Parallel query on a nonpartitioned index-organized table uses parallel fast full scan. The DOP is determined, in decreasing order of priority, by:
A PARALLEL
hint (if present)
An ALTER
SESSION
FORCE
PARALLEL
QUERY
statement
The parallel degree associated with the table, if the parallel degree is specified in the CREATE
TABLE
or ALTER
TABLE
statement
Work is allocated by dividing the index segment into a sufficiently large number of block ranges and then assigning the block ranges to parallel execution servers in a demand-driven manner. The overflow blocks corresponding to any row are accessed in a demand-driven manner only by the process, which owns that row.