Bloom Filter optimization is added to classical hash join algorithms for Release 17.10. A Bloom Filter is a compact metadata structure on the join column of one relation of a hash join step. The Bloom Filter is used while reading the other relation of the join as an existence check or test. Specifically, the build side of a classical hash join produces a bitmap spool based on the join column while building the hash table. This bitmap spool is passed down to the probe side of the join to be able to filter rows while the probe side is being read.
This feature can improve the performance of some joins.
Bloom Filter is enabled by default.