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### What problem does this PR solve? Issue Number: None Related PR: apache#63389 Problem Summary: New sessions currently use `min_scanners_concurrency = 1`. Raise this default to `4` and update its description so regular scans use a higher concurrency floor under the existing scanner-count, concurrency, and memory limits. Serial scans continue to use one scanner. Expression ZoneMap filtering is already enabled by default on master (`enable_expr_zonemap_filter = true`). ### Release note Increase the default `min_scanners_concurrency` from `1` to `4` for new sessions. ### Check List (For Author) - Test: FE unit tests and Checkstyle passed. - `MAVEN_ARGS='-T 48' bash run-fe-ut.sh --run org.apache.doris.qe.SessionVariablesTest,org.apache.doris.qe.VariableMgrTest`: 31 tests, 0 failures/errors/skips. - `mvn -T 48 checkstyle:check -pl fe-core` (from `fe/`): 0 violations. - `git diff --check`: passed. - Behavior changed: Yes. New sessions default to a minimum scanner concurrency of 4. - Does this need documentation: No. The session-variable description is updated with the new default.
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This was referenced Sep 22, 2026
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What problem does this PR solve?
Issue Number: None
Related PR: #63389
Problem Summary:
New sessions currently use
min_scanners_concurrency = 1. Raise this default to4and update its description so regular scans use a higher concurrency floor under the existing scanner-count, concurrency, and memory limits. Serial scans continue to use one scanner.Expression ZoneMap filtering is already enabled by default on master (
enable_expr_zonemap_filter = true).Release note
Increase the default
min_scanners_concurrencyfrom1to4for new sessions.Check List (For Author)
MAVEN_ARGS='-T 48' bash run-fe-ut.sh --run org.apache.doris.qe.SessionVariablesTest,org.apache.doris.qe.VariableMgrTest: 31 tests, 0 failures/errors/skips.mvn -T 48 checkstyle:check -pl fe-core(fromfe/): 0 violations.git diff --check: passed.