Support char/varchar cast projection pushdown in oracle

plugin/trino-base-jdbc/src/main/java/io/trino/plugin/jdbc/expression/AbstractRewriteCast.java

@@ -0,0 +1,95 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.trino.plugin.jdbc.expression;
+
+import io.trino.matching.Capture;
+import io.trino.matching.Captures;
+import io.trino.matching.Pattern;
+import io.trino.plugin.base.projection.ProjectFunctionRule;
+import io.trino.plugin.jdbc.JdbcColumnHandle;
+import io.trino.plugin.jdbc.JdbcExpression;
+import io.trino.plugin.jdbc.JdbcTypeHandle;
+import io.trino.spi.connector.ConnectorSession;
+import io.trino.spi.connector.ConnectorTableHandle;
+import io.trino.spi.expression.Call;
+import io.trino.spi.expression.ConnectorExpression;
+import io.trino.spi.expression.Variable;
+import io.trino.spi.type.Type;
+
+import java.util.Optional;
+import java.util.function.BiFunction;
+
+import static io.trino.matching.Capture.newCapture;
+import static io.trino.plugin.base.expression.ConnectorExpressionPatterns.argument;
+import static io.trino.plugin.base.expression.ConnectorExpressionPatterns.argumentCount;
+import static io.trino.plugin.base.expression.ConnectorExpressionPatterns.call;
+import static io.trino.plugin.base.expression.ConnectorExpressionPatterns.functionName;
+import static io.trino.plugin.base.expression.ConnectorExpressionPatterns.variable;
+import static io.trino.spi.expression.StandardFunctions.CAST_FUNCTION_NAME;
+import static java.util.Objects.requireNonNull;
+
+public abstract class AbstractRewriteCast
+        implements ProjectFunctionRule<JdbcExpression, ParameterizedExpression>
+{
+    private static final Capture<Variable> VALUE = newCapture();
+
+    private final BiFunction<ConnectorSession, Type, String> jdbcTypeProvider;
+
+    protected abstract Optional<JdbcTypeHandle> toJdbcTypeHandle(JdbcTypeHandle sourceType, Type targetType);
+
+    public AbstractRewriteCast(BiFunction<ConnectorSession, Type, String> jdbcTypeProvider)
+    {
+        this.jdbcTypeProvider = requireNonNull(jdbcTypeProvider, "jdbcTypeProvider is null");
+    }
+
+    protected String buildCast(@SuppressWarnings("unused") Type sourceType, @SuppressWarnings("unused") Type targetType, String expression, String castType)
+    {
+        return "CAST(%s AS %s)".formatted(expression, castType);
+    }
+
+    @Override
+    public Pattern<Call> getPattern()
+    {
+        return call()
+                .with(functionName().equalTo(CAST_FUNCTION_NAME))
+                .with(argumentCount().equalTo(1))
+                .with(argument(0).matching(variable().capturedAs(VALUE)));
+    }
+
+    @Override
+    public Optional<JdbcExpression> rewrite(ConnectorTableHandle handle, ConnectorExpression castExpression, Captures captures, RewriteContext<ParameterizedExpression> context)
+    {
+        Variable variable = captures.get(VALUE);
+        JdbcTypeHandle sourceTypeJdbcHandle = ((JdbcColumnHandle) context.getAssignment(variable.getName())).getJdbcTypeHandle();
+        Type targetType = castExpression.getType();
+        Optional<JdbcTypeHandle> targetJdbcTypeHandle = toJdbcTypeHandle(sourceTypeJdbcHandle, targetType);
+
+        if (targetJdbcTypeHandle.isEmpty()) {
+            return Optional.empty();
+        }
+
+        Optional<ParameterizedExpression> value = context.rewriteExpression(variable);
+        if (value.isEmpty()) {
+            return Optional.empty();
+        }
+
+        Type sourceType = variable.getType();
+        String castType = jdbcTypeProvider.apply(context.getSession(), targetType);
+
+        return Optional.of(new JdbcExpression(
+                buildCast(sourceType, targetType, value.get().expression(), castType),
+                value.get().parameters(),
+                targetJdbcTypeHandle.get()));
+    }
+}

plugin/trino-base-jdbc/src/test/java/io/trino/plugin/jdbc/BaseJdbcCastPushdownTest.java

