Do not push down nondeterministic predicate

gerashegalov · Feb 5, 2015 · c70fb33 · c70fb33
1 parent ba82073
commit c70fb33
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Showing 2 changed files with 33 additions and 2 deletions.
diff --git a/...o-main/src/main/java/com/facebook/presto/sql/planner/optimizations/PredicatePushDown.java b/...o-main/src/main/java/com/facebook/presto/sql/planner/optimizations/PredicatePushDown.java
@@ -164,8 +164,26 @@ public PlanNode visitPlan(PlanNode node, RewriteContext<Expression> context)
  @Override
  public PlanNode visitProject(ProjectNode node, RewriteContext<Expression> context)
  {
- Expression inlinedPredicate = ExpressionTreeRewriter.rewriteWith(new ExpressionSymbolInliner(node.getAssignments()), context.get());
- return context.defaultRewrite(node, inlinedPredicate);
+ Set<Symbol> deterministicSymbols = node.getAssignments().entrySet().stream()
+ .filter(entry -> DeterminismEvaluator.isDeterministic(entry.getValue()))
+ .map(Map.Entry::getKey)
+ .collect(Collectors.toSet());
+
+ java.util.function.Predicate<Expression> deterministic = conjunct -> DependencyExtractor.extractAll(conjunct).stream()
+ .allMatch(deterministicSymbols::contains);
+
+ Map<Boolean, List<Expression>> conjuncts = extractConjuncts(context.get()).stream().collect(Collectors.partitioningBy(deterministic));
+
+ // Push down conjuncts from the inherited predicate that don't depend on non-deterministic assignments
+ PlanNode rewrittenNode = context.defaultRewrite(node,
+ ExpressionTreeRewriter.rewriteWith(new ExpressionSymbolInliner(node.getAssignments()), combineConjuncts(conjuncts.get(true))));
+
+ // All non-deterministic conjuncts, if any, will be in the filter node.
+ if (!conjuncts.get(false).isEmpty()) {
+ rewrittenNode = new FilterNode(idAllocator.getNextId(), rewrittenNode, combineConjuncts(conjuncts.get(false)));
+ }
+
+ return rewrittenNode;
  }
 
  @Override

diff --git a/presto-tests/src/main/java/com/facebook/presto/tests/AbstractTestQueries.java b/presto-tests/src/main/java/com/facebook/presto/tests/AbstractTestQueries.java
@@ -91,6 +91,19 @@ public void selectNull()
  assertQuery("SELECT NULL", "SELECT NULL FROM (SELECT * FROM ORDERS LIMIT 1)");
  }
 
+ @Test
+ public void testNonDeterministicFilter()
+ {
+ MaterializedResult materializedResult = computeActual("SELECT u FROM ( SELECT if(rand() > 0.5, 0, 1) AS u ) WHERE u <> u");
+ assertEquals(materializedResult.getRowCount(), 0);
+
+ materializedResult = computeActual("SELECT u, v FROM ( SELECT if(rand() > 0.5, 0, 1) AS u, 4*4 as v ) WHERE u <> u and v > 10");
+ assertEquals(materializedResult.getRowCount(), 0);
+
+ materializedResult = computeActual("SELECT u, v, w FROM ( SELECT if(rand() > 0.5, 0, 1) AS u, 4*4 as v, 'abc' as w ) WHERE v > 10");
+ assertEquals(materializedResult.getRowCount(), 1);
+ }
+
  @Test
  public void testVarbinary()
  throws Exception