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Do not use FieldExistsQuery over REF that is arg of NON_NULLABLE function #15280

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Jan 10, 2024
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Do not use FieldExistsQuery over REF that is arg of NON_NULLABLE function #15280

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73 changes: 33 additions & 40 deletions server/src/main/java/io/crate/expression/predicate/NotPredicate.java
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Original file line number Diff line number Diff line change
Expand Up @@ -99,25 +99,20 @@ public Boolean evaluate(TransactionContext txnCtx, NodeContext nodeCtx, Input<Bo
private final NullabilityVisitor INNER_VISITOR = new NullabilityVisitor();

private static class NullabilityContext {
private final HashSet<Reference> references = new HashSet<>();
private boolean removeNullValues = false;
private boolean useNotQuery = false;
private final HashSet<Reference> nullableReferences = new HashSet<>();
private boolean isNullable = true;
private boolean enforceThreeValuedLogic = false;

void add(Reference symbol) {
references.add(symbol);
void collectNullableReferences(Reference symbol) {
nullableReferences.add(symbol);
}

Set<Reference> references() {
return references;
Set<Reference> nullableReferences() {
return nullableReferences;
}

boolean useNotQuery() {
return useNotQuery && !enforceThreeValuedLogic;
}

boolean useFieldExistQuery() {
return removeNullValues && !enforceThreeValuedLogic;
boolean enforceThreeValuedLogic() {
return enforceThreeValuedLogic;
}
}

Expand All @@ -127,7 +122,10 @@ private static class NullabilityVisitor extends SymbolVisitor<NullabilityContext

@Override
public Void visitReference(Reference symbol, NullabilityContext context) {
context.add(symbol);
// if ref is nullable and all its parents are nullable
if (symbol.isNullable() && context.isNullable) {
context.collectNullableReferences(symbol);
}
return null;
}

Expand All @@ -142,27 +140,28 @@ public Void visitFunction(Function function, NullabilityContext context) {
var b = function.arguments().get(1);
if (a instanceof Reference ref && b instanceof Literal<?>) {
if (ref.valueType().id() == DataTypes.UNTYPED_OBJECT.id()) {
context.removeNullValues = true;
return null;
}
}
} else if (Ignore3vlFunction.NAME.equals(functionName)) {
context.useNotQuery = true;
context.isNullable = false;
return null;
} else {
var signature = function.signature();
if (signature.hasFeature(Feature.NULLABLE)) {
context.removeNullValues = true;
} else if (signature.hasFeature(Feature.NON_NULLABLE)) {
context.useNotQuery = true;
} else {
if (signature.hasFeature(Feature.NON_NULLABLE)) {
context.isNullable = false;
} else if (!signature.hasFeature(Feature.NULLABLE)) {
// default case
context.enforceThreeValuedLogic = true;
return null;
}
}
// saves and restores isNullable of the current context
// such that any non-nullables observed from the left arg is not transferred to the right arg.
boolean isNullable = context.isNullable;
for (Symbol arg : function.arguments()) {
arg.accept(this, context);
context.isNullable = isNullable;
Comment on lines +159 to +164
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Thank you for reviewing @mkleen . I think the static method of was the cause of the confusion. Please check again.

}
return null;
}
Expand Down Expand Up @@ -202,31 +201,25 @@ public Query toQuery(Function input, LuceneQueryBuilder.Context context) {
NullabilityContext ctx = new NullabilityContext();
arg.accept(INNER_VISITOR, ctx);

