feat: [WIP] support read-committed isolation level

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

@@ -222,4 +222,24 @@
     <className>com/google/cloud/spanner/connection/Connection</className>
     <method>com.google.cloud.spanner.ResultSet analyzeUpdateStatement(com.google.cloud.spanner.Statement, com.google.cloud.spanner.ReadContext$QueryAnalyzeMode, com.google.cloud.spanner.Options$UpdateOption[])</method>
   </difference>
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/cloud/spanner/connection/Connection</className>
+    <method>com.google.cloud.spanner.connection.IsolationLevel getDefaultIsolationLevel()</method>
+  </difference>
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/cloud/spanner/connection/Connection</className>
+    <method>void setDefaultIsolationLevel(com.google.cloud.spanner.connection.IsolationLevel)</method>
+  </difference>
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/cloud/spanner/connection/Connection</className>
+    <method>com.google.cloud.spanner.connection.IsolationLevel getTransactionIsolationLevel()</method>
+  </difference>
+  <difference>
+    <differenceType>7012</differenceType>
+    <className>com/google/cloud/spanner/connection/Connection</className>
+    <method>void setTransactionIsolationLevel(com.google.cloud.spanner.connection.IsolationLevel)</method>
+  </difference>
 </differences>

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AbstractMultiUseTransaction.java

@@ -53,7 +53,7 @@ public boolean isActive() {
    * Check that the current transaction actually has a valid underlying transaction. If not, the
    * method will throw a {@link SpannerException}.
    */
-  abstract void checkValidTransaction();
+  abstract void checkValidTransaction(ParsedStatement statement);
 
   /** Returns the {@link ReadContext} that can be used for queries on this transaction. */
   abstract ReadContext getReadContext();
@@ -63,7 +63,7 @@ public ApiFuture<ResultSet> executeQueryAsync(
       final AnalyzeMode analyzeMode,
       final QueryOption... options) {
     Preconditions.checkArgument(statement.isQuery(), "Statement is not a query");
-    checkValidTransaction();
+    checkValidTransaction(statement);
     return executeStatementAsync(
         statement,
         () -> {

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ClientSideStatementValueConverters.java

@@ -401,6 +401,11 @@ public PgTransactionMode convert(String value) {
             .startsWith("isolation level serializable")) {
           currentIndex += "isolation level serializable".length();
           mode.setIsolationLevel(IsolationLevel.ISOLATION_LEVEL_SERIALIZABLE);
+        } else if (valueWithSingleSpaces
+            .substring(currentIndex)
+            .startsWith("isolation level read committed")) {
+          currentIndex += "isolation level read committed".length();
+          mode.setIsolationLevel(IsolationLevel.ISOLATION_LEVEL_READ_COMMITTED);
         } else if (valueWithSingleSpaces
             .substring(currentIndex)
             .startsWith("isolation level default")) {

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/Connection.java

@@ -200,6 +200,33 @@ public interface Connection extends AutoCloseable {
   /** @return <code>true</code> if this connection is in read-only mode */
   boolean isReadOnly();
 
+  /** Sets the default isolation level to use for new read/write transactions. */
+  default void setDefaultIsolationLevel(IsolationLevel isolationLevel) {
+    throw new UnsupportedOperationException();
+  }
+
+  /** Returns the default isolation level that is used for new read/write transactions. */
+  default IsolationLevel getDefaultIsolationLevel() {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * Sets the isolation level to use for current transaction. This method may only be called when in
+   * a transaction, and before the transaction is actually started, i.e. before any statements have
+   * been executed in the transaction.
+   */
+  default void setTransactionIsolationLevel(IsolationLevel isolationLevel) {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * @return the transaction isolation level of the current transaction. This method may only be
+   *     called when the connection is in a transaction.
+   */
+  default IsolationLevel getTransactionIsolationLevel() {
+    throw new UnsupportedOperationException();
+  }
+
   /**
    * Sets the duration the connection should wait before automatically aborting the execution of a
    * statement. The default is no timeout. Statement timeouts are applied all types of statements,

