[OAK-3889] SegmentMk StringCache memory leak

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.3.15, 1.4
• Component/s: segmentmk
• Assignee: Alex Deparvu
• Reporter: Alex Deparvu
• Created: 18/Jan/16 09:49
• Updated: 08/Oct/19 15:22
• Resolved: 25/Jan/16 13:33

Description

The StringCache is made of 2 components: a FastCache and a Lirs Cache and both caches use the same key object 'StringCacheEntry' with the condition that the FastCache contains the string value itself with the key while the Lirs Cache will only contain the msb, lsb and offset.
Sharing the same key leads to issues when a value qualifies for both caches as it results in the string value ending up contained in the Lirs Cache, effectively blowing up the cache's size. [0]
On a test I ran I noticed the Lirs Cache going up to 800mb even though it was configured at 256mb.

[0] https://github.com/apache/jackrabbit-oak/blob/trunk/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/segment/StringCache.java#L86

Issue Links

• relates to: OAK-3007 SegmentStore cache does not take "string" map into account