refactor: remove code related to prepareReadWriteTransactions. (#3023)

* refactor: remove code related to prepareReadWriteTransactions.

* chore: remove beginTransactionAsync method.

Author: Arpan Mishra

java-spanner/google-cloud-spanner/clirr-ignored-differences.xml

@@ -20,6 +20,12 @@
     <differenceType>8001</differenceType>
     <className>com/google/cloud/spanner/connection/StatementParser</className>
   </difference>
+  <!-- (Remove since prepareReadWriteTransaction() has no usage. Session interface is annotated as internal API) -->
+  <difference>
+    <differenceType>7002</differenceType>
+    <className>com/google/cloud/spanner/Session</className>
+    <method>void prepareReadWriteTransaction()</method>
+  </difference>
   <difference>
     <differenceType>7002</differenceType>
     <className>com/google/cloud/spanner/SpannerOptions</className>

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

@@ -18,7 +18,6 @@
 
 import com.google.api.core.ApiFuture;
 import com.google.api.core.InternalApi;
-import com.google.cloud.spanner.Options.TransactionOption;
 import com.google.protobuf.Empty;
 
 /**
@@ -48,16 +47,6 @@ public interface Session extends DatabaseClient, AutoCloseable {
   /** Returns the resource name associated with this session. */
   String getName();
 
-  /**
-   * Prepares a transaction for use by a subsequent {@link
-   * DatabaseClient#readWriteTransaction(TransactionOption...)} or {@link #write(Iterable)} call. It
-   * is not necessary to call this method before running a transaction or performing a write, but
-   * doing so may allow one round trip of the protocol to be performed in advance; calling this
-   * method on an idle session that is expected to execute a transaction or write in the near future
-   * may reduce the latency of the subsequent transaction/write.
-   */
-  void prepareReadWriteTransaction();
-
   @Override
   void close();
 

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

@@ -100,7 +100,6 @@ interface SessionTransaction {
   private final String name;
   private final DatabaseId databaseId;
   private SessionTransaction activeTransaction;
-  ByteString readyTransactionId;
   private final Map<SpannerRpc.Option, ?> options;
   private volatile Instant lastUseTime;
   @Nullable private final Instant createTime;
@@ -378,12 +377,6 @@ public AsyncTransactionManagerImpl transactionManagerAsync(TransactionOption...
     return new AsyncTransactionManagerImpl(this, currentSpan, options);
   }
 
-  @Override
-  public void prepareReadWriteTransaction() {
-    setActive(null);
-    readyTransactionId = beginTransaction(true);
-  }
-
   @Override
   public ApiFuture<Empty> asyncClose() {
     return spanner.getRpc().asyncDeleteSession(name, options);
@@ -402,20 +395,6 @@ public void close() {
     }
   }
 
-  ByteString beginTransaction(boolean routeToLeader) {
-    try {
-      return beginTransactionAsync(routeToLeader).get();
-    } catch (ExecutionException e) {
-      throw SpannerExceptionFactory.newSpannerException(e.getCause() == null ? e : e.getCause());
-    } catch (InterruptedException e) {
-      throw SpannerExceptionFactory.propagateInterrupt(e);
-    }
-  }
-
-  ApiFuture<ByteString> beginTransactionAsync(boolean routeToLeader) {
-    return beginTransactionAsync(Options.fromTransactionOptions(), routeToLeader);
-  }
-
   ApiFuture<ByteString> beginTransactionAsync(Options transactionOptions, boolean routeToLeader) {
     final SettableApiFuture<ByteString> res = SettableApiFuture.create();
     final ISpan span = tracer.spanBuilder(SpannerImpl.BEGIN_TRANSACTION);
@@ -463,7 +442,7 @@ TransactionContextImpl newTransaction(Options options) {
     return TransactionContextImpl.newBuilder()
         .setSession(this)
         .setOptions(options)
-        .setTransactionId(readyTransactionId)
+        .setTransactionId(null)
         .setOptions(options)
         .setTrackTransactionStarter(spanner.getOptions().isTrackTransactionStarter())
         .setRpc(spanner.getRpc())
@@ -484,17 +463,12 @@ <T extends SessionTransaction> T setActive(@Nullable T ctx) {
       activeTransaction.invalidate();
     }
     activeTransaction = ctx;
-    readyTransactionId = null;
     if (activeTransaction != null) {
       activeTransaction.setSpan(currentSpan);
     }
     return ctx;
   }
 
-  boolean hasReadyTransaction() {
-    return readyTransactionId != null;
-  }
-
   TraceWrapper getTracer() {
     return tracer;
   }

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

@@ -1363,11 +1363,6 @@ public String getName() {
       return get().getName();
     }
 
-    @Override
-    public void prepareReadWriteTransaction() {
-      get().prepareReadWriteTransaction();
-    }
-
     @Override
     public void close() {
       try {
@@ -1618,11 +1613,6 @@ public String getName() {
       return get().getName();
     }
 
-    @Override
-    public void prepareReadWriteTransaction() {
-      get().prepareReadWriteTransaction();
-    }
-
     @Override
     public void close() {
       try {
@@ -1901,12 +1891,6 @@ public String getName() {
       return delegate.getName();
     }
 