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionImpl.java

@@ -190,6 +190,8 @@ static UnitOfWorkType of(TransactionMode transactionMode) {
   private DatabaseClient dbClient;
   private boolean autocommit;
   private boolean readOnly;
+  private IsolationLevel defaultIsolationLevel = IsolationLevel.SERIALIZABLE;
+  private IsolationLevel transactionIsolationLevel = IsolationLevel.SERIALIZABLE;
   private boolean returnCommitStats;
 
   private UnitOfWork currentUnitOfWork = null;
@@ -230,6 +232,7 @@ static UnitOfWorkType of(TransactionMode transactionMode) {
     this.dbClient = spanner.getDatabaseClient(options.getDatabaseId());
     this.retryAbortsInternally = options.isRetryAbortsInternally();
     this.readOnly = options.isReadOnly();
+    this.defaultIsolationLevel = options.getDefaultIsolationLevel();
     this.autocommit = options.isAutocommit();
     this.queryOptions = this.queryOptions.toBuilder().mergeFrom(options.getQueryOptions()).build();
     this.rpcPriority = options.getRPCPriority();
@@ -256,6 +259,7 @@ static UnitOfWorkType of(TransactionMode transactionMode) {
     this.ddlClient = ddlClient;
     this.dbClient = dbClient;
     setReadOnly(options.isReadOnly());
+    setDefaultIsolationLevel(options.getDefaultIsolationLevel());
     setAutocommit(options.isAutocommit());
     setReturnCommitStats(options.isReturnCommitStats());
     setDefaultTransactionOptions();
@@ -398,23 +402,69 @@ private boolean internalIsAutocommit() {
 
   @Override
   public void setReadOnly(boolean readOnly) {
+    checkValidStateForChangingDefaultTransactionOptions("read-only");
+    this.readOnly = readOnly;
+    clearLastTransactionAndSetDefaultTransactionOptions();
+  }
+
+  @Override
+  public boolean isReadOnly() {
+    ConnectionPreconditions.checkState(!isClosed(), CLOSED_ERROR_MSG);
+    return this.readOnly;
+  }
+
+  @Override
+  public void setDefaultIsolationLevel(IsolationLevel defaultIsolationLevel) {
+    checkValidStateForChangingDefaultTransactionOptions("default isolation level");
+    checkSupportedIsolationLevel(Preconditions.checkNotNull(defaultIsolationLevel));
+    this.defaultIsolationLevel = defaultIsolationLevel;
+    clearLastTransactionAndSetDefaultTransactionOptions();
+  }
+
+  @Override
+  public IsolationLevel getDefaultIsolationLevel() {
+    ConnectionPreconditions.checkState(!isClosed(), CLOSED_ERROR_MSG);
+    return this.defaultIsolationLevel;
+  }
+
+  private void checkSupportedIsolationLevel(IsolationLevel isolationLevel) {
+    if (!(isolationLevel == IsolationLevel.READ_COMMITTED
+        || isolationLevel == IsolationLevel.SERIALIZABLE)) {
+      throw SpannerExceptionFactory.newSpannerException(
+          ErrorCode.INVALID_ARGUMENT,
+          String.format(
+              "Only isolation levels %s and %s are supported",
+              IsolationLevel.READ_COMMITTED, IsolationLevel.SERIALIZABLE));
+    }
+  }
+
+  private void checkValidStateForChangingDefaultTransactionOptions(String property) {
     ConnectionPreconditions.checkState(!isClosed(), CLOSED_ERROR_MSG);
-    ConnectionPreconditions.checkState(!isBatchActive(), "Cannot set read-only while in a batch");
     ConnectionPreconditions.checkState(
-        !isTransactionStarted(), "Cannot set read-only while a transaction is active");
+        !isBatchActive(), String.format("Cannot set %s while in a batch", property));
+    ConnectionPreconditions.checkState(
+        !isTransactionStarted(),
+        String.format("Cannot set %s while a transaction is active", property));
     ConnectionPreconditions.checkState(
         !(isAutocommit() && isInTransaction()),
-        "Cannot set read-only while in a temporary transaction");
+        String.format("Cannot set default %s in a temporary transaction", property));
     ConnectionPreconditions.checkState(
-        !transactionBeginMarked, "Cannot set read-only when a transaction has begun");
-    this.readOnly = readOnly;
-    clearLastTransactionAndSetDefaultTransactionOptions();
+        !transactionBeginMarked,
+        String.format("Cannot set %s when a transaction has begun", property));
   }
 
