EXPB-3296 Open Calcite PR for lazy Schema lookup

sap-contributions · Dec 18, 2024 · bdd9a0a · bdd9a0a
1 parent d3c0e60
commit bdd9a0a
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Showing 26 changed files with 683 additions and 292 deletions.
diff --git a/core/src/main/java/org/apache/calcite/adapter/clone/CloneSchema.java b/core/src/main/java/org/apache/calcite/adapter/clone/CloneSchema.java
@@ -35,6 +35,8 @@
 import org.apache.calcite.schema.Schemas;
 import org.apache.calcite.schema.Table;
 import org.apache.calcite.schema.impl.AbstractSchema;
+import org.apache.calcite.schema.lookup.LikePattern;
+import org.apache.calcite.schema.lookup.Lookup;
 
 import com.google.common.base.Suppliers;
 import com.google.common.collect.ImmutableList;

diff --git a/core/src/main/java/org/apache/calcite/adapter/jdbc/JdbcBaseSchema.java b/core/src/main/java/org/apache/calcite/adapter/jdbc/JdbcBaseSchema.java
@@ -0,0 +1,94 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you 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 org.apache.calcite.adapter.jdbc;
+
+import org.apache.calcite.linq4j.tree.Expression;
+import org.apache.calcite.rel.type.RelProtoDataType;
+import org.apache.calcite.schema.Function;
+import org.apache.calcite.schema.Schema;
+import org.apache.calcite.schema.SchemaPlus;
+import org.apache.calcite.schema.SchemaVersion;
+import org.apache.calcite.schema.Schemas;
+import org.apache.calcite.schema.Table;
+import org.apache.calcite.schema.lookup.LikePattern;
+import org.apache.calcite.schema.lookup.Lookup;
+
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Set;
+
+import static java.util.Objects.requireNonNull;
+
+/**
+ * Base class for JDBC schemas.
+ */
+public abstract class JdbcBaseSchema implements Schema {
+
+  public abstract Lookup<Table> tables();
+
+
+  @Deprecated @Override public @Nullable Table getTable(String name) {
+    return tables().get(name);
+  }
+
+  @Deprecated @Override public Set<String> getTableNames() {
+    return tables().getNames(LikePattern.any());
+  }
+
+  public abstract Lookup<? extends Schema> subSchemas();
+
+  @Deprecated @Override public @Nullable Schema getSubSchema(String name) {
+    return subSchemas().get(name);
+  }
+
+  @Deprecated @Override public Set<String> getSubSchemaNames() {
+    return subSchemas().getNames(LikePattern.any());
+  }
+
+
+  @Override public @Nullable RelProtoDataType getType(String name) {
+    return null;
+  }
+
+  @Override public Set<String> getTypeNames() {
+    return Collections.emptySet();
+  }
+
+  @Override public final Collection<Function> getFunctions(String name) {
+    return Collections.emptyList();
+  }
+
+  @Override public final Set<String> getFunctionNames() {
+    return Collections.emptySet();
+  }
+
+  @Override public Expression getExpression(@Nullable final SchemaPlus parentSchema,
+      final String name) {
+    requireNonNull(parentSchema, "parentSchema");
+    return Schemas.subSchemaExpression(parentSchema, name, getClass());
+  }
+
+  @Override public boolean isMutable() {
+    return false;
+  }
+
+  @Override public Schema snapshot(final SchemaVersion version) {
+    return this;
+  }
+}
diff --git a/core/src/main/java/org/apache/calcite/adapter/jdbc/JdbcCatalogSchema.java b/core/src/main/java/org/apache/calcite/adapter/jdbc/JdbcCatalogSchema.java
@@ -16,33 +16,31 @@
  */
 package org.apache.calcite.adapter.jdbc;
 
