we use a map to record rewrite cte children result to avoid rewrite
twice in cost based rewritter. However, we record cte outer and
inner in one map, and use null as outer result's key, use cte id as
inner result's key. This is wrong, because every anchor has an outer,
and we could only record one outer. So when we use the cache in cost
based rewritter, we get wrong outer plan from the cache. Then the error
will be thrown as below:
```
Caused by: java.lang.IllegalArgumentException: Stats for CTE: CTEId#1 not found
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:143) ~[guava-32.1.2-jre.jar:?]
at org.apache.doris.nereids.stats.StatsCalculator.visitLogicalCTEConsumer(StatsCalculator.java:1049) ~[classes/:?]
at org.apache.doris.nereids.stats.StatsCalculator.visitLogicalCTEConsumer(StatsCalculator.java:147) ~[classes/:?]
at org.apache.doris.nereids.trees.plans.logical.LogicalCTEConsumer.accept(LogicalCTEConsumer.java:111) ~[classes/:?]
at org.apache.doris.nereids.stats.StatsCalculator.estimate(StatsCalculator.java:222) ~[classes/:?]
at org.apache.doris.nereids.stats.StatsCalculator.estimate(StatsCalculator.java:200) ~[classes/:?]
at org.apache.doris.nereids.jobs.cascades.DeriveStatsJob.execute(DeriveStatsJob.java:108) ~[classes/:?]
at org.apache.doris.nereids.jobs.scheduler.SimpleJobScheduler.executeJobPool(SimpleJobScheduler.java:39) ~[classes/:?]
at org.apache.doris.nereids.jobs.executor.Optimizer.execute(Optimizer.java:51) ~[classes/:?]
at org.apache.doris.nereids.jobs.rewrite.CostBasedRewriteJob.getCost(CostBasedRewriteJob.java:98) ~[classes/:?]
at org.apache.doris.nereids.jobs.rewrite.CostBasedRewriteJob.execute(CostBasedRewriteJob.java:64) ~[classes/:?]
at org.apache.doris.nereids.jobs.executor.AbstractBatchJobExecutor.execute(AbstractBatchJobExecutor.java:119) ~[classes/:?]
at org.apache.doris.nereids.rules.rewrite.RewriteCteChildren.visit(RewriteCteChildren.java:72) ~[classes/:?]
at org.apache.doris.nereids.rules.rewrite.RewriteCteChildren.visit(RewriteCteChildren.java:56) ~[classes/:?]
at org.apache.doris.nereids.trees.plans.visitor.PlanVisitor.visitLogicalSink(PlanVisitor.java:118) ~[classes/:?]
at org.apache.doris.nereids.trees.plans.visitor.SinkVisitor.visitLogicalResultSink(SinkVisitor.java:72) ~[classes/:?]
at org.apache.doris.nereids.trees.plans.logical.LogicalResultSink.accept(LogicalResultSink.java:58) ~[classes/:?]
at org.apache.doris.nereids.rules.rewrite.RewriteCteChildren.visitLogicalCTEAnchor(RewriteCteChildren.java:86) ~[classes/:?]
at org.apache.doris.nereids.rules.rewrite.RewriteCteChildren.visitLogicalCTEAnchor(RewriteCteChildren.java:56) ~[classes/:?]
at org.apache.doris.nereids.trees.plans.logical.LogicalCTEAnchor.accept(LogicalCTEAnchor.java:60) ~[classes/:?]
at org.apache.doris.nereids.rules.rewrite.RewriteCteChildren.visitLogicalCTEAnchor(RewriteCteChildren.java:86) ~[classes/:?]
at org.apache.doris.nereids.rules.rewrite.RewriteCteChildren.visitLogicalCTEAnchor(RewriteCteChildren.java:56) ~[classes/:?]
at org.apache.doris.nereids.trees.plans.logical.LogicalCTEAnchor.accept(LogicalCTEAnchor.java:60) ~[classes/:?]
at org.apache.doris.nereids.rules.rewrite.RewriteCteChildren.rewriteRoot(RewriteCteChildren.java:67) ~[classes/:?]
at org.apache.doris.nereids.jobs.rewrite.CustomRewriteJob.execute(CustomRewriteJob.java:58) ~[classes/:?]
at org.apache.doris.nereids.jobs.executor.AbstractBatchJobExecutor.execute(AbstractBatchJobExecutor.java:119) ~[classes/:?]
at org.apache.doris.nereids.NereidsPlanner.rewrite(NereidsPlanner.java:275) ~[classes/:?]
at org.apache.doris.nereids.NereidsPlanner.plan(NereidsPlanner.java:218) ~[classes/:?]
at org.apache.doris.nereids.NereidsPlanner.plan(NereidsPlanner.java:118) ~[classes/:?]
at org.apache.doris.nereids.trees.plans.commands.ExplainCommand.run(ExplainCommand.java:81) ~[classes/:?]
at org.apache.doris.qe.StmtExecutor.executeByNereids(StmtExecutor.java:550) ~[classes/:?]
```
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