[CASSANDRA-9096] Improve ByteBuffer compression interface

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 2.2.0 rc1
• Labels: qa-resolved
• Assignee: Branimir Lambov
• Reporter: Branimir Lambov

Authors

Branimir Lambov

Reviewers

Joshua McKenzie

• Tester: Alan Boudreault
• Created: 02/Apr/15 10:00
• Updated: 16/Apr/19 09:31
• Resolved: 26/May/15 15:24

Description

Now that we have a few uses of compression/decompression on ByteBuffers it is time to finalize the interface before it becomes set in stone with 2.2. The current code has some shortcomings:

• The interface uses the buffers' positions and limits instead of accepting offset and length as parameters. This necessitates that the buffers be duplicated before they can be compressed for thread-safety, something that adds burden to the caller, is prone to being forgotten, and we could generally do without for performance.
• The direct/non-direct buffer support needs to be more clearly defined. The current useDirectOutputByteBuffers is not named well.
• If we don't want to support non-direct buffers everywhere as a fallback, we should clearly state the decision and rationale.
• How should WrappedByteBuffer treat direct/indirect buffers?
• More testing is necessary as e.g. errors in DeflateCompressor were only caught in CASSANDRA-6809.

Issue Links

• relates to: CASSANDRA-8464 Support direct buffer decompression for reads
• relates to: CASSANDRA-8709 Convert SequentialWriter from using RandomAccessFile to nio channel
• relates to: CASSANDRA-6809 Compressed Commit Log