Question: We have an update statement that has
switched from a full-table scan to an "inlist iterator.
Here is the "good" explain plan:
You see ACCESS FULL of the table FACTURA.
But this EXPLAIN PLAN has changed automatically, as we made
no manual action:
How do we return this SQL to perform the full-table scan
using the FULL hint?
change was likely caused by automatic CBO statistics
re-analysis, but you can "lock-down" a full-table scan by
using the "FULL" hint. Here is an example if the FULL
select /*+ full parallel(emp,35)*/
Using the FULL hint with
the PARALLEL hint
When using parallel
query, one should seldom turn on parallelism at the
table level, alter table customer parallel 35, because
the setting of parallelism for a table influences the
optimizer. This causes the optimizer to see that the
full-table scan is inexpensive. Hence, most Oracle
professionals specify parallel query on a query-by-query
basis, combining the full hint with the parallel hint to
ensure a fast parallel full-table scan.