ORACLE 8.1.6 Drop table performace

[Guenter Radakovits]

Hi,

Creating a one extent table tries < 1 sec
dropping the same table can try about 2 - 5 minutes some times

any idea?
thak you

[Dave Chamberlin]

Try using the truncate command, which does not generate redo, and is faster than the drop command. It also resets the high water mark in the table

[Guenter Radakovits]

Thank you fo your answer
but we did not have the possibility to change the application

[Steve Slade]

Guenter,

Is there anything else running at the same time, that could be causing contention?

When you drop a table, it is removed from the catalog, along with any associated constraints, indexes - also constraints are checked for Referential Integrity with other tables. That said, it should be pretty quick - at least as quick as a create, as the system does not perform a 'DELETE' in the SQL sense, and generates minimal Redo as a result.

I have read somewhere, that operations of this sort can have contention on the system tablespace, as that is where the catalog is stored, and the code for these operations can only run singularly. Therefore, if multiple create and drop table commands are running at the same time, they will run sequentially, regardless of how many processors your system has.

A way around this is to alter the tablespace you create your tables in, to locally managed - no code changes should be required. I cannot remember the exact command but I think you add the clause 'extent management local autoallocate ' or 'extent management local uniform size ___M' to your usual tablespace commands. The two options are used to contol fragmentation. For more details look at 8.1.X documentation. I canl try and fish out more if it helps.