seawinde commented on code in PR #67172:
URL: https://github.com/apache/doris/pull/67172#discussion_r3885199212
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fe/fe-core/src/main/java/org/apache/doris/nereids/rules/exploration/mv/AbstractMaterializedViewRule.java:
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@@ -471,6 +470,58 @@ protected List<Plan> doRewrite(StructInfo queryStructInfo,
CascadesContext casca
return rewriteResults;
}
+ // Partition compensation only supports one global limit/topN in each
plan. When this invariant
+ // is not met, return null so the caller skips the rewrite instead of
changing query semantics.
+ Plan buildPartitionCompensationPlan(Plan rewrittenPlan, Plan
baseTablePlan, Plan queryPlan) {
+ List<Plan> queryGlobalLimits = queryPlan.collectToList(node ->
isGlobalLimitOrTopN((Plan) node));
+ List<Plan> rewrittenGlobalLimits = rewrittenPlan.collectToList(
+ node -> isGlobalLimitOrTopN((Plan) node));
+ List<Plan> baseTableGlobalLimits = baseTablePlan.collectToList(
+ node -> isGlobalLimitOrTopN((Plan) node));
+ if (queryGlobalLimits.isEmpty()) {
+ return rewrittenGlobalLimits.isEmpty() &&
baseTableGlobalLimits.isEmpty()
+ ? buildCompensationUnion(queryPlan,
Lists.newArrayList(rewrittenPlan, baseTablePlan)) : null;
+ }
+ if (queryGlobalLimits.size() != 1
+ || rewrittenGlobalLimits.size() != 1 ||
baseTableGlobalLimits.size() != 1) {
+ return null;
+ }
+ Plan queryGlobalLimit = queryGlobalLimits.get(0);
+ Plan rewrittenGlobalLimit = rewrittenGlobalLimits.get(0);
+ Plan baseTableGlobalLimit = baseTableGlobalLimits.get(0);
+ // Rewriting can change the limit value and order-key expressions, but
preserves the outer
+ // operator kind. The offset must still match because it cannot be
safely adjusted after UNION.
+ if (rewrittenGlobalLimit.getType() != queryGlobalLimit.getType()
+ || baseTableGlobalLimit.getType() != queryGlobalLimit.getType()
+ || getOffset(rewrittenGlobalLimit) !=
getOffset(queryGlobalLimit)
+ || getOffset(baseTableGlobalLimit) !=
getOffset(queryGlobalLimit)) {
+ return null;
+ }
+ Plan compensationUnion =
buildCompensationUnion(queryGlobalLimit.child(0), Lists.newArrayList(
Review Comment:
已按该 P1 建议修复，提交 d891c1f2309。partition compensation 现在要求三棵 plan 的唯一 Global
Limit/TopN 都位于根节点；query、MV、base 任一存在外层 Project 或其他非根形态时直接放弃 rewrite，避免 UNION 按
ordinal 合并不同语义的表达式。新增回归 partition_compensation_project_mv，验证 stale partition 下
MV 不被选择、无 VUNION，且 rewrite 开关前后结果一致。提交 90f81c138d3。
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