   @Override
-  public boolean isReadOnly() {
+  public void setTransactionIsolationLevel(IsolationLevel isolationLevel) {
+    checkValidStateForSetTransactionOption("isolation level");
+    checkSupportedIsolationLevel(Preconditions.checkNotNull(defaultIsolationLevel));
+    this.transactionBeginMarked = true;
+    this.transactionIsolationLevel = isolationLevel;
+  }
+
+  @Override
+  public IsolationLevel getTransactionIsolationLevel() {
     ConnectionPreconditions.checkState(!isClosed(), CLOSED_ERROR_MSG);
-    return this.readOnly;
+    return this.transactionIsolationLevel;
   }
 
   private void clearLastTransactionAndSetDefaultTransactionOptions() {
@@ -558,13 +608,7 @@ public TransactionMode getTransactionMode() {
   @Override
   public void setTransactionMode(TransactionMode transactionMode) {
     Preconditions.checkNotNull(transactionMode);
-    ConnectionPreconditions.checkState(!isClosed(), CLOSED_ERROR_MSG);
-    ConnectionPreconditions.checkState(
-        !isBatchActive(), "Cannot set transaction mode while in a batch");
-    ConnectionPreconditions.checkState(isInTransaction(), "This connection has no transaction");
-    ConnectionPreconditions.checkState(
-        !isTransactionStarted(),
-        "The transaction mode cannot be set after the transaction has started");
+    checkValidStateForSetTransactionOption("transaction mode");
     ConnectionPreconditions.checkState(
         !isReadOnly() || transactionMode == TransactionMode.READ_ONLY_TRANSACTION,
         "The transaction mode can only be READ_ONLY when the connection is in read_only mode");
@@ -582,13 +626,7 @@ public String getTransactionTag() {
 
   @Override
   public void setTransactionTag(String tag) {
-    ConnectionPreconditions.checkState(!isClosed(), CLOSED_ERROR_MSG);
-    ConnectionPreconditions.checkState(
-        !isBatchActive(), "Cannot set transaction tag while in a batch");
-    ConnectionPreconditions.checkState(isInTransaction(), "This connection has no transaction");
-    ConnectionPreconditions.checkState(
-        !isTransactionStarted(),
-        "The transaction tag cannot be set after the transaction has started");
+    checkValidStateForSetTransactionOption("transaction tag");
     ConnectionPreconditions.checkState(
         getTransactionMode() == TransactionMode.READ_WRITE_TRANSACTION,
         "Transaction tag can only be set for a read/write transaction");
@@ -597,6 +635,16 @@ public void setTransactionTag(String tag) {
     this.transactionTag = tag;
   }
 
+  private void checkValidStateForSetTransactionOption(String property) {
+    ConnectionPreconditions.checkState(!isClosed(), CLOSED_ERROR_MSG);
+    ConnectionPreconditions.checkState(
+        !isBatchActive(), String.format("Cannot set %s while in a batch", property));
+    ConnectionPreconditions.checkState(isInTransaction(), "This connection has no transaction");
+    ConnectionPreconditions.checkState(
+        !isTransactionStarted(),
+        String.format("The %s cannot be set after the transaction has started", property));
+  }
+
   @Override
   public String getStatementTag() {
     ConnectionPreconditions.checkState(!isClosed(), CLOSED_ERROR_MSG);
@@ -745,6 +793,7 @@ private void setDefaultTransactionOptions() {
               ? UnitOfWorkType.READ_ONLY_TRANSACTION
               : UnitOfWorkType.READ_WRITE_TRANSACTION;
       batchMode = BatchMode.NONE;
+      transactionIsolationLevel = defaultIsolationLevel;
       transactionTag = null;
     } else {
       popUnitOfWorkFromTransactionStack();
@@ -1301,6 +1350,7 @@ UnitOfWork createNewUnitOfWork() {
         case READ_WRITE_TRANSACTION:
           return ReadWriteTransaction.newBuilder()
               .setDatabaseClient(dbClient)
+              .setIsolationLevel(defaultIsolationLevel)
               .setRetryAbortsInternally(retryAbortsInternally)
               .setReturnCommitStats(returnCommitStats)
               .setTransactionRetryListeners(transactionRetryListeners)

