englefly commented on code in PR #66898:
URL: https://github.com/apache/doris/pull/66898#discussion_r3809825925
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fe/fe-core/src/main/java/org/apache/doris/nereids/jobs/executor/Rewriter.java:
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@@ -690,6 +690,13 @@ public class Rewriter extends AbstractBatchJobExecutor {
topDown(new PushDownAggThroughJoinOnPkFk()),
topDown(new PullUpJoinFromUnionAll())
),
+ // RBO rules that depend on statistics (e.g. InitJoinOrder,
SkewJoin, Eager
+ // aggregation, DecomposeRepeatWithPreAggregation,
DistinctAggStrategySelector)
+ // must be placed AFTER OperativeColumnDerive:
StatsCalculator.computeOlapScan
+ // only fetches column stats of operative slots, so rules
running before the
+ // derivation would fetch stats of all table columns,
polluting the column stats
+ // cache and wasting time on wide tables.
+ custom(RuleType.OPERATIVE_COLUMN_DERIVE,
OperativeColumnDerive::new),
Review Comment:
总共有3处,其他两处不能移除
一处是 mv 内部使用,
一处是rewrite 结束时使用, 因为
1. NormalizeOlapTableStreamScan 会重建节点, 需要重新推导
2. column prune后, operative slots 会变少, 这样cbo阶段传播的colStats也更少
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