Create staementfactory on-demand

Author: sakthivelmanii

google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseClient.java

@@ -617,6 +617,6 @@ ServerStream<BatchWriteResponse> batchWriteAtLeastOnce(
    * <p>databaseClient.newStatementFactory().of("SELECT NAME FROM TABLE WHERE ID = ?", 10)
    */
   default StatementFactory newStatementFactory() {
-    return new StatementFactory(getDialect());
+    throw new UnsupportedOperationException("method should be overwritten");
   }
 }

google-cloud-spanner/src/main/java/com/google/cloud/spanner/DatabaseClientImpl.java

@@ -22,11 +22,16 @@
 import com.google.cloud.spanner.Options.UpdateOption;
 import com.google.cloud.spanner.SessionPool.PooledSessionFuture;
 import com.google.cloud.spanner.SpannerImpl.ClosedException;
+import com.google.cloud.spanner.Statement.StatementFactory;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Function;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.spanner.v1.BatchWriteResponse;
 import io.opentelemetry.api.common.Attributes;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 import javax.annotation.Nullable;
 
 class DatabaseClientImpl implements DatabaseClient {
@@ -41,6 +46,8 @@ class DatabaseClientImpl implements DatabaseClient {
   @VisibleForTesting final boolean useMultiplexedSessionPartitionedOps;
   @VisibleForTesting final boolean useMultiplexedSessionForRW;
 
+  private StatementFactory statementFactory = null;
+
   final boolean useMultiplexedSessionBlindWrite;
 
   @VisibleForTesting
@@ -139,6 +146,21 @@ public Dialect getDialect() {
     return pool.getDialect();
   }
 
+  @Override
+  public StatementFactory newStatementFactory() {
+    if (statementFactory == null) {
+      try {
+        Dialect dialect = getDialectAsync().get(5, TimeUnit.SECONDS);
+        statementFactory = new StatementFactory(dialect);
+      } catch (ExecutionException | TimeoutException e) {
+        throw SpannerExceptionFactory.asSpannerException(e);
+      } catch (InterruptedException e) {
+        throw SpannerExceptionFactory.propagateInterrupt(e);
+      }
+    }
+    return statementFactory;
+  }
+
   @Override
   @Nullable
   public String getDatabaseRole() {
@@ -346,6 +368,14 @@ public long executePartitionedUpdate(final Statement stmt, final UpdateOption...
     return executePartitionedUpdateWithPooledSession(stmt, options);
   }
 
+  private Future<Dialect> getDialectAsync() {
+    MultiplexedSessionDatabaseClient client = getMultiplexedSessionDatabaseClient();
+    if (client != null) {
+      return client.getDialectAsync();
+    }
+    return pool.getDialectAsync();
+  }
+
   private long executePartitionedUpdateWithPooledSession(
       final Statement stmt, final UpdateOption... options) {
     ISpan span = tracer.spanBuilder(PARTITION_DML_TRANSACTION, commonAttributes);

google-cloud-spanner/src/main/java/com/google/cloud/spanner/MultiplexedSessionDatabaseClient.java

@@ -44,6 +44,7 @@
 import java.util.Map;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
@@ -652,6 +653,14 @@ public Dialect getDialect() {
     }
   }
 
+  public Future<Dialect> getDialectAsync() {
+    try {
+      return MAINTAINER_SERVICE.submit(dialectSupplier::get);
+    } catch (Exception exception) {
+      throw SpannerExceptionFactory.asSpannerException(exception);
+    }
+  }
+
   @Override
   public Timestamp write(Iterable<Mutation> mutations) throws SpannerException {
     return createMultiplexedSessionTransaction(/* singleUse = */ false).write(mutations);

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPool.java

@@ -104,6 +104,7 @@
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
@@ -2548,6 +2549,10 @@ Dialect getDialect() {
     }
   }
 
+  Future<Dialect> getDialectAsync() {
+    return executor.submit(this::getDialect);
+  }
+
   PooledSessionReplacementHandler getPooledSessionReplacementHandler() {
     return pooledSessionReplacementHandler;
   }