Re: Can anyone explain exactly what is meant by high water mark?

Hi,

The high water mark is an internal parameter for each table that Oracle uses to determine how much space in the current extent has been used. It is needed because Oracle, like most -- if not all -- data base management systems does not physically remove deleted rows from a table.

Deleting rows from a table does NOT change the high water mark. I believe that there are only two ways to reduce the high water mark of a user table: 1) drop the table and 2) truncate the table.

Truncate works by setting the high water mark back to the beginning of the first extent of the table. This is the reason truncate is such a fast operation and cannot be rollbacked.

Regards

Jerry

xyzer_at_samsung.co.kr wrote:
>
> xyzer_at_samsung.co.kr wrote:
>
>
>
> Hi,
>
> Can anyone explain exactly what is meant by high
> water mark?
> Any good examples?
>
>
> Sungkwan Park
>
> ORACLE + PARADIGM = ORADIGM
>
>
>
> µ¶µµ´Â ¿ì¸® ¶¥ÀÔ´Ï´Ù.
> -¼º°ü
>
>
Received on Sat Feb 21 1998 - 00:00:00 CST