if (ctx.useFieldExistQuery()) {
// we can optimize with a field exist query and filter out all null values which will reduce the
// result set of the query
BooleanQuery.Builder builder = new BooleanQuery.Builder();
builder.add(notX, BooleanClause.Occur.MUST);
for (Reference reference : ctx.references()) {
if (reference.isNullable()) {
var refExistsQuery = IsNullPredicate.refExistsQuery(reference, context, false);
if (refExistsQuery != null) {
builder.add(refExistsQuery, BooleanClause.Occur.MUST);
}
}
}
return builder.build();
} else if (ctx.useNotQuery()) {
return new BooleanQuery.Builder()
.add(notX, Occur.MUST)
.build();
} else {
if (ctx.enforceThreeValuedLogic()) {
// we require strict 3vl logic, therefore we need to add the function as generic function filter
// which is less efficient
return new BooleanQuery.Builder()
.add(notX, Occur.MUST)
.add(LuceneQueryBuilder.genericFunctionFilter(input, context), Occur.FILTER)
.build();
} else {
BooleanQuery.Builder builder = new BooleanQuery.Builder();
builder.add(notX, BooleanClause.Occur.MUST);
for (Reference nullableRef : ctx.nullableReferences()) {
// we can optimize with a field exist query and filter out all null values which will reduce the
// result set of the query
var refExistsQuery = IsNullPredicate.refExistsQuery(nullableRef, context, false);
if (refExistsQuery != null) {
builder.add(refExistsQuery, BooleanClause.Occur.MUST);
}
}
return builder.build();
}
}
}
30 changes: 30 additions & 0 deletions server/src/test/java/io/crate/lucene/CommonQueryBuilderTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -750,10 +750,40 @@ public void test_neq_operator_on_nullable_and_not_nullable_args_filters_nulls()
}
}

// tracks a bug : https://github.com/crate/crate/pull/15280#issue-2064743724
@Test
public void test_neq_operator_on_nullable_and_not_nullable_args_does_not_filter_nulls_from_non_nullable_arg() throws Exception {
long[] oid = new long[] {123, 124};
int[] oidIdx = new int[]{0};
try (QueryTester tester = new QueryTester.Builder(
THREAD_POOL,
clusterService,
Version.CURRENT,
"create table t (a int, b int)",
() -> oid[oidIdx[0]++]) // oid mapping: a: 123, b: 124
.indexValues(List.of("a", "b"), null, null)
.indexValues(List.of("a", "b"), null, 2)
.indexValues(List.of("a", "b"), 2, null)
.indexValues(List.of("a", "b"), 2, 2)
.build()) {
assertThat(oidIdx[0]).isEqualTo(2);
Query query = tester.toQuery("a != b||1"); // where a is nullable and b||1 is not null
assertThat(query).hasToString(String.format("+(+*:* -(a = concat(b, '1'))) +FieldExistsQuery [field=%s]", oid[0]));
assertThat(tester.runQuery("b", "a != b||1")).containsExactlyInAnyOrder(2, null);
}
}

// tracks a bug: https://github.com/crate/crate/issues/15232
@Test
public void test_cannot_use_field_exists_query_on_args_of_coalesce_function() {
Query query = convert("coalesce(x, y) <> 0");
assertThat(query).hasToString("+(+*:* -(coalesce(x, y) = 0)) #(NOT (coalesce(x, y) = 0))");
}

// tracks a bug : https://github.com/crate/crate/issues/15265
@Test
public void test_nested_not_operators() {
Query query = convert("not (y is not null)");
assertThat(query).hasToString("+(+*:* -FieldExistsQuery [field=y])");
}
}
18 changes: 18 additions & 0 deletions server/src/testFixtures/java/io/crate/testing/QueryTester.java
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@

import io.crate.analyze.relations.DocTableRelation;
import io.crate.common.collections.Iterables;
import io.crate.common.collections.Lists2;
import io.crate.data.Input;
import io.crate.execution.dml.IndexItem;
import io.crate.execution.dml.Indexer;
Expand Down Expand Up @@ -150,6 +151,23 @@ public Builder indexValue(String column, Object value) throws IOException {
return this;
}

public Builder indexValues(List<String> columns, Object ... values) throws IOException {
MapperService mapperService = indexEnv.mapperService();
Indexer indexer = new Indexer(
table.concreteIndices()[0],
table,
plannerContext.transactionContext(),
plannerContext.nodeContext(),
mapperService::getLuceneFieldType,
Lists2.map(columns, c -> table.getReference(ColumnIdent.fromPath(c))),
null
);
var item = new IndexItem.StaticItem("dummy-id", List.of(), values, -1L, -1L);
ParsedDocument parsedDocument = indexer.index(item);
indexEnv.writer().addDocument(parsedDocument.doc());
return this;
}

private LuceneBatchIterator getIterator(ColumnIdent column, Query query) {
InputFactory inputFactory = new InputFactory(plannerContext.nodeContext());
InputFactory.Context<LuceneCollectorExpression<?>> ctx = inputFactory.ctxForRefs(
Expand Down