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionOptions.java

@@ -158,6 +158,7 @@ public String[] getValidValues() {
   private static final boolean DEFAULT_USE_PLAIN_TEXT = false;
   static final boolean DEFAULT_AUTOCOMMIT = true;
   static final boolean DEFAULT_READONLY = false;
+  static final IsolationLevel DEFAULT_ISOLATION_LEVEL = IsolationLevel.SERIALIZABLE;
   static final boolean DEFAULT_RETRY_ABORTS_INTERNALLY = true;
   private static final String DEFAULT_CREDENTIALS = null;
   private static final String DEFAULT_OAUTH_TOKEN = null;
@@ -183,6 +184,8 @@ public String[] getValidValues() {
   public static final String AUTOCOMMIT_PROPERTY_NAME = "autocommit";
   /** Name of the 'readonly' connection property. */
   public static final String READONLY_PROPERTY_NAME = "readonly";
+  /** Name of the 'defaultIsolationLevel' connection property. */
+  public static final String DEFAULT_ISOLATION_LEVEL_PROPERTY_NAME = "defaultIsolationLevel";
   /** Name of the 'retry aborts internally' connection property. */
   public static final String RETRY_ABORTS_INTERNALLY_PROPERTY_NAME = "retryAbortsInternally";
   /** Name of the 'credentials' connection property. */
@@ -231,6 +234,11 @@ public String[] getValidValues() {
                       READONLY_PROPERTY_NAME,
                       "Should the connection start in read-only mode (true/false)",
                       DEFAULT_READONLY),
+                  ConnectionProperty.createStringProperty(
+                      DEFAULT_ISOLATION_LEVEL_PROPERTY_NAME,
+                      String.format(
+                          "The default isolation level to use for new transactions on this connection. Must be one of %s",
+                          IsolationLevel.getValidNames())),
                   ConnectionProperty.createBooleanProperty(
                       RETRY_ABORTS_INTERNALLY_PROPERTY_NAME,
                       "Should the connection automatically retry Aborted errors (true/false)",
@@ -547,6 +555,7 @@ public static Builder newBuilder() {
 
   private final boolean autocommit;
   private final boolean readOnly;
+  private final IsolationLevel defaultIsolationLevel;
   private final boolean retryAbortsInternally;
   private final List<StatementExecutionInterceptor> statementExecutionInterceptors;
   private final SpannerOptionsConfigurator configurator;
@@ -636,6 +645,7 @@ private ConnectionOptions(Builder builder) {
 
     this.autocommit = parseAutocommit(this.uri);
     this.readOnly = parseReadOnly(this.uri);
+    this.defaultIsolationLevel = parseDefaultIsolationLevel(this.uri);
     this.retryAbortsInternally = parseRetryAbortsInternally(this.uri);
     this.statementExecutionInterceptors =
         Collections.unmodifiableList(builder.statementExecutionInterceptors);
@@ -719,6 +729,20 @@ static boolean parseReadOnly(String uri) {
     return value != null ? Boolean.parseBoolean(value) : DEFAULT_READONLY;
   }
 
