Skip to content

Commit

Permalink
SQL: Fix issue with folding of CASE/IIF (#49449)
Browse files Browse the repository at this point in the history 
Add extra checks to prevent ConstantFolding rule to try to fold
the CASE/IIF functions early before the SimplifyCase rule gets applied.

Fixes: #49387

(cherry picked from commit f35c972)
  • Loading branch information
@matriv
matriv committed Nov 22, 2019
1 parent 49bb5fb commit 0c44919
Show file tree
Hide file tree
Showing 2 changed files with 78 additions and 8 deletions.
15 changes: 12 additions & 3 deletions .../sql/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/conditional/Case.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -116,12 +116,21 @@ protected TypeResolution resolveType() {

/**
* All foldable conditions that fold to FALSE should have
* been removed by the {@link Optimizer}.
* been removed by the {@link Optimizer}#SimplifyCase.
*/
@Override
public boolean foldable() {
return (conditions.isEmpty() && elseResult.foldable()) ||
(conditions.size() == 1 && conditions.get(0).condition().foldable() && conditions.get(0).result().foldable());
if (conditions.isEmpty() && elseResult.foldable()) {
return true;
}
if (conditions.size() == 1 && conditions.get(0).condition().foldable()) {
if (conditions.get(0).condition().fold() == Boolean.TRUE) {
return conditions().get(0).result().foldable();
} else {
return elseResult().foldable();
}
}
return false;
}

@Override
Expand Down
71 changes: 66 additions & 5 deletions x-pack/plugin/sql/src/test/java/org/elasticsearch/xpack/sql/optimizer/OptimizerTests.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -671,6 +671,8 @@ public void testSimplifyCaseConditionsFoldWhenFalse() {
new IfConditional(EMPTY, new Equals(EMPTY, TWO, ONE), Literal.of(EMPTY, "bar2")),
new IfConditional(EMPTY, new GreaterThan(EMPTY, getFieldAttribute(), ONE), Literal.of(EMPTY, "foo2")),
Literal.of(EMPTY, "default")));
assertFalse(c.foldable());

Expression e = new SimplifyCase().rule(c);
assertEquals(Case.class, e.getClass());
c = (Case) e;
Expand All @@ -696,13 +698,15 @@ public void testSimplifyCaseConditionsFoldWhenTrue() {
// ELSE 'default'
// END

SimplifyCase rule = new SimplifyCase();
Case c = new Case(EMPTY, Arrays.asList(
new IfConditional(EMPTY, new Equals(EMPTY, getFieldAttribute(), ONE), Literal.of(EMPTY, "foo1")),
new IfConditional(EMPTY, new Equals(EMPTY, ONE, ONE), Literal.of(EMPTY, "bar1")),
new IfConditional(EMPTY, new Equals(EMPTY, TWO, ONE), Literal.of(EMPTY, "bar2")),
new IfConditional(EMPTY, new GreaterThan(EMPTY, getFieldAttribute(), ONE), Literal.of(EMPTY, "foo2")),
Literal.of(EMPTY, "default")));
assertFalse(c.foldable());

SimplifyCase rule = new SimplifyCase();
Expression e = rule.rule(c);
assertEquals(Case.class, e.getClass());
c = (Case) e;
Expand All @@ -713,7 +717,7 @@ public void testSimplifyCaseConditionsFoldWhenTrue() {
assertEquals(TypeResolution.TYPE_RESOLVED, c.typeResolved());
}

public void testSimplifyCaseConditionsFoldCompletely() {
public void testSimplifyCaseConditionsFoldCompletely_FoldableElse() {
// CASE WHEN 1 = 2 THEN 'foo1'
// WHEN 1 = 1 THEN 'foo2'
// ELSE 'default'
Expand All @@ -723,11 +727,13 @@ public void testSimplifyCaseConditionsFoldCompletely() {
//
// 'foo2'

SimplifyCase rule = new SimplifyCase();
Case c = new Case(EMPTY, Arrays.asList(
new IfConditional(EMPTY, new Equals(EMPTY, ONE, TWO), Literal.of(EMPTY, "foo1")),
new IfConditional(EMPTY, new Equals(EMPTY, ONE, ONE), Literal.of(EMPTY, "foo2")),
Literal.of(EMPTY, "default")));
assertFalse(c.foldable());

