feat: Support Describe message for DDL statements and other no-result…

… statements (#501)

* refactor: use analyze to get statement params

* feat: use analyze to describe statements

* fix: get param index from param name instead of index in list

* test: add more tests

* test: add more tests + disable clirr

Disabling clirr as it only adds noise, and somehow refuses to pick up
the latest ignore.

* chore: cleanup

* fix: update test for analyzeUpdate

* fix: disable flaky assertion

* fix: remove accidentally committed folder

* fix: remove more assertions pending node-postgres 8.9

* fix: disable more assertions awaiting 8.9

* cleanup: remove 'guess types' feature

Guessing the type of a parameter is no longer needed with backend
parameter type inferring support.

Fixes #487

* feat: support DML RETURNING clause

Add support for DML statements with a RETURNING clause.

* chore: remove unnecessary change

* feat: support Describe for non-query and DML statements

* test: describe DDL statements

src/main/java/com/google/cloud/spanner/pgadapter/metadata/DescribeResult.java

@@ -21,19 +21,20 @@
 import com.google.cloud.spanner.pgadapter.parsers.Parser;
 import com.google.spanner.v1.StructType;
 import java.util.Arrays;
+import javax.annotation.Nullable;
 
 @InternalApi
 public class DescribeResult {
-  private final ResultSet resultSet;
+  @Nullable private final ResultSet resultSet;
   private final int[] parameters;
 
-  public DescribeResult(int[] givenParameterTypes, ResultSet resultMetadata) {
+  public DescribeResult(int[] givenParameterTypes, @Nullable ResultSet resultMetadata) {
     this.resultSet = resultMetadata;
     this.parameters = extractParameters(givenParameterTypes, resultMetadata);
   }
 
-  static int[] extractParameters(int[] givenParameterTypes, ResultSet resultSet) {
-    if (!resultSet.getMetadata().hasUndeclaredParameters()) {
+  static int[] extractParameters(int[] givenParameterTypes, @Nullable ResultSet resultSet) {
+    if (resultSet == null || !resultSet.getMetadata().hasUndeclaredParameters()) {
       return givenParameterTypes;
     }
     return extractParameterTypes(
@@ -79,7 +80,7 @@ public int[] getParameters() {
     return parameters;
   }
 
-  public ResultSet getResultSet() {
+  public @Nullable ResultSet getResultSet() {
     return resultSet;
   }
 }

src/main/java/com/google/cloud/spanner/pgadapter/statements/BackendConnection.java

@@ -237,7 +237,11 @@ void execute() {
         } else if (statement.getSql().isEmpty()) {
           result.set(NO_RESULT);
         } else if (parsedStatement.isDdl()) {
-          result.set(ddlExecutor.execute(parsedStatement, statement));
+          if (analyze) {
+            result.set(NO_RESULT);
+          } else {
+            result.set(ddlExecutor.execute(parsedStatement, statement));
+          }
         } else {
           // Potentially replace pg_catalog table references with common table expressions.
           updatedStatement =
@@ -302,8 +306,10 @@ StatementResult bindAndExecute(Statement statement) {
           } else {
             resultSet = spannerConnection.analyzeUpdateStatement(statement, QueryAnalyzeMode.PLAN);
           }
-        } else {
+        } else if (parsedStatement.isQuery() || parsedStatement.hasReturningClause()) {
           resultSet = spannerConnection.analyzeQuery(statement, QueryAnalyzeMode.PLAN);
+        } else {
+          return NO_RESULT;
         }
         return new QueryResult(resultSet);
       }

src/main/java/com/google/cloud/spanner/pgadapter/statements/IntermediatePreparedStatement.java

@@ -18,6 +18,7 @@
 import com.google.cloud.spanner.Statement;
 import com.google.cloud.spanner.connection.AbstractStatementParser.ParsedStatement;
 import com.google.cloud.spanner.connection.StatementResult;
+import com.google.cloud.spanner.connection.StatementResult.ResultType;
 import com.google.cloud.spanner.pgadapter.ConnectionHandler;
 import com.google.cloud.spanner.pgadapter.error.PGExceptionFactory;
 import com.google.cloud.spanner.pgadapter.metadata.DescribeResult;
@@ -102,7 +103,12 @@ public Future<StatementResult> describeAsync(BackendConnection backendConnection
     this.describeResult =
         Futures.lazyTransform(
             statementResultFuture,
-            result -> new DescribeResult(this.givenParameterDataTypes, result.getResultSet()));
+            result ->
+                new DescribeResult(
+                    this.givenParameterDataTypes,
+                    result.getResultType() == ResultType.RESULT_SET
+                        ? result.getResultSet()
+                        : null));
     this.described = true;
     return statementResultFuture;
   }

src/main/java/com/google/cloud/spanner/pgadapter/statements/IntermediateStatement.java

@@ -26,6 +26,7 @@
 import com.google.cloud.spanner.connection.Connection;
 import com.google.cloud.spanner.connection.PostgreSQLStatementParser;
 import com.google.cloud.spanner.connection.StatementResult;
+import com.google.cloud.spanner.connection.StatementResult.ClientSideStatementType;
 import com.google.cloud.spanner.connection.StatementResult.ResultType;
 import com.google.cloud.spanner.pgadapter.ConnectionHandler;
 import com.google.cloud.spanner.pgadapter.error.PGException;
@@ -138,6 +139,9 @@ public void close() throws Exception {
   /** @return True if this is a select statement, false otherwise. */
   public boolean containsResultSet() {
     return this.parsedStatement.isQuery()
+        || (this.parsedStatement.getType() == StatementType.CLIENT_SIDE
+            && this.parsedStatement.getClientSideStatementType()
+                == ClientSideStatementType.RUN_BATCH)
         || (this.parsedStatement.isUpdate() && this.parsedStatement.hasReturningClause());
   }
 
@@ -169,7 +173,8 @@ public long getUpdateCount(ResultNotReadyBehavior resultNotReadyBehavior) {
       case QUERY:
         return -1L;
       case UPDATE:
-        return this.statementResult.getUpdateCount();
+        long res = this.statementResult.getUpdateCount();
+        return Math.max(res, 0L);
       case CLIENT_SIDE:
       case DDL:
       case UNKNOWN:

src/test/java/com/google/cloud/spanner/pgadapter/JdbcMockServerTest.java

@@ -648,6 +648,43 @@ public void testAutoDescribedStatementsAreReused() throws SQLException {
     }
   }
 
+  @Test
+  public void testDescribeDdlStatement() throws SQLException {
+    try (Connection connection = DriverManager.getConnection(createUrl())) {
+      try (PreparedStatement preparedStatement =
+          connection.prepareStatement("create table foo (id bigint primary key, value varchar)")) {
+        ParameterMetaData parameterMetaData = preparedStatement.getParameterMetaData();
+        assertEquals(0, parameterMetaData.getParameterCount());
+        assertNull(preparedStatement.getMetaData());
+      }
+    }
+  }
+
+  @Test
+  public void testDescribeClientSideNoResultStatement() throws SQLException {
+    try (Connection connection = DriverManager.getConnection(createUrl())) {
+      try (PreparedStatement preparedStatement = connection.prepareStatement("start batch dml")) {
+        ParameterMetaData parameterMetaData = preparedStatement.getParameterMetaData();
+        assertEquals(0, parameterMetaData.getParameterCount());
+        assertNull(preparedStatement.getMetaData());
+      }
+    }
+  }
+
+  @Test
+  public void testDescribeClientSideResultSetStatement() throws SQLException {
+    try (Connection connection = DriverManager.getConnection(createUrl())) {
+      try (PreparedStatement preparedStatement =
+          connection.prepareStatement("show statement_timeout")) {
+        SQLException exception =
+            assertThrows(SQLException.class, preparedStatement::getParameterMetaData);
+        assertEquals(
+            "ERROR: ResultSetMetadata are available only for results that were returned from Cloud Spanner",
+            exception.getMessage());
+      }
+    }
+  }
+
   @Test
   public void testMultipleQueriesInTransaction() throws SQLException {
     String sql = "SELECT 1";