-    @Override
-    public void prepareReadWriteTransaction() {
-      markUsed();
-      delegate.prepareReadWriteTransaction();
-    }
-
     private void keepAlive() {
       markUsed();
       final ISpan previousSpan = delegate.getCurrentSpan();
@@ -2129,12 +2113,6 @@ public String getName() {
       return delegate.getName();
     }
 
-    @Override
-    public void prepareReadWriteTransaction() {
-      throw SpannerExceptionFactory.newSpannerException(
-          ErrorCode.UNIMPLEMENTED, "Unimplemented with Multiplexed Session");
-    }
-
     @Override
     public void close() {
       synchronized (lock) {

java-spanner/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionImplTest.java

@@ -375,20 +375,6 @@ public void singleUseContextClosesTransaction() {
     assertThat(e.getMessage()).contains("invalidated");
   }
 
-  @Test
-  public void prepareClosesOldSingleUseContext() {
-    ReadContext ctx = session.singleUse(TimestampBound.strong());
-
-    Mockito.when(rpc.beginTransaction(Mockito.any(), Mockito.eq(options), eq(false)))
-        .thenReturn(Transaction.newBuilder().setId(ByteString.copyFromUtf8("t1")).build());
-    session.prepareReadWriteTransaction();
-    IllegalStateException e =
-        assertThrows(
-            IllegalStateException.class,
-            () -> ctx.read("Dummy", KeySet.all(), Collections.singletonList("C")));
-    assertThat(e.getMessage()).contains("invalidated");
-  }
-
   private static ResultSetMetadata newMetadata(Type type) {
     return ResultSetMetadata.newBuilder().setRowType(type.toProto().getStructType()).build();
   }

java-spanner/google-cloud-spanner/src/test/java/com/google/cloud/spanner/SessionPoolStressTest.java

@@ -32,7 +32,6 @@
 import com.google.cloud.spanner.SessionPoolOptions.InactiveTransactionRemovalOptions;
 import com.google.cloud.spanner.spi.v1.SpannerRpc.Option;
 import com.google.common.util.concurrent.Uninterruptibles;
-import com.google.protobuf.ByteString;
 import com.google.protobuf.Empty;
 import io.opencensus.trace.Tracing;
 import io.opentelemetry.api.OpenTelemetry;
@@ -161,21 +160,6 @@ public ApiFuture<Empty> asyncClose() {
             }
             return ApiFutures.immediateFuture(Empty.getDefaultInstance());
           }
-
-          @Override
-          public void prepareReadWriteTransaction() {
-            if (random.nextInt(100) < 10) {
-              expireSession(this);
-              throw SpannerExceptionFactoryTest.newSessionNotFoundException(this.getName());
-            }
-            String name = this.getName();
-            synchronized (lock) {
-              if (sessions.put(name, true)) {
-                setFailed();
-              }
-              this.readyTransactionId = ByteString.copyFromUtf8("foo");
-            }
-          }
         };
     sessionIndex++;
     return session;
@@ -192,18 +176,9 @@ private void setupSession(final SessionImpl session, final ReadContext mockConte
     when(mockResult.next()).thenReturn(true);
   }
 
-  private void expireSession(Session session) {
-    String name = session.getName();
-    synchronized (lock) {
-      sessions.remove(name);
-      expiredSessions.add(name);
-    }
-  }
-
   private void resetTransaction(SessionImpl session) {
     String name = session.getName();
     synchronized (lock) {
-      session.readyTransactionId = null;
       sessions.put(name, false);
     }
   }

java-spanner/google-cloud-spanner/src/test/java/com/google/cloud/spanner/TransactionRunnerImplTest.java

@@ -304,14 +304,7 @@ public void inlineBegin() {
 
     SessionImpl session =
         new SessionImpl(
-            spanner, "projects/p/instances/i/databases/d/sessions/s", Collections.EMPTY_MAP) {
-          @Override
-          public void prepareReadWriteTransaction() {
-            // Using a prepared transaction is not allowed when the beginTransaction should be
-            // inlined with the first statement.
-            throw new IllegalStateException();
-          }
-        };
+            spanner, "projects/p/instances/i/databases/d/sessions/s", Collections.EMPTY_MAP) {};
     session.setCurrentSpan(new OpenTelemetrySpan(mock(io.opentelemetry.api.trace.Span.class)));
     TransactionRunnerImpl runner = new TransactionRunnerImpl(session);
     runner.setSpan(span);
@@ -342,9 +335,6 @@ private long[] batchDmlException(int status) {
             .setSpan(session.getTracer().getCurrentSpan())
             .build();
     when(session.newTransaction(Options.fromTransactionOptions())).thenReturn(transaction);
-    when(session.beginTransactionAsync(true))
-        .thenReturn(
-            ApiFutures.immediateFuture(ByteString.copyFromUtf8(UUID.randomUUID().toString())));
     when(session.getName()).thenReturn(SessionId.of("p", "i", "d", "test").getName());
     TransactionRunnerImpl runner = new TransactionRunnerImpl(session);
     runner.setSpan(span);