[OAK-4112] Replace the query exclusive lock with a cache tracker

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.4.6, 1.5.2, 1.6.0
• Component/s: documentmk, mongomk
• Labels: performance
• Flags: Patch
• Assignee: Tomek Rękawek
• Reporter: Tomek Rękawek
• Created: 09/Mar/16 11:06
• Updated: 20/Dec/17 09:36
• Resolved: 28/Apr/16 10:03

Description

The MongoDocumentStore#query() method uses an expensive TreeLock#acquireExclusive method, introduced in OAK-1897 to avoid caching outdated documents.

It should be possible to avoid acquiring the exclusive lock, by tracking the cache changes that occurs during the Mongo find() operation. When the find() is done, we can update the cache with the received documents if they haven't been invalidated in the meantime.

Issue Links

• blocks: OAK-4320 Use the cache tracker in the RDB Document Store
• is related to: OAK-4408 RDBDocumentStore: synchronize access to BloomFilter
• is related to: OAK-6347 Don't track local changes in the document cache tracker
• is related to: OAK-4411 DocumentNodeStore: Improve test coverage for concurrent updates and queries
• is required by: OAK-4168 Replace the massive lock acquire with cache tracker in bulk createOrUpdate()