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[opt](nereids) estimate broadcast cost by a new formula (#18744)

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estimate broadcast cost by an experience formula: beNumber^0.5 * rowCount
1. sender number and receiver number is not available at RBO stage now, so we use beNumber
2. senders and receivers work in parallel, that why we use square of beNumber
This commit is contained in:
minghong
2023-04-19 12:14:55 +08:00
committed by GitHub
parent 7d6b1a115a
commit 446db3def6
1 changed files with 4 additions and 1 deletions
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5
fe/fe-core/src/main/java/org/apache/doris/nereids/cost/CostModelV1.java
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@ -174,10 +174,13 @@ class CostModelV1 extends PlanVisitor<Cost, PlanContext> {
|| childStatistics.getRowCount() > rowsLimit) {
return CostV1.of(Double.MAX_VALUE, Double.MAX_VALUE, Double.MAX_VALUE);
}
// estimate broadcast cost by an experience formula: beNumber^0.5 * rowCount
// - sender number and receiver number is not available at RBO stage now, so we use beNumber
// - senders and receivers work in parallel, that why we use square of beNumber
return CostV1.of(
0,
0,
childStatistics.getRowCount() * beNumber);
childStatistics.getRowCount() * Math.pow(beNumber, 0.5));
}