Re: Deadlock Question

Hi Tom,

   Without the index on the child table Oracle will have to do a full table scan on the child table. This means acquiring a lock to do it. (BUt that will not be possible if there is a pending transaction against child table.)

   However, if there is an index on the child table, Oracle does not need to do a full table scan but it can read the index without locking the table and locate the corresponding row.

   Is my understanding correct.

   If it is, would the same problem arise if two different transactions are trying to update two different rows in the child table at the same time. I checked that out - they did not block each other (this is without an index on child table). But the block happens while updating parent table (without child table index). Somewhere I am missing some basic thing...     

Ram. Received on Fri Jun 03 2005 - 13:08:36 CDT