Merge pull request #157037 from yuzefovich/blathers/backport-release-25.4-156959

release-25.4: copy: step txn unconditionally

Author: yuzefovich

pkg/sql/conn_executor.go

@@ -3219,6 +3219,12 @@ func (ex *connExecutor) execCopyIn(
 	// Disable the buffered writes for COPY since there is no benefit in this
 	// ability here.
 	ex.state.mu.txn.SetBufferedWritesEnabled(false /* enabled */)
+	// Step the txn in case it had just been rolled back to a savepoint (if it
+	// wