[OAK-3112] Performance degradation of UnsavedModifications on MapDB

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0.7, 1.0.8, 1.0.9, 1.0.10, 1.0.11, 1.0.12, 1.0.13, 1.0.14, 1.0.15, 1.0.16, 1.0.17
• Fix Version/s: 1.0.18
• Component/s: core, mongomk
• Labels: performance
• Assignee: Marcel Reutegger
• Reporter: Marcel Reutegger
• Created: 16/Jul/15 08:30
• Updated: 03/Aug/15 09:38
• Resolved: 21/Jul/15 10:27

Description

UnsavedModifications performance degrades when used in combination with the MapDB backed MapFactory. Calls become more and more expensive the longer the instance is in use. The is caused by a limitation of MapDB, which does not remove empty BTree nodes.

A test performed with random paths added to the map and later removed again in a loop shows a increase to roughly 1 second to read keys present in the map when the underlying data file is about 50MB in size.

Issue Links

• is related to: OAK-3126 Enable HybridMapFactory by default
• relates to: OAK-1768 DocumentNodeBuilder.setChildNode() runs OOM with large tree
• relates to: OAK-2131 Reduce usage of _lastRev