demonstrated how bad HWM would be for FTS
I asked to demonstrate what would affect performance if I have a high number of high water mark. Anyway, below is what I have in mind, but I need to get some inputs/advises.
1. let's say I have a table with 100k of rows.
2. delete the data
3. DBA_SEGMENTS is unchanges in bytes which is obvious.
how can I capture the time of the query and show that HWM would take a lot more time to scan the entire table up to the HWM even there is no records.
thanks
Re: demonstrated how bad HWM would be for FTS
Quote:
Originally posted by learning_bee
I asked to demonstrate what would affect performance if I have a high number of high water mark. Anyway, below is what I have in mind, but I need to get some inputs/advises.
1. let's say I have a table with 100k of rows.
2. delete the data
3. DBA_SEGMENTS is unchanges in bytes which is obvious.
how can I capture the time of the query and show that HWM would take a lot more time to scan the entire table up to the HWM even there is no records.
thanks
set timing on
create big table
select count(*) from big table
delete from big table
select count(*) from big table
truncate big table
select count(*) from big table
...compare the timing results