morrySnow commented on code in PR #67172:
URL: https://github.com/apache/doris/pull/67172#discussion_r3869252939
##########
fe/fe-core/src/main/java/org/apache/doris/nereids/rules/exploration/mv/AbstractMaterializedViewRule.java:
##########
@@ -471,6 +470,49 @@ protected List<Plan> doRewrite(StructInfo queryStructInfo,
CascadesContext casca
return rewriteResults;
}
+ Plan buildPartitionCompensationPlan(Plan rewrittenPlan, Plan
baseTablePlan, Plan queryPlan) {
+ Plan queryGlobalLimit = queryPlan.<Plan>collectFirst(
+ node -> isGlobalLimitOrTopN((Plan) node)).orElse(null);
+ if (queryGlobalLimit == null) {
+ return buildCompensationUnion(queryPlan,
Lists.newArrayList(rewrittenPlan, baseTablePlan));
+ }
+ Plan rewrittenGlobalLimit = rewrittenPlan.<Plan>collectFirst(
+ node -> isSameGlobalLimitOrTopN((Plan) node,
queryGlobalLimit)).orElse(null);
+ Plan baseTableGlobalLimit = baseTablePlan.<Plan>collectFirst(
+ node -> isSameGlobalLimitOrTopN((Plan) node,
queryGlobalLimit)).orElse(null);
+ if (rewrittenGlobalLimit == null || baseTableGlobalLimit == null
+ || getOffset(rewrittenGlobalLimit) !=
getOffset(queryGlobalLimit)) {
+ return null;
+ }
+ Plan compensationUnion =
buildCompensationUnion(queryGlobalLimit.child(0), Lists.newArrayList(
+ rewrittenGlobalLimit.child(0), baseTableGlobalLimit.child(0)));
+ return queryPlan.rewriteDownShortCircuit(plan -> plan ==
queryGlobalLimit
+ ? queryGlobalLimit.withChildren(compensationUnion) : plan);
+ }
+
+ private boolean isGlobalLimitOrTopN(Plan plan) {
+ return plan instanceof LogicalTopN
+ || plan instanceof LogicalLimit && ((LogicalLimit<?>)
plan).getPhase() == LimitPhase.GLOBAL;
+ }
+
+ private boolean isSameGlobalLimitOrTopN(Plan plan, Plan queryGlobalLimit) {
+ return plan.getType() == queryGlobalLimit.getType() &&
isGlobalLimitOrTopN(plan);
+ }
Review Comment:
为什么这就可以判定是same？需要注释说明。比如，如果一个plan中有多个 global limit 或者 topn
会怎么样？当前支持哪些情况，有什么限制和前提假设。如果前提假设被破坏会怎么样
##########
fe/fe-core/src/main/java/org/apache/doris/nereids/rules/exploration/mv/AbstractMaterializedViewRule.java:
##########
@@ -471,6 +470,49 @@ protected List<Plan> doRewrite(StructInfo queryStructInfo,
CascadesContext casca
return rewriteResults;
}
+ Plan buildPartitionCompensationPlan(Plan rewrittenPlan, Plan
baseTablePlan, Plan queryPlan) {
+ Plan queryGlobalLimit = queryPlan.<Plan>collectFirst(
+ node -> isGlobalLimitOrTopN((Plan) node)).orElse(null);
+ if (queryGlobalLimit == null) {
+ return buildCompensationUnion(queryPlan,
Lists.newArrayList(rewrittenPlan, baseTablePlan));
+ }
+ Plan rewrittenGlobalLimit = rewrittenPlan.<Plan>collectFirst(
+ node -> isSameGlobalLimitOrTopN((Plan) node,
queryGlobalLimit)).orElse(null);
+ Plan baseTableGlobalLimit = baseTablePlan.<Plan>collectFirst(
+ node -> isSameGlobalLimitOrTopN((Plan) node,
queryGlobalLimit)).orElse(null);
+ if (rewrittenGlobalLimit == null || baseTableGlobalLimit == null
+ || getOffset(rewrittenGlobalLimit) !=
getOffset(queryGlobalLimit)) {
+ return null;
Review Comment:
这里的判断方式比较tricky，需要注释详细说清楚能这么做的原因，前提假设有哪些等，以防止以后功能扩展破坏这里的行为
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