eXist-db 2.2RC2

The second release candidate for eXist 2.2 is available for download.

RC2 contains numerous bug fixes, enhancements and performance improvements. The new range index - introduced with RC1 - has seen a lot of real-world testing and bug fixing to make sure it is properly used by queries, so they benefit from the superior performance of this new index.

Beyond the new range index, a number of other performance bottlenecks have been identified. Each of those can have a huge effect on particular queries: for example, the removal of unnecessary type checks on index-assisted functions and redundant cleanup cycles in the query engine increased performance in some cases by factor 10 or more. NGram indexes have also seen a huge speed up with respect to indexing as well as query times. Finally, the query optimizer missed to descend into some types of expressions, causing them to run without optimization.

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Using the NGram index to search Sanskrit texts

Noteworthy other changes include, but are not limited to:

  • Fix: a caching issue led to random index failures for data sets large enough to fill the entire caching space.
  • Fix: faster addition or insertion of nodes using update extensions. In particular, the time to append a node should not increase with the size of the document anymore.
  • Fix: removing a collection containing a large number of documents or subcollections resulted in a huge recovery log being written, which does not only consume disk space, but may eventually also lead to recovery failures.
  • Enhancement: faster consistency checks and thus backups.
  • Enhancement: allow queries to be terminated by user: now effectively stops all types of expressions that have blocked db shutdown before.
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Query profiling with Monex

Nearly all apps shipping with eXist have been enhanced as well. There were so many changes and additions that we will need to cover them in a separate article during the next days, so please stand by.

The final release of eXist 2.2 is scheduled for the first half of August.