Query cache improvements
Details
| Detail name | Value |
|---|---|
| Changelog Number | 10148 |
| Type | Improvement |
| Status | Resolved |
| Fix Versions | Exasol 7.0.7, Exasol 6.2.14 |
| Resolution Date | 2021-02-12 |
Background
The purpose of query cache is to provide a caching mechanism for result sets of frequent queries. This performance improvement comes with a certain overhead, however.
In scenarios with very frequent (tiny) query executions, this overhead may become significant and deteriorate over time, slowing down overall database performance.
In such cases, disabling the query cache on the system level will remove the overhead.
Improvement
Internal process in the query cache has been improved to significantly reduce this overhead and impact on system usability in the above-mentioned scenario:
- speed-up query cache garbage collection
- reduction of dependencies between query cache and transaction service
- no more caching of very cheap queries
