DML,Transactions and index updates
Hi,
Its known adding indexes slows down the DML on the table. i.e. every time table data changes, the index has to be recalculated. What i am trying to understand is whether the index is recalculated as soon as oracle sees the change?
To elaborate, lets say i have a table abc with 4 columns, column1, column2, column3 and column4. I have two indexes; one unique on column1 and another non unique index on column2.
So when i am trying to update column4, which is not indexed, will there be any transactional data generated for this operation? Will it be generated if i am updating column2 ( with non-unique index) ?
What i am interested to know is how transactions boundaries impact the calculation of index. Will oracle always generate transactional entries and recalculate affected indexes even before the transaction is committed and the data change is made permanent ?