also, you should be using DBMS_STATS instead of the analyze command.

you can also get the option of sampling by % of rows or by % of blocks.