[OAK-6710] CommitMitigated merge policy should not reduce performance significantly

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7.7
• Fix Version/s: 1.7.14, 1.8.0
• Component/s: lucene
• Labels: performance scalability
• Epic Link: indexer resilience
• Assignee: Tommaso Teofili
• Reporter: Vikas Saurabh
• Created: 23/Sep/17 09:21
• Updated: 30/Dec/17 09:05
• Resolved: 20/Dec/17 12:01

Description

While running performance tests (internally) using latest unstable releases having CommitMitigatedTieredMergePolicy we observed significant drop in performance (OAK-6704).
The policy, although bad for performance, showed dramatic drop in churn created in data store size. So, clearly, OAK-5192 did what it intended to do.

Opening this issue to factor in drop in performance and then set the default back to CommitMitigatedTieredMergePolicy.

Issue Links

• is related to: OAK-6717 DefaultIndexWriter using incorrect merge scheduler
• is related to: OAK-6718 Configure RAM buffer size used by IndexWriter with oak-run indexing
• relates to: OAK-6704 Set default merge polity to tiered as CommitMitigatingTieredMergePolicy seems to be bad for performance
• relates to: OAK-5192 Reduce Lucene related growth of repository size