Table rebuild should be done after removing most of its data?
orausernOct 23 2012 — edited Oct 24 2012Hi All,
We are on Oracle 10.2.0.4 on Solaris 10. There is a table in my production db that has 872944 number of rows. Most of its data is now unnecessary, we need to retain, based on a date column in the table just last one month's data and delete rest of the data. So after that the table will have just 3000 rows.
However as the table was huge earlier(872k rows prior to delete) , does the delete of data release its oracle blocks and does the size of the table reduce? If not, will it help to rebuild the table online (online redefinition) so that the query that does a full scan on this table goes faster?
I checked using an example table that just delete of data does not remove the oracle blocks - they remain in the user_tables for that table and cost of full table scan remains same. We have a query that does the full table scan so I am thinking that after this delete I should do an online table re-definition , is that the right decision?
Thanks