[OAK-7390] QueryResult.getSize() can be slow for many "or" or "union" conditions

• Type: Improvement
• Status: Reopened
• Priority: Major
• Resolution: Unresolved
• Component/s: query
• Epic Link: indexer resilience
• Assignee: Thomas Mueller
• Reporter: Thomas Mueller
• Created: 05/Apr/18 09:09
• Updated: 26/May/21 14:53

Description

For queries with many union conditions, the "fast" getSize method can actually be slower than iterating over the result.

The reason is, the number of index calls grows exponential with regards to number of subqueries: (3x + x^2) / 2, where x is the number of subqueries. For this to have a measurable affect, the number of subqueries needs to be large (more than 100), and the index needs to be slow.