-import com.google.common.collect.ImmutableSet;
-
 import org.apache.calcite.DataContext;
 import org.apache.calcite.linq4j.tree.Expression;
 import org.apache.calcite.linq4j.tree.Expressions;
-import org.apache.calcite.schema.lookup.LikePattern;
-import org.apache.calcite.schema.lookup.Lookup;
 import org.apache.calcite.schema.Schema;
 import org.apache.calcite.schema.SchemaPlus;
 import org.apache.calcite.schema.Schemas;
+import org.apache.calcite.schema.Table;
 import org.apache.calcite.schema.Wrapper;
-import org.apache.calcite.schema.impl.AbstractSchema;
-import org.apache.calcite.schema.lookup.CachingLookup;
 import org.apache.calcite.schema.lookup.IgnoreCaseLookup;
+import org.apache.calcite.schema.lookup.LikePattern;
+import org.apache.calcite.schema.lookup.LoadingCacheLookup;
+import org.apache.calcite.schema.lookup.Lookup;
 import org.apache.calcite.sql.SqlDialect;
 import org.apache.calcite.sql.SqlDialectFactory;
 import org.apache.calcite.sql.SqlDialectFactoryImpl;
 import org.apache.calcite.util.BuiltInMethod;
 
 import com.google.common.base.Suppliers;
+import com.google.common.collect.ImmutableSet;
 
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.SQLException;
-import java.util.Map;
 import java.util.Set;
 import java.util.function.Supplier;
 import javax.sql.DataSource;
@@ -57,11 +55,11 @@
  * an instance of {@link JdbcSchema}.
  *
  * <p>This schema is lazy: it does not compute the list of schema names until
- * the first call to {@link #getSubSchemaMap()}. Then it creates a
- * {@link JdbcSchema} for each schema name. Each JdbcSchema will populate its
+ * the first call to {@link #subSchemas()} and {@link Lookup#get(String)}. Then it creates a
+ * {@link JdbcSchema} for this schema name. Each JdbcSchema will populate its
  * tables on demand.
  */
-public class JdbcCatalogSchema extends AbstractSchema implements Wrapper {
+public class JdbcCatalogSchema extends JdbcBaseSchema implements Wrapper {
   final DataSource dataSource;
   public final SqlDialect dialect;
   final JdbcConvention convention;
@@ -80,12 +78,11 @@ public JdbcCatalogSchema(DataSource dataSource, SqlDialect dialect,
     this.dialect = requireNonNull(dialect, "dialect");
     this.convention = requireNonNull(convention, "convention");
     this.catalog = catalog;
-    this.subSchemas = new CachingLookup<>(new IgnoreCaseLookup<JdbcSchema>() {
-      @Override
-      public @Nullable JdbcSchema get(String name) {
+    this.subSchemas = new LoadingCacheLookup<>(new IgnoreCaseLookup<JdbcSchema>() {
+      @Override public @Nullable JdbcSchema get(String name) {
         try (Connection connection = dataSource.getConnection();
-             ResultSet resultSet =
-                 connection.getMetaData().getSchemas(catalog, name)) {
+            ResultSet resultSet =
+                connection.getMetaData().getSchemas(catalog, name)) {
           while (resultSet.next()) {
             final String schemaName =
                 requireNonNull(resultSet.getString(1),
@@ -98,15 +95,15 @@ public JdbcCatalogSchema(DataSource dataSource, SqlDialect dialect,
         return null;
       }
 
-      @Override
-      public Set<String> getNames(LikePattern pattern) {
+      @Override public Set<String> getNames(LikePattern pattern) {
         final ImmutableSet.Builder<String> builder =
             ImmutableSet.builder();
         try (Connection connection = dataSource.getConnection();
-             ResultSet resultSet =
-                 connection.getMetaData().getSchemas(catalog, pattern.pattern)) {
+            ResultSet resultSet =
+                connection.getMetaData().getSchemas(catalog, pattern.pattern)) {
           while (resultSet.next()) {
-            builder.add(requireNonNull(resultSet.getString(1),
+            builder.add(
+                requireNonNull(resultSet.getString(1),
                     "got null schemaName from the database"));
           }
         } catch (SQLException e) {
@@ -145,6 +142,10 @@ public static JdbcCatalogSchema create(
     return new JdbcCatalogSchema(dataSource, dialect, convention, catalog);
   }
 
+  @Override public Lookup<Table> tables() {
+    return Lookup.empty();
+  }
+
   @Override public Lookup<? extends Schema> subSchemas() {
     return subSchemas;
   }
@@ -157,10 +158,6 @@ private String computeDefaultSchemaName() {
     }
   }
 
-  @Override protected Map<String, Schema> getSubSchemaMap() {
-    throw new UnsupportedOperationException("getSubSchemaMap");
-  }
-
   /** Returns the name of the default sub-schema. */
   public @Nullable String getDefaultSubSchemaName() {
     return defaultSchemaName.get();