In some cases, when the user executes the query for the first time, an error of the exceeded mem limit will be reported, and the query will be successful only after the second execution.
This is because when the query is executed for the first time, the memory consumed by adding the page cache and other caches is recorded in the query mem tracker, hoping to unify the behavior of multiple queries.
A temporary solution, remove the hook of scanner thread, test clickbench q13
Before removing the scanner thread hook
Enable page cache: 3G for the first query, 3G for the tracker; 900M for the second query, 900M for the tracker.
Turn off page cache: 1.9G for the first query, 1.9G for the tracker; 900M for the second query, 900M for the tracker
After removing the scanner thread hook and fix MemTrackerLimiter::cache_consume_local bug
Enable page cache: 2916M for the first query, 1147M for the tracker; 979M for the second query, 1144M for the tracker
Turn off page cache: 1809M for the first query, 1147M for the tracker; 975M for the second query, 1145M for the tracker
TODO, a better solution is to track storage-related memory separately, in the scanner thread. Otherwise, it is impossible to know where the process memory grows when querying.
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