+  @VisibleForTesting
+  static @Nullable IsolationLevel parseDefaultIsolationLevel(String uri) {
+    String value = parseUriProperty(uri, DEFAULT_ISOLATION_LEVEL_PROPERTY_NAME);
+    try {
+      return value != null ? IsolationLevel.valueOf(value.toUpperCase()) : DEFAULT_ISOLATION_LEVEL;
+    } catch (IllegalArgumentException exception) {
+      throw SpannerExceptionFactory.newSpannerException(
+          ErrorCode.INVALID_ARGUMENT,
+          String.format(
+              "Invalid value for %s: %s\nValue must be one of %s",
+              DEFAULT_ISOLATION_LEVEL_PROPERTY_NAME, value, IsolationLevel.getValidNames()));
+    }
+  }
+
   @VisibleForTesting
   static boolean parseRetryAbortsInternally(String uri) {
     String value = parseUriProperty(uri, RETRY_ABORTS_INTERNALLY_PROPERTY_NAME);
@@ -1026,6 +1050,14 @@ public boolean isReadOnly() {
     return readOnly;
   }
 
+  /**
+   * The initial default {@link IsolationLevel} for connections created by this {@link
+   * ConnectionOptions}
+   */
+  public IsolationLevel getDefaultIsolationLevel() {
+    return defaultIsolationLevel;
+  }
+
   /**
    * The initial retryAbortsInternally value for connections created by this {@link
    * ConnectionOptions}

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionStatementExecutor.java

@@ -92,7 +92,7 @@ interface ConnectionStatementExecutor {
 
   StatementResult statementRollback();
 
-  StatementResult statementSetTransactionMode(TransactionMode mode);
+  StatementResult statementSetTransactionMode(PgTransactionMode mode);
 
   StatementResult statementSetPgTransactionMode(PgTransactionMode transactionMode);
 

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/ConnectionStatementExecutorImpl.java

@@ -367,9 +367,10 @@ public StatementResult statementRollback() {
   }
 
   @Override
-  public StatementResult statementSetTransactionMode(TransactionMode mode) {
-    getConnection().setTransactionMode(mode);
-    return noResult(SET_TRANSACTION_MODE);
+  public StatementResult statementSetTransactionMode(PgTransactionMode mode) {
+    return statementSetPgTransactionMode(mode);
+    //    getConnection().setTransactionMode(mode);
+    //    return noResult(SET_TRANSACTION_MODE);
   }
 
   @Override
@@ -386,6 +387,11 @@ public StatementResult statementSetPgTransactionMode(PgTransactionMode transacti
           // no-op
       }
     }
+    if (transactionMode.getIsolationLevel() != null) {
+      getConnection()
+          .setTransactionIsolationLevel(
+              transactionMode.getIsolationLevel().getSpannerIsolationLevel());
+    }
     return noResult(SET_TRANSACTION_MODE);
   }
 
@@ -404,12 +410,16 @@ public StatementResult statementSetPgSessionCharacteristicsTransactionMode(
           // no-op
       }
     }
+    if (transactionMode.getIsolationLevel() != null) {
+      getConnection()
+          .setDefaultIsolationLevel(transactionMode.getIsolationLevel().getSpannerIsolationLevel());
+    }
     return noResult(SET_TRANSACTION_MODE);
   }
 
   @Override
   public StatementResult statementSetPgDefaultTransactionIsolation(IsolationLevel isolationLevel) {
-    // no-op
+    getConnection().setDefaultIsolationLevel(isolationLevel.getSpannerIsolationLevel());
     return noResult(SET_DEFAULT_TRANSACTION_ISOLATION);
   }
 

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/FailedBatchUpdate.java

@@ -57,7 +57,7 @@ public void retry(AbortedException aborted) throws AbortedException {
         .invokeInterceptors(
             RUN_BATCH_STATEMENT, StatementExecutionStep.RETRY_STATEMENT, transaction);
     try {
-      transaction.getReadContext().batchUpdate(statements);
+      transaction.getTransactionContext().batchUpdate(statements);
     } catch (AbortedException e) {
       // Propagate abort to force a new retry.
       throw e;