[HBASE-23107] Avoid temp byte array creation when doing cacheDataOnWrite

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0-alpha-1, 2.3.0
• Component/s: BlockCache, HFile
• Labels: gc
• Hadoop Flags: Reviewed
• Assignee: chenxu
• Reporter: chenxu
• Created: 02/Oct/19 01:45
• Updated: 18/Oct/19 00:34
• Resolved: 17/Oct/19 01:54

Description

code in HFileBlock.Writer.cloneUncompressedBufferWithHeader

ByteBuffer cloneUncompressedBufferWithHeader() {
  expectState(State.BLOCK_READY);
  byte[] uncompressedBlockBytesWithHeader = baosInMemory.toByteArray();
  …
}

When cacheOnWrite feature enabled, a temp byte array was created in order to copy block’s data, we can avoid this by use of ByteBuffAllocator. This can improve GC performance in write heavy scenarios.

Issue Links

• links to: GitHub Pull Request #678