[CASSANDRA-3427] CompressionMetadata is not shared across threads, we create a new one for each read

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 1.0.2
• Labels: compression
• Severity: Normal
• Assignee: Sylvain Lebresne Assign to me
• Reporter: Sylvain Lebresne

Authors

Sylvain Lebresne

Reviewers

Pavel Yaskevich

• Created: 31/Oct/11 13:57
• Updated: 16/Apr/19 09:32
• Resolved: 31/Oct/11 15:44

Description

The CompressionMetada holds the compressed block offsets in memory. Without being absolutely huge, this is still of non-negligible size as soon as you have a bit of data in the DB. Reallocating this for each read is a very bad idea.

Note that this only affect range queries, since "normal" queries uses CompressedSegmentedFile that does reuse a unique CompressionMetadata instance.

( Background: http://thread.gmane.org/gmane.comp.db.cassandra.user/21362 )