Can anybody tell me in brief what is
HIGH WATER LEVEL & LOW WATER LEVEL in Oracle
Thanks in advance
High water mark if that is waht you mean then.....it refers to block storage..........it is the highest block which had rows in it.......suppose you delete some rows from a table then oracle will still keep the high water mark............however if you truncate a table then the high water mark would be deleted......
if you mean high water level then.............gimme a sec i ma busy.......tryin to fig out what this heck means...
HIGH WATER MARK indicates the level upto which the last table block reached.As soon as u enter data into the table HIGH WATER MARK also rises.When u delete the rows from the table the HIGH WATER MARK remains where it is,it doesnot fall.This leads to more I/O since when Oracle performs scan of the table it scans upto the HIGH WATER MARK.
HIGH WATER MARK is reset only when u truncate or export the table,drop the table and import it again.
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Rohit nirkhe,Oracle DBA,OCP 8i
yes. you are correct.
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