cp to 1.2-dev 'fix the condition for runtime filters (#18496)' (#18860)

cp to 1.2-dev 'fix the condition for runtime filters (#18496)'

Approved by: @ouyuanning, @aunjgr, @sukki37

pkg/sql/plan/agg_pushdown_pullup.go

@@ -122,6 +122,8 @@ func applyAggPushdown(agg, join, leftChild *plan.Node, builder *QueryBuilder) {
 	replaceCol(agg.AggList[0], leftChildTag, colAgg.Col.ColPos, newAggTag, 0)
 }
 
+// agg pushdown only support node->(filter)->inner join->agg for now
+// we can change it to node->agg->(filter)->inner join
 func (builder *QueryBuilder) aggPushDown(nodeID int32) int32 {
 	if builder.optimizerHints != nil && builder.optimizerHints.aggPushDown != 0 {
 		return nodeID
@@ -338,8 +340,8 @@ func applyAggPullup(rootID int32, join, agg, leftScan, rightScan *plan.Node, bui
 }
 
 func (builder *QueryBuilder) aggPullup(rootID, nodeID int32) int32 {
-	// agg pullup only support node->(filter)->inner join->agg for now
-	// we can change it to node->agg->(filter)->inner join
+	// agg pullup only support node->agg->(filter)->inner join  for now
+	// we can change it to node->(filter)->inner join->agg
 	if builder.optimizerHints != nil && builder.optimizerHints.aggPullUp != 0 {
 		return nodeID
 	}

pkg/sql/plan/runtime_filter.go

@@ -85,7 +85,7 @@ func (builder *QueryBuilder) generateRuntimeFilters(nodeID int32) {
 	}
 
 	rightChild := builder.qry.Nodes[node.Children[1]]
-	if node.JoinType != plan.Node_INDEX && rightChild.Stats.Selectivity > 0.5 {
+	if node.JoinType != plan.Node_INDEX && rightChild.Stats.Outcnt > 5000000 {
 		return
 	}