SimplifyCase rule = new SimplifyCase();
Expression e = rule.rule(c);
assertEquals(Case.class, e.getClass());
c = (Case) e;
Expand All @@ -738,9 +744,34 @@ public void testSimplifyCaseConditionsFoldCompletely() {
assertEquals(TypeResolution.TYPE_RESOLVED, c.typeResolved());
}

public void testSimplifyIif_ConditionTrue() {
public void testSimplifyCaseConditionsFoldCompletely_NonFoldableElse() {
// CASE WHEN 1 = 2 THEN 'foo1'
// ELSE myField
// END
//
// ==>
//
// myField (non-foldable)

Case c = new Case(EMPTY, Arrays.asList(
new IfConditional(EMPTY, new Equals(EMPTY, ONE, TWO), Literal.of(EMPTY, "foo1")),
getFieldAttribute("myField")));
assertFalse(c.foldable());

SimplifyCase rule = new SimplifyCase();
Expression e = rule.rule(c);
assertEquals(Case.class, e.getClass());
c = (Case) e;
assertEquals(0, c.conditions().size());
assertFalse(c.foldable());
assertEquals("myField", Expressions.name(c.elseResult()));
}

public void testSimplifyIif_ConditionTrue_FoldableResult() {
SimplifyCase rule = new SimplifyCase();
Iif iif = new Iif(EMPTY, new Equals(EMPTY, ONE, ONE), Literal.of(EMPTY, "foo"), Literal.of(EMPTY, "bar"));
assertTrue(iif.foldable());

Expression e = rule.rule(iif);
assertEquals(Iif.class, e.getClass());
iif = (Iif) e;
Expand All @@ -750,9 +781,26 @@ public void testSimplifyIif_ConditionTrue() {
assertEquals(TypeResolution.TYPE_RESOLVED, iif.typeResolved());
}

public void testSimplifyIif_ConditionFalse() {
public void testSimplifyIif_ConditionTrue_NonFoldableResult() {
SimplifyCase rule = new SimplifyCase();
Iif iif = new Iif(EMPTY, new Equals(EMPTY, ONE, ONE), getFieldAttribute("myField"), Literal.of(EMPTY, "bar"));
assertFalse(iif.foldable());

Expression e = rule.rule(iif);
assertEquals(Iif.class, e.getClass());
iif = (Iif) e;
assertEquals(1, iif.conditions().size());
assertFalse(iif.foldable());
assertTrue(iif.conditions().get(0).condition().foldable());
assertEquals(Boolean.TRUE, iif.conditions().get(0).condition().fold());
assertEquals("myField", Expressions.name(iif.conditions().get(0).result()));
}

public void testSimplifyIif_ConditionFalse_FoldableResult() {
SimplifyCase rule = new SimplifyCase();
Iif iif = new Iif(EMPTY, new Equals(EMPTY, ONE, TWO), Literal.of(EMPTY, "foo"), Literal.of(EMPTY, "bar"));
assertTrue(iif.foldable());

Expression e = rule.rule(iif);
assertEquals(Iif.class, e.getClass());
iif = (Iif) e;
Expand All @@ -762,6 +810,19 @@ public void testSimplifyIif_ConditionFalse() {
assertEquals(TypeResolution.TYPE_RESOLVED, iif.typeResolved());
}

public void testSimplifyIif_ConditionFalse_NonFoldableResult() {
SimplifyCase rule = new SimplifyCase();
Iif iif = new Iif(EMPTY, new Equals(EMPTY, ONE, TWO), Literal.of(EMPTY, "foo"), getFieldAttribute("myField"));
assertFalse(iif.foldable());

Expression e = rule.rule(iif);
assertEquals(Iif.class, e.getClass());
iif = (Iif) e;
assertEquals(0, iif.conditions().size());
assertFalse(iif.foldable());
assertEquals("myField", Expressions.name(iif.elseResult()));
}

//
// Logical simplifications
//
Expand Down

0 comments on commit 0c44919

Please sign in to comment.