[OAK-2926] Fast result size estimate

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.0.15, 1.2.3, 1.3.1, 1.4
• Component/s: query
• Labels: performance
• Assignee: Thomas Mueller
• Reporter: Thomas Mueller
• Created: 28/May/15 08:42
• Updated: 08/Oct/19 15:22
• Resolved: 11/Jun/15 07:43

Description

When asking for the correct result size of a query, the complete result needs to be read, so that access rights checks are made, and (unless the index is known to be up-to-date, and can process all conditions) so that the existence and all query conditions are checked.

Jackrabbit 2.x supports a fast way to get an estimate of the result size, without doing access rights checks. See also JCR-3858.

Please note that according to the JCR API, NodeIterator.getSize() may return -1 (for "unknown"), and in Oak this is currently done if counting is slow. This would also need to be disabled if a fast result size estimate is needed.

Issue Links

• relates to: OAK-2730 Faster result count estimation for QueryResult on lines of resultFetchSize support in JR2
• relates to: OAK-2807 Improve getSize performance for "public" content
• relates to: OAK-2914 scalabilty benchmark for queries getSize()
• relates to: OAK-2977 Fast result size estimate: OSGi configuration