[fix](nereids) don't build cte producer if the consumer is empty rela…

…tion (apache#21317)

explain WITH cte_0 AS ( SELECT 1 AS a ) SELECT * from cte_0 t1 join cte_0 t2 on true WHERE false;
before:
```
+----------------------------+
| Explain String             |
+----------------------------+
| PLAN FRAGMENT 0            |
|   OUTPUT EXPRS:            |
|     a[#1]                  |
|     a[#2]                  |
|   PARTITION: UNPARTITIONED |
|                            |
|   VRESULT SINK             |
|                            |
|   1:VEMPTYSET              |
|                            |
| PLAN FRAGMENT 1            |
|   OUTPUT EXPRS:            |
|     a[#0]                  |
|   PARTITION: UNPARTITIONED |
|                            |
|   MultiCastDataSinks       |
|                            |
|   0:VUNION                 |
|      constant exprs:       |
|          1                 |
+----------------------------+
```
after:

```
+----------------------------+
| Explain String             |
+----------------------------+
| PLAN FRAGMENT 0            |
|   OUTPUT EXPRS:            |
|     a[#0]                  |
|     a[#1]                  |
|   PARTITION: UNPARTITIONED |
|                            |
|   VRESULT SINK             |
|                            |
|   0:VEMPTYSET              |
+----------------------------+
```

fe/fe-core/src/main/java/org/apache/doris/nereids/rules/rewrite/BuildCTEAnchorAndCTEProducer.java

@@ -24,6 +24,7 @@
 import org.apache.doris.nereids.trees.plans.logical.LogicalCTE;
 import org.apache.doris.nereids.trees.plans.logical.LogicalCTEAnchor;
 import org.apache.doris.nereids.trees.plans.logical.LogicalCTEProducer;
+import org.apache.doris.nereids.trees.plans.logical.LogicalEmptyRelation;
 import org.apache.doris.nereids.trees.plans.logical.LogicalPlan;
 import org.apache.doris.nereids.trees.plans.logical.LogicalSubQueryAlias;
 import org.apache.doris.qe.ConnectContext;
@@ -47,17 +48,19 @@ private LogicalPlan rewrite(LogicalPlan p, CascadesContext cascadesContext) {
  }
  LogicalCTE logicalCTE = (LogicalCTE) p;
  LogicalPlan child = (LogicalPlan) logicalCTE.child();
- for (int i = logicalCTE.getAliasQueries().size() - 1; i >= 0; i--) {
- LogicalSubQueryAlias s = (LogicalSubQueryAlias) logicalCTE.getAliasQueries().get(i);
- CTEId id = logicalCTE.findCTEId(s.getAlias());
- if (cascadesContext.cteReferencedCount(id)
- <= ConnectContext.get().getSessionVariable().inlineCTEReferencedThreshold
- || !ConnectContext.get().getSessionVariable().getEnablePipelineEngine()) {
- continue;
+ if (!(child instanceof LogicalEmptyRelation)) {
+ for (int i = logicalCTE.getAliasQueries().size() - 1; i >= 0; i--) {
+ LogicalSubQueryAlias s = (LogicalSubQueryAlias) logicalCTE.getAliasQueries().get(i);
+ CTEId id = logicalCTE.findCTEId(s.getAlias());
+ if (cascadesContext.cteReferencedCount(id)
+ <= ConnectContext.get().getSessionVariable().inlineCTEReferencedThreshold
+ || !ConnectContext.get().getSessionVariable().getEnablePipelineEngine()) {
+ continue;
+ }
+ LogicalCTEProducer logicalCTEProducer = new LogicalCTEProducer(
+ rewrite((LogicalPlan) s.child(), cascadesContext), id);
+ child = new LogicalCTEAnchor(logicalCTEProducer, child, id);
  }
- LogicalCTEProducer logicalCTEProducer = new LogicalCTEProducer(
- rewrite((LogicalPlan) s.child(), cascadesContext), id);
- child = new LogicalCTEAnchor(logicalCTEProducer, child, id);
  }
  return child;
  }

regression-test/suites/nereids_syntax_p0/cte.groovy

@@ -301,5 +301,10 @@ suite("cte") {
  exception = "[cte1] cannot be used more than once"
  }
 
+ explain {
+ sql("WITH cte_0 AS ( SELECT 1 AS a ) SELECT * from cte_0 t1 join cte_0 t2 on true WHERE false;")
+ notContains "MultiCastDataSinks"
+ }
+
 }