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Do not create local projection for constant in PlanRemoteProjections
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Previously in PlanRemoteProjection, we might create extra assignments for
constants. This would cause plan failure in case of dereference. Essentially
we might rewrite
  `DEREFERENCE(expr, 0)`
to
  `DEREFERENCE(expr, expr1)`
    `expr1 = 0`

This was convenient since we didn't need to handle constant differently.
However, in RowExpressionInterpreter, it is assumed that the second parameter
of DEREFERENCE will be a number, which is no longer true with the change
in PlanRemoteProjection.

This PR changes the behavior of PlanRemoteProjections to not generate additional
projection for constant.
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@rongrong
rongrong authored and Rongrong Zhong committed Apr 26, 2021
1 parent 53ebcda commit 421d7f6
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Showing 2 changed files with 41 additions and 31 deletions.
43 changes: 22 additions & 21 deletions ...in/src/main/java/com/facebook/presto/sql/planner/iterative/rule/PlanRemotePojections.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -251,16 +251,14 @@ public List<ProjectionContext> visitCall(CallExpression call, Void context)
boolean local = !functionMetadata.getImplementationType().equals(THRIFT);

// Break function arguments into local and remote projections first
ImmutableList.Builder<VariableReferenceExpression> newArgumentsBuilder = ImmutableList.builder();
ImmutableList.Builder<RowExpression> newArgumentsBuilder = ImmutableList.builder();
List<ProjectionContext> processedArguments = processArguments(call.getArguments(), newArgumentsBuilder);
List<VariableReferenceExpression> newArguments = newArgumentsBuilder.build();
List<RowExpression> newArguments = newArgumentsBuilder.build();
CallExpression newCall = new CallExpression(
call.getDisplayName(),
call.getFunctionHandle(),
call.getType(),
newArguments.stream()
.map(RowExpression.class::cast)
.collect(toImmutableList()));
newArguments);

if (local) {
if (processedArguments.size() == 1 && !processedArguments.get(0).isRemote()) {
Expand All @@ -280,7 +278,7 @@ else if (!processedArguments.get(processedArguments.size() - 1).isRemote()) {
call.getFunctionHandle(),
call.getType(),
newArguments.stream()
.map(last.getProjections()::get)
.map(argument -> argument instanceof VariableReferenceExpression ? last.getProjections().get(argument) : argument)
.collect(toImmutableList()))),
false));
return projectionContextBuilder.build();
Expand All @@ -306,13 +304,13 @@ else if (!processedArguments.get(processedArguments.size() - 1).isRemote()) {
@Override
public List<ProjectionContext> visitInputReference(InputReferenceExpression reference, Void context)
{
return ImmutableList.of();
throw new IllegalStateException("Optimizers should not see InputReferenceExpression");
}

@Override
public List<ProjectionContext> visitConstant(ConstantExpression literal, Void context)
{
return ImmutableList.of();
throw new IllegalStateException("We should not create ProjectionContext for constants");
}

@Override
Expand All @@ -330,9 +328,9 @@ public List<ProjectionContext> visitVariableReference(VariableReferenceExpressio
@Override
public List<ProjectionContext> visitSpecialForm(SpecialFormExpression specialForm, Void context)
{
ImmutableList.Builder<VariableReferenceExpression> newArgumentsBuilder = ImmutableList.builder();
ImmutableList.Builder<RowExpression> newArgumentsBuilder = ImmutableList.builder();
List<ProjectionContext> processedArguments = processArguments(specialForm.getArguments(), newArgumentsBuilder);
List<VariableReferenceExpression> newArguments = newArgumentsBuilder.build();
List<RowExpression> newArguments = newArgumentsBuilder.build();
if (processedArguments.size() == 1 && !processedArguments.get(0).isRemote()) {
// Arguments do not contain remote projection
return ImmutableList.of();
Expand All @@ -349,7 +347,7 @@ else if (!processedArguments.get(processedArguments.size() - 1).isRemote()) {
specialForm.getForm(),
specialForm.getType(),
newArguments.stream()
.map(last.getProjections()::get)
.map(argument -> argument instanceof VariableReferenceExpression ? last.getProjections().get(argument) : argument)
.collect(toImmutableList()))),
false));
return projectionContextBuilder.build();
Expand All @@ -364,27 +362,30 @@ else if (!processedArguments.get(processedArguments.size() - 1).isRemote()) {
new SpecialFormExpression(
specialForm.getForm(),
specialForm.getType(),
newArguments.stream()
.map(RowExpression.class::cast)
.collect(toImmutableList()))),
newArguments)),
false));
return projectionContextBuilder.build();
}
}

private List<ProjectionContext> processArguments(List<RowExpression> arguments, ImmutableList.Builder<VariableReferenceExpression> newArguments)
private List<ProjectionContext> processArguments(List<RowExpression> arguments, ImmutableList.Builder<RowExpression> newArguments)
{
// Break function arguments into local and remote projections first
ImmutableList.Builder<List<ProjectionContext>> argumentProjections = ImmutableList.builder();

