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Created October 26, 2021 18:35
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apache-hbase-2.4.7-releasenotes.md

HBASE 2.4.7 Release Notes

These release notes cover new developer and user-facing incompatibilities, important issues, features, and major improvements.

  • HBASE-26274 | Major | Create an option to reintroduce BlockCache to mapreduce job

Introduce `hfile.onheap.block.cache.fixed.size` and default to disable. When using ClientSideRegionScanner, it will be enabled with a fixed size for caching INDEX/LEAF_INDEX block when a client, e.g. snapshot scanner, scans the entire HFile and does not need to seek/reseek to index block multiple times.

  • HBASE-26270 | Minor | Provide getConfiguration method for Region and Store interface

Provide 'getReadOnlyConfiguration' method for Store and Region interface

  • HBASE-26273 | Major | TableSnapshotInputFormat/TableSnapshotInputFormatImpl should use ReadType.STREAM for scanning HFiles

HBase's MapReduce API which can operate over HBase snapshots will now default to using ReadType.STREAM instead of ReadType.DEFAULT (which is PREAD) as a result of this change. HBase developers expect that STREAM will perform significantly better for average Snapshot-based batch jobs. Users can restore the previous functionality (using PREAD) by updating their code to explicitly set a value of `ReadType.PREAD` on the `Scan` object they provide to TableSnapshotInputFormat, or by setting the configuration property "hbase.TableSnapshotInputFormat.scanner.readtype" to "PREAD" in hbase-site.xml.

  • HBASE-26276 | Major | Allow HashTable/SyncTable to perform rawScan when comparing cells

Added --rawScan option to HashTable job, which allows HashTable/SyncTable to perform raw scans. If this property is omitted, it defaults to false. When used together with --versions set to a high value, SyncTable will fabricate delete markers to all old versions still hanging (not cleaned yet by major compaction), avoiding the inconsistencies reported in HBASE-21596.

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