morrySnow commented on code in PR #64793:
URL: https://github.com/apache/doris/pull/64793#discussion_r3479088724
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fe/fe-core/src/main/java/org/apache/doris/qe/SessionVariable.java:
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@@ -1636,6 +1640,27 @@ public enum IgnoreSplitType {
"Whether to force to local shuffle on pipelineX
engine."})
private boolean forceToLocalShuffle = false;
+ @VarAttrDef.VarAttr(
+ name = LOCAL_SHUFFLE_BUCKET_UPGRADE_RATIO, fuzzy = false, varType
= VariableAnnotation.EXPERIMENTAL,
+ description = {"FE规划Local Shuffle时, 当池化bucket
join所在fragment的每BE实例数大于"
+ + "每BE有数据分桶数的该倍数时, 将join两侧的桶分布本地重分发为hash分布以突破桶数并发上限。"
+ + "必须大于1才生效; 小于等于1(含0和负数)时关闭该优化",
+ "When FE plans local shuffle and a pooled bucket join
fragment has more instances"
+ + " per BE than (buckets-with-data per BE) * this ratio,
re-distribute both join"
+ + " sides with local hash instead of bucket hash so join
parallelism is no longer"
+ + " capped at bucket count. Only takes effect when > 1;
values <= 1 (including 0"
+ + " and negatives) disable the upgrade."}, needForward =
true)
+ private double localShuffleBucketUpgradeRatio = 1.5;
Review Comment:
🟡 **Default value discrepancy with PR description**: The code defaults to
`1.5`, but the PR description says "Add session variable
`local_shuffle_bucket_upgrade_ratio` (default 1.0, <= 1 disables)". A default
of `1.5` means the upgrade fires when `min(instances, cores) > min(buckets,
cores) * 1.5`, while a default of `1.0` would disable it entirely (since `ratio
<= 1` disables). This is a significant behavioral difference — please reconcile
the code and the PR description.
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