for (RowExpression argument : arguments) {
List<ProjectionContext> argumentProjection = argument.accept(this, null);
if (argumentProjection.isEmpty()) {
VariableReferenceExpression variable = variableAllocator.newVariable(argument);
argumentProjection = ImmutableList.of(new ProjectionContext(ImmutableMap.of(variable, argument), false));
if (argument instanceof ConstantExpression) {
newArguments.add(argument);
}
else {
List<ProjectionContext> argumentProjection = argument.accept(this, null);
if (argumentProjection.isEmpty()) {
VariableReferenceExpression variable = variableAllocator.newVariable(argument);
argumentProjection = ImmutableList.of(new ProjectionContext(ImmutableMap.of(variable, argument), false));
}
argumentProjections.add(argumentProjection);
newArguments.add(getAssignedArgument(argumentProjection));
}
argumentProjections.add(argumentProjection);
newArguments.add(getAssignedArgument(argumentProjection));
}
return mergeProjectionContexts(argumentProjections.build());
}
Expand Down
29 changes: 19 additions & 10 deletions ...c/test/java/com/facebook/presto/sql/planner/iterative/rule/TestPlanRemoteProjections.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -136,6 +136,19 @@ void testLocalOnly()
assertEquals(rewritten.get(0).getProjections().size(), 2);
}

@Test
void testRemoteWithConstantArgument()
{
PlanBuilder planBuilder = new PlanBuilder(TEST_SESSION, new PlanNodeIdAllocator(), getMetadata());

PlanRemotePojections rule = new PlanRemotePojections(getFunctionAndTypeManager());
List<ProjectionContext> rewritten = rule.planRemoteAssignments(Assignments.builder()
.put(planBuilder.variable("a"), planBuilder.rowExpression("unittest.memory.remote_foo(0)"))
.put(planBuilder.variable("b"), planBuilder.rowExpression("unittest.memory.remote_foo()"))
.build(), new PlanVariableAllocator(planBuilder.getTypes().allVariables()));
assertEquals(rewritten.size(), 1);
}

@Test
void testRemoteOnly()
{
Expand Down Expand Up @@ -223,7 +236,7 @@ void testMixedExpressionRewrite()
p.variable("y", INTEGER);
return p.project(
Assignments.builder()
.put(p.variable("a"), p.rowExpression("unittest.memory.remote_foo(x, y + unittest.memory.remote_foo(x))")) // identity
.put(p.variable("a"), p.rowExpression("unittest.memory.remote_foo(1, y + unittest.memory.remote_foo(x))")) // identity
.put(p.variable("b"), p.rowExpression("x IS NULL OR y IS NULL")) // complex expression referenced multiple times
.put(p.variable("c"), p.rowExpression("abs(unittest.memory.remote_foo()) > 0")) // complex expression referenced multiple times
.put(p.variable("d"), p.rowExpression("unittest.memory.remote_foo(x + y, abs(x))")) // literal referenced multiple times
Expand All @@ -233,35 +246,31 @@ void testMixedExpressionRewrite()
.matches(
project(
ImmutableMap.of(
"a", PlanMatchPattern.expression("unittest.memory.remote_foo(x, add)"),
"a", PlanMatchPattern.expression("unittest.memory.remote_foo(1, add)"),
"b", PlanMatchPattern.expression("b"),
"c", PlanMatchPattern.expression("c"),
"d", PlanMatchPattern.expression("d")),
project(
ImmutableMap.of(
"x", PlanMatchPattern.expression("x"),
"add", PlanMatchPattern.expression("y + unittest_memory_remote_foo"),
"b", PlanMatchPattern.expression("b"),
"c", PlanMatchPattern.expression("abs(unittest_memory_remote_foo_7) > expr_8"),
"c", PlanMatchPattern.expression("abs(unittest_memory_remote_foo_7) > 0"),
"d", PlanMatchPattern.expression("d")),
project(
ImmutableMap.<String, ExpressionMatcher>builder()
.put("x", PlanMatchPattern.expression("x"))
.put("y", PlanMatchPattern.expression("y"))
.put("unittest_memory_remote_foo", PlanMatchPattern.expression("unittest.memory.remote_foo(x)"))
.put("b", PlanMatchPattern.expression("b"))
.put("unittest_memory_remote_foo_7", PlanMatchPattern.expression("unittest.memory.remote_foo()"))
.put("expr_8", PlanMatchPattern.expression("expr_8"))
.put("d", PlanMatchPattern.expression("unittest.memory.remote_foo(add_14, abs_16)"))
.put("d", PlanMatchPattern.expression("unittest.memory.remote_foo(add_9, abs_11)"))
.build(),
project(
ImmutableMap.<String, ExpressionMatcher>builder()
.put("x", PlanMatchPattern.expression("x"))
.put("y", PlanMatchPattern.expression("y"))
.put("b", PlanMatchPattern.expression("x IS NULL OR y is NULL"))
.put("expr_8", PlanMatchPattern.expression("0"))
.put("add_14", PlanMatchPattern.expression("x + y"))
.put("abs_16", PlanMatchPattern.expression("abs(x)"))
.put("add_9", PlanMatchPattern.expression("x + y"))
.put("abs_11", PlanMatchPattern.expression("abs(x)"))
.build(),
values(ImmutableMap.of("x", 0, "y", 1)))))));
}
Expand Down

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