[CALCITE-6728] Introduce new methods to lookup tables and schemas ins…

…ide schemas
sap-contributions · Dec 19, 2024 · c204e6f · c204e6f
1 parent 68d7a78
commit c204e6f
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Showing 8 changed files with 73 additions and 83 deletions.
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
@@ -41,6 +41,7 @@
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.SQLException;
+import java.util.Optional;
 import java.util.Set;
 import java.util.function.Supplier;
 import javax.sql.DataSource;
@@ -68,8 +69,8 @@ public class JdbcCatalogSchema extends JdbcBaseSchema implements Wrapper {
 
   /** default schema name, lazily initialized. */
   @SuppressWarnings({"method.invocation.invalid", "Convert2MethodRef"})
-  private final Supplier<String> defaultSchemaName =
-      Suppliers.memoize(() -> computeDefaultSchemaName());
+  private final Supplier<Optional<String>> defaultSchemaName =
+      Suppliers.memoize(() -> Optional.ofNullable(computeDefaultSchemaName()));
 
   /** Creates a JdbcCatalogSchema. */
   public JdbcCatalogSchema(DataSource dataSource, SqlDialect dialect,
@@ -150,7 +151,7 @@ public static JdbcCatalogSchema create(
     return subSchemas;
   }
 
-  private String computeDefaultSchemaName() {
+  private @Nullable String computeDefaultSchemaName() {
     try (Connection connection = dataSource.getConnection()) {
       return connection.getSchema();
     } catch (SQLException e) {
@@ -160,7 +161,7 @@ private String computeDefaultSchemaName() {
 
   /** Returns the name of the default sub-schema. */
   public @Nullable String getDefaultSubSchemaName() {
-    return defaultSchemaName.get();
+    return defaultSchemaName.get().orElse(null);
   }
 
   /** Returns the data source. */

diff --git a/core/src/main/java/org/apache/calcite/adapter/jdbc/JdbcSchema.java b/core/src/main/java/org/apache/calcite/adapter/jdbc/JdbcSchema.java
@@ -34,6 +34,7 @@
 import org.apache.calcite.schema.Table;
 import org.apache.calcite.schema.Wrapper;
 import org.apache.calcite.schema.lookup.IgnoreCaseLookup;
+import org.apache.calcite.schema.lookup.LazyReference;
 import org.apache.calcite.schema.lookup.LikePattern;
 import org.apache.calcite.schema.lookup.Lookup;
 import org.apache.calcite.sql.SqlDialect;
@@ -47,7 +48,6 @@
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Ordering;
 
-import org.checkerframework.checker.initialization.qual.UnknownInitialization;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -88,7 +88,7 @@ public class JdbcSchema extends JdbcBaseSchema implements Schema, Wrapper {
   final @Nullable String schema;
   public final SqlDialect dialect;
   final JdbcConvention convention;
-  private final Lookup<Table> tables;
+  private final LazyReference<Lookup<Table>> tables = new LazyReference<>();
   private final Lookup<JdbcSchema> subSchemas = Lookup.empty();
 
   @Experimental
@@ -113,21 +113,6 @@ public JdbcSchema(DataSource dataSource, SqlDialect dialect,
     this.convention = convention;
     this.catalog = catalog;
     this.schema = schema;
-    @UnknownInitialization
-    JdbcSchema self = this;
-    this.tables = new IgnoreCaseLookup<Table>() {
-      @Override public @Nullable Table get(String name) {
-        try (Stream<MetaImpl.MetaTable> s = self.getMetaTableStream(name)) {
-          return s.findFirst().map(it -> jdbcTableMapper(it)).orElse(null);
-        }
-      }
-
-      @Override public Set<String> getNames(LikePattern pattern) {
-        try (Stream<MetaImpl.MetaTable> s = self.getMetaTableStream(pattern.pattern)) {
-          return s.map(it -> it.tableName).collect(Collectors.toSet());
-        }
-      }
-    };
   }
 
   public static JdbcSchema create(
@@ -229,7 +214,19 @@ public static DataSource dataSource(String url, @Nullable String driverClassName
   }
 
   @Override public Lookup<Table> tables() {
-    return tables;
+    return tables.getOrCompute(() -> new IgnoreCaseLookup<Table>() {
+      @Override public @Nullable Table get(String name) {
+        try (Stream<MetaImpl.MetaTable> s = getMetaTableStream(name)) {
+          return s.findFirst().map(it -> jdbcTableMapper(it)).orElse(null);
+        }
+      }
+
+      @Override public Set<String> getNames(LikePattern pattern) {
+        try (Stream<MetaImpl.MetaTable> s = getMetaTableStream(pattern.pattern)) {
+          return s.map(it -> it.tableName).collect(Collectors.toSet());
+        }
+      }
+    });
   }
 
   @Override public Lookup<? extends Schema> subSchemas() {

diff --git a/core/src/main/java/org/apache/calcite/jdbc/SimpleCalciteSchema.java b/core/src/main/java/org/apache/calcite/jdbc/SimpleCalciteSchema.java
@@ -30,7 +30,6 @@
 import com.google.common.collect.ImmutableSortedMap;
 import com.google.common.collect.ImmutableSortedSet;
 