@@ -0,0 +1,94 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.trino.plugin.jdbc;
+
+import io.trino.sql.planner.plan.ProjectNode;
+import io.trino.testing.AbstractTestQueryFramework;
+import io.trino.testing.sql.SqlExecutor;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.Optional;
+
+import static java.util.Objects.requireNonNull;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+public abstract class BaseJdbcCastPushdownTest
+        extends AbstractTestQueryFramework
+{
+    protected abstract String leftTable();
+
+    protected abstract String rightTable();
+
+    protected abstract SqlExecutor onRemoteDatabase();
+
+    protected abstract List<CastTestCase> supportedCastTypePushdown();
+
+    protected abstract List<CastTestCase> unsupportedCastTypePushdown();
+
+    protected abstract List<CastTestCase> failCast();
+
+    @Test
+    public void testProjectionPushdownWithCast()
+    {
+        for (CastTestCase testCase : supportedCastTypePushdown()) {
+            assertThat(query("SELECT CAST(%s AS %s) FROM %s".formatted(testCase.sourceColumn(), testCase.castType(), leftTable())))
+                    .isFullyPushedDown();
+        }
+
+        for (CastTestCase testCase : unsupportedCastTypePushdown()) {
+            assertThat(query("SELECT CAST(%s AS %s) FROM %s".formatted(testCase.sourceColumn(), testCase.castType(), leftTable())))
+                    .isNotFullyPushedDown(ProjectNode.class);
+        }
+    }
+
+    @Test
+    public void testJoinPushdownWithCast()
+    {
+        for (CastTestCase testCase : supportedCastTypePushdown()) {
+            assertThat(query("SELECT l.id FROM %s l JOIN %s r ON CAST(l.%s AS %s) = r.%s".formatted(leftTable(), rightTable(), testCase.sourceColumn(), testCase.castType(), testCase.targetColumn().orElseThrow())))
+                    .isFullyPushedDown();
+        }
+
+        for (CastTestCase testCase : unsupportedCastTypePushdown()) {
+            assertThat(query("SELECT l.id FROM %s l JOIN %s r ON CAST(l.%s AS %s) = r.%s".formatted(leftTable(), rightTable(), testCase.sourceColumn(), testCase.castType(), testCase.targetColumn().orElseThrow())))
+                    .joinIsNotFullyPushedDown();
+        }
+    }
+
+    @Test
+    public void testCastFails()
+    {
+        for (CastTestCase testCase : failCast()) {
+            assertThatThrownBy(() -> getQueryRunner().execute("SELECT CAST(%s AS %s) FROM %s".formatted(testCase.sourceColumn(), testCase.castType(), leftTable())))
+                    .hasMessageMatching("(.*)Cannot cast (.*) to (.*)");
+        }
+    }
+
+    public record CastTestCase(String sourceColumn, String castType, Optional<String> targetColumn)
+    {
+        public CastTestCase(String sourceColumn, String castType)
+        {
+            this(sourceColumn, castType, Optional.empty());
+        }
+
+        public CastTestCase
+        {
+            requireNonNull(sourceColumn, "sourceColumn is null");
+            requireNonNull(castType, "castType is null");
+            requireNonNull(targetColumn, "targetColumn is null");
+        }
+    }
+}

plugin/trino-base-jdbc/src/test/java/io/trino/plugin/jdbc/CastDataTypeTestTable.java

@@ -0,0 +1,103 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.trino.plugin.jdbc;
+
+import io.trino.testing.sql.SqlExecutor;
+import io.trino.testing.sql.TemporaryRelation;
+import io.trino.testing.sql.TestTable;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.IntStream;
+
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkState;
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static io.airlift.testing.Closeables.closeAll;
+import static java.util.Objects.requireNonNull;
+import static java.util.stream.Collectors.joining;
+
+public final class CastDataTypeTestTable
+        implements TemporaryRelation
+{
+    private final List<TestCaseInput> testCaseRows = new ArrayList<>();
+    private final int rowCount;
+
+    private TestTable testTable;
+
+    private CastDataTypeTestTable(int rowCount)
+    {
+        this.rowCount = rowCount;
+    }
+
+    public static CastDataTypeTestTable create(int rowCount)
+    {
+        return new CastDataTypeTestTable(rowCount);
+    }
+
+    public CastDataTypeTestTable addColumn(String columnName, String columnType, List<Object> inputValues)
+    {
+        checkArgument(rowCount == inputValues.size(), "Expected input size: %s, but found: %s", rowCount, inputValues.size());
+        testCaseRows.add(new TestCaseInput(columnName, columnType, inputValues));
+        return this;
+    }
+
+    public CastDataTypeTestTable execute(SqlExecutor sqlExecutor, String tableNamePrefix)
+    {
+        checkState(!testCaseRows.isEmpty(), "No test case rows");
+        List<String> columnsWithType = new ArrayList<>();
+        for (TestCaseInput input : testCaseRows) {
+            columnsWithType.add("%s %s".formatted(input.columnName(), input.columnType()));
+        }
+        String tableDefinition = columnsWithType.stream()
+                .collect(joining(", ", "(", ")"));
+
+        List<String> rowsToInsert = IntStream.range(0, rowCount)
+                .mapToObj(rowId -> testCaseRows.stream()
+                        .map(TestCaseInput::inputValues)
+                        .map(rows -> rows.get(rowId))
+                        .map(String::valueOf)
+                        .collect(joining(",")))
+                .collect(toImmutableList());
+        testTable = new TestTable(sqlExecutor, tableNamePrefix, tableDefinition, rowsToInsert);
+        return this;
+    }
+
+    @Override
+    public String getName()
+    {
+        return testTable.getName();
+    }
+
+    @Override
+    public void close()
+    {
+        try {
+            closeAll(testTable);
+        }
+        catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public record TestCaseInput(String columnName, String columnType, List<Object> inputValues)
+    {
+        public TestCaseInput
+        {
+            requireNonNull(columnName, "columnName is null");
+            requireNonNull(columnType, "columnType is null");
+            inputValues = new ArrayList<>(requireNonNull(inputValues, "inputValues is null"));
+        }
+    }
+}

