When SPARQL queries are run on the Nativestore with assertions enabled (with -ea VM flag), performance keeps degrading over time. Simple queries with single pattern to match, have consistent query performance, but when the query complexity increases, this behavior is observed.
A bug was introduced in the BTree while working on SES-776. BTree iterators no longer deregistered themselves with the root node upon closing, causing the list of listeners for this node to grow indefinately. An assertion checked for presence of listeners with List.contains(...), which caused the performance degradation. But even with assertion disabled, this is a serious issue for long running or intensively used native stores.
Bug
Resolved
Critical
Query performance degradation with assertions enabled