The High Water Mark in a table is the highest point at which data has ever
been in that table. Simply deleting records from the table does not effect
it. The only way to reset it is to truncate the table. A table growing
dynamically doesn't affect it directly, only when data is inserted and the
HWM always moves in 5 block increments. It is used in a full-table-scan
when Oracle sees the HWM it knows it does not need to read any more blocks
from the table because data has never been higher. It is also used by
SQL*LOADER for direct path loads and by Oracle for direct path inserts.
Hope this helps clear it up.
Kenny Gump
OCP 7.3 DBA
amerar_at_theocc.com wrote in message <782hph$bb7$1_at_nnrp1.dejanews.com>...
>
>
>Hello,
>
>I am a bit confused about what the high water mark is and what its effects
>are. I'm confused about what happens to the HWM when you delete records
from
>a table and also when a table grows.
>
>Any help is appreciated.
>
>Please send comments to my e-mail.
>
>Thank you,
>
>Arthur
>amerar_at_theocc.com
>
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Received on Tue Jan 19 1999 - 15:38:03 CST