plugin/trino-oracle/src/main/java/io/trino/plugin/oracle/OracleClient.java

@@ -21,6 +21,8 @@
 import io.trino.plugin.base.aggregation.AggregateFunctionRule;
 import io.trino.plugin.base.expression.ConnectorExpressionRewriter;
 import io.trino.plugin.base.mapping.IdentifierMapping;
+import io.trino.plugin.base.projection.ProjectFunctionRewriter;
+import io.trino.plugin.base.projection.ProjectFunctionRule;
 import io.trino.plugin.jdbc.BaseJdbcClient;
 import io.trino.plugin.jdbc.BaseJdbcConfig;
 import io.trino.plugin.jdbc.BooleanWriteFunction;
@@ -165,10 +167,10 @@ public class OracleClient
     private static final int MAX_BYTES_PER_CHAR = 4;
 
     private static final int ORACLE_VARCHAR2_MAX_BYTES = 4000;
-    private static final int ORACLE_VARCHAR2_MAX_CHARS = ORACLE_VARCHAR2_MAX_BYTES / MAX_BYTES_PER_CHAR;
+    public static final int ORACLE_VARCHAR2_MAX_CHARS = ORACLE_VARCHAR2_MAX_BYTES / MAX_BYTES_PER_CHAR;
 
     private static final int ORACLE_CHAR_MAX_BYTES = 2000;
-    private static final int ORACLE_CHAR_MAX_CHARS = ORACLE_CHAR_MAX_BYTES / MAX_BYTES_PER_CHAR;
+    public static final int ORACLE_CHAR_MAX_CHARS = ORACLE_CHAR_MAX_BYTES / MAX_BYTES_PER_CHAR;
 
     private static final int PRECISION_OF_UNSPECIFIED_NUMBER = 127;
 
@@ -215,6 +217,7 @@ public class OracleClient
 
     private final boolean synonymsEnabled;
     private final ConnectorExpressionRewriter<ParameterizedExpression> connectorExpressionRewriter;
+    private final ProjectFunctionRewriter<JdbcExpression, ParameterizedExpression> projectFunctionRewriter;
     private final AggregateFunctionRewriter<JdbcExpression, ?> aggregateFunctionRewriter;
     private final Optional<Integer> fetchSize;
 
@@ -243,6 +246,12 @@ public OracleClient(
                 .add(new RewriteStringComparison())
                 .build();
 
+        this.projectFunctionRewriter = new ProjectFunctionRewriter<>(
+                this.connectorExpressionRewriter,
+                ImmutableSet.<ProjectFunctionRule<JdbcExpression, ParameterizedExpression>>builder()
+                        .add(new RewriteCast((session, type) -> toWriteMapping(session, type).getDataType()))
+                        .build());
+
         JdbcTypeHandle bigintTypeHandle = new JdbcTypeHandle(TRINO_BIGINT_TYPE, Optional.of("NUMBER"), Optional.of(0), Optional.of(0), Optional.empty(), Optional.empty());
         this.aggregateFunctionRewriter = new AggregateFunctionRewriter<>(
                 connectorExpressionRewriter,
@@ -559,6 +568,12 @@ public Optional<ParameterizedExpression> convertPredicate(ConnectorSession sessi
         return connectorExpressionRewriter.rewrite(session, expression, assignments);
     }
 
+    @Override
+    public Optional<JdbcExpression> convertProjection(ConnectorSession session, JdbcTableHandle handle, ConnectorExpression expression, Map<String, ColumnHandle> assignments)
+    {
+        return projectFunctionRewriter.rewrite(session, handle, expression, assignments);
+    }
+
     private static Optional<JdbcTypeHandle> toTypeHandle(DecimalType decimalType)
     {
         return Optional.of(new JdbcTypeHandle(OracleTypes.NUMBER, Optional.of("NUMBER"), Optional.of(decimalType.getPrecision()), Optional.of(decimalType.getScale()), Optional.empty(), Optional.empty()));