[LUCENE-9002] query caching leads to absurdly slow queries

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 7.7.2, 8.2
• Component/s: core/search
• Labels: cache performance
• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Guoqiang Jiang
• Created: 09/Oct/19 04:34
• Updated: 28/Aug/22 15:51

Description

Description
We have dozens of ES clusters(based on Lucene) for metric scenarios. Most of the queries are like this: host_ip:10.10.10.10 AND timestamp:[2019-10-01 00:00:00 TO 2019-10-05 23:59:59]. And we frequently encounter some absurdly slow queries.

Solution
For a long time range query(e.g. 5 days), each range query will consume tens of megabytes of memory and spend hundreds of milliseconds to cache, but the benefits are not obvious. And those large cache entries will cause frequent cache eviction. So it's better to skip the caching action directly when large range query appears with a selective lead iterator.

Issue Links

• relates to: LUCENE-8027 Do not cache clauses if they might make the query more than X times slower
• relates to: LUCENE-8213 Cache costly subqueries asynchronously
• links to: GitHub Pull Request #940