-import org.checkerframework.checker.initialization.qual.UnderInitialization;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.util.Collection;
@@ -101,8 +100,7 @@ private SimpleCalciteSchema(@Nullable CalciteSchema parent,
     return null;
   }
 
-  @Override protected CalciteSchema createSubSchema(@UnderInitialization SimpleCalciteSchema this,
-      Schema schema, String name) {
+  @Override protected CalciteSchema createSubSchema(Schema schema, String name) {
     return new SimpleCalciteSchema(this, schema, name);
   }
 

diff --git a/core/src/main/java/org/apache/calcite/prepare/RelOptTableImpl.java b/core/src/main/java/org/apache/calcite/prepare/RelOptTableImpl.java
@@ -47,6 +47,7 @@
 import org.apache.calcite.schema.TemporalTable;
 import org.apache.calcite.schema.TranslatableTable;
 import org.apache.calcite.schema.Wrapper;
+import org.apache.calcite.schema.lookup.LazyReference;
 import org.apache.calcite.schema.lookup.LikePattern;
 import org.apache.calcite.schema.lookup.Lookup;
 import org.apache.calcite.sql.SqlAccessType;
@@ -60,7 +61,6 @@
 
 import com.google.common.collect.ImmutableList;
 
-import org.checkerframework.checker.initialization.qual.UnknownInitialization;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.util.AbstractList;
@@ -432,16 +432,13 @@ private static class MySchemaPlus implements SchemaPlus {
     private final @Nullable SchemaPlus parent;
     private final String name;
     private final Schema schema;
-    private final Lookup<? extends SchemaPlus> subSchemas;
+    private final LazyReference<Lookup<? extends SchemaPlus>> subSchemas = new LazyReference<>();
 
 
     MySchemaPlus(@Nullable SchemaPlus parent, String name, Schema schema) {
       this.parent = parent;
       this.name = name;
       this.schema = schema;
-      @UnknownInitialization
-      MySchemaPlus self = this;
-      this.subSchemas = schema.subSchemas().map((s, key) -> new MySchemaPlus(self, key, s));
     }
 
     public static MySchemaPlus create(Path path) {
@@ -463,8 +460,8 @@ public static MySchemaPlus create(Path path) {
       return name;
     }
 
-    @Deprecated @Override public @Nullable SchemaPlus getSubSchema(String name) {
-      return subSchemas.get(name);
+    @Override public @Nullable SchemaPlus getSubSchema(String name) {
+      return subSchemas().get(name);
     }
 
     @Override public SchemaPlus add(String name, Schema schema) {
@@ -517,7 +514,8 @@ public static MySchemaPlus create(Path path) {
     }
 
     @Override public Lookup<? extends SchemaPlus> subSchemas() {
-      return subSchemas;
+      return subSchemas.getOrCompute(
+          () -> schema.subSchemas().map((s, key) -> new MySchemaPlus(this, key, s)));
     }
 
     @Override public @Nullable Table getTable(String name) {

diff --git a/core/src/main/java/org/apache/calcite/schema/impl/AbstractSchema.java b/core/src/main/java/org/apache/calcite/schema/impl/AbstractSchema.java
@@ -26,13 +26,13 @@
 import org.apache.calcite.schema.Schemas;
 import org.apache.calcite.schema.Table;
 import org.apache.calcite.schema.lookup.CompatibilityLookup;
+import org.apache.calcite.schema.lookup.LazyReference;
 import org.apache.calcite.schema.lookup.Lookup;
 
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableMultimap;
 import com.google.common.collect.Multimap;
 
-import org.checkerframework.checker.initialization.qual.UnknownInitialization;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.util.Collection;
@@ -60,23 +60,17 @@
  */
 public class AbstractSchema implements Schema {
 
-  private Lookup<Table> tables = new CompatibilityLookup<>(this::getTable, this::getTableNames);
-  private Lookup<Schema> subSchemas =
-      new CompatibilityLookup<>(this::getSubSchema, this::getSubSchemaNames);
-
-  public AbstractSchema() {
-    @UnknownInitialization
-    AbstractSchema self = this;
-    tables = new CompatibilityLookup<>(self::getTable, self::getTableNames);
-    subSchemas = new CompatibilityLookup<>(self::getSubSchema, self::getSubSchemaNames);
-  }
+  private LazyReference<Lookup<Table>> tables = new LazyReference<>();
+  private LazyReference<Lookup<Schema>> subSchemas = new LazyReference<>();
 
   @Override public Lookup<Table> tables() {
-    return tables;
+    return tables.getOrCompute(
+        () -> new CompatibilityLookup<>(this::getTable, this::getTableNames));
   }
 
   @Override public Lookup<? extends Schema> subSchemas() {
-    return subSchemas;
+    return subSchemas.getOrCompute(
+        () -> new CompatibilityLookup<>(this::getSubSchema, this::getSubSchemaNames));
   }
 
   @Override public boolean isMutable() {

diff --git a/core/src/main/java/org/apache/calcite/schema/lookup/CachedLookup.java b/core/src/main/java/org/apache/calcite/schema/lookup/CachedLookup.java
@@ -21,6 +21,7 @@
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * This class can be used to make a snapshot of a lookups.
@@ -30,12 +31,11 @@
 public class CachedLookup<T> implements Lookup<T> {
 
   private final Lookup<T> delegate;
-  private volatile Lookup<T> cachedDelegate;
+  private AtomicReference<Lookup<T>> cachedDelegate = new AtomicReference<>();
   private boolean enabled = true;
 
   public CachedLookup(Lookup<T> delegate) {
     this.delegate = delegate;
-    this.cachedDelegate = null;
   }
 
   @Override public @Nullable T get(final String name) {
@@ -54,26 +54,28 @@ private Lookup<T> delegate() {
     if (!enabled) {
       return delegate;
     }
-    if (cachedDelegate == null) {
-      synchronized (this) {
-        if (cachedDelegate == null) {
-          NameMap<T> map = new NameMap<>();
-          for (String name : delegate.getNames(LikePattern.any())) {
-            T entry = delegate.get(name);
-            if (entry != null) {
-              map.put(name, delegate.get(name));
-            }
-          }
-          cachedDelegate = new NameMapLookup<>(map);
+    while (true) {
+      Lookup<T> cached = cachedDelegate.get();
+      if (cached != null) {
+        return cached;
+      }
+      NameMap<T> map = new NameMap<>();
+      for (String name : delegate.getNames(LikePattern.any())) {
+        T entry = delegate.get(name);
+        if (entry != null) {
+          map.put(name, delegate.get(name));
         }
       }
+      cached = new NameMapLookup<>(map);
+      if (cachedDelegate.compareAndSet(null, cached)) {
+        return cached;
+      }
     }
-    return cachedDelegate;
   }
 
   public void enable(boolean enabled) {
     if (!enabled) {
-      cachedDelegate = null;
+      cachedDelegate.set(null);
     }
     this.enabled = enabled;
   }

diff --git a/core/src/main/java/org/apache/calcite/schema/lookup/IgnoreCaseLookup.java b/core/src/main/java/org/apache/calcite/schema/lookup/IgnoreCaseLookup.java
@@ -30,10 +30,7 @@
  */
 public abstract class IgnoreCaseLookup<T> implements Lookup<T> {
 
-  private volatile NameMap<String> nameMap = null;
-
-  public IgnoreCaseLookup() {
-  }
+  private LazyReference<NameMap<String>> nameMap = new LazyReference<>();
 
   /**
    * Returns a named entity with a given name, or null if not found.
@@ -50,31 +47,30 @@ public IgnoreCaseLookup() {
    * @return Entity, or null
    */
   @Override @Nullable public Named<T> getIgnoreCase(String name) {
-    Map.Entry<String, String> entry = getNameMap(false).range(name, false).firstEntry();
-    if (entry == null) {
-      entry = getNameMap(true).range(name, false).firstEntry();
-      if (entry == null) {
+    int retryCounter = 0;
+    while (true) {
+      Map.Entry<String, String> entry = nameMap.getOrCompute(this::loadNames)
+          .range(name, false)
+          .firstEntry();
+      if (entry != null) {
+        T result = get(entry.getValue());
+        return result == null ? null : new Named<>(entry.getKey(), result);
+      }
+      retryCounter++;
+      if (retryCounter > 1) {
         return null;
       }
+      nameMap.reset();
     }
-    T result = get(entry.getValue());
-    return result == null ? null : new Named<>(entry.getKey(), result);
   }
 
   @Override public abstract Set<String> getNames(LikePattern pattern);
 
-  private NameMap<String> getNameMap(boolean forceReload) {
-    if (nameMap == null || forceReload) {
-      synchronized (this) {
-        if (nameMap == null || forceReload) {
-          NameMap<String> tmp = new NameMap<>();
-          for (String name : getNames(LikePattern.any())) {
-            tmp.put(name, name);
-          }
-          nameMap = tmp;
-        }
-      }
+  private NameMap<String> loadNames() {
+    NameMap<String> result = new NameMap<>();
+    for (String name : getNames(LikePattern.any())) {
+      result.put(name, name);
     }
-    return nameMap;
+    return result;
   }
 }
diff --git a/core/src/main/java/org/apache/calcite/schema/lookup/LazyReference.java b/core/src/main/java/org/apache/calcite/schema/lookup/LazyReference.java
@@ -40,4 +40,8 @@ public T getOrCompute(Supplier<T> supplier) {
       }
     }
   }
+
+  public void reset() {
+    value.set(null);
+  }
 }
-Original file line number
+Diff line change
@@ Expand Up / @@ -40,4 +40,8 @@ public T getOrCompute(Supplier<T> supplier) { @@
           }
         }
       }
+      public void reset() {
+        value.set(null);
+      }
     }