Behavioral changes denote a marked change in behavior from the previously released
version to this version of Apache Impala.
- Summary:
- Skips scheduling runtime filters for PK-FK joins when the build scan
has no predicate filter, the join is a full table scan, and the bloom filter has a high false
positive probability.
- Previous behavior:
- Runtime filters were scheduled for all PK-FK joins, regardless of
effectiveness.
- New behavior:
- Filters are skipped for PK-FK joins when the build scan is a full
table scan without filters, and the bloom filter has a high false positive probability,
improving performance. For more details see, Skip Scheduling Bloom Filter
Apache
Jira:
IMPALA-12357
- Summary:
- Skips LZ4 compression when sending row batches within the same process
to improve efficiency.
- Previous behavior:
- Row batches were serialized, compressed, sent through KRPC, and then
decompressed, even when the sender and receiver were in the same process.
- New behavior:
- LZ4 compression is skipped for row batches sent within the same
process, reducing unnecessary work and improving performance.
Apache Jira:
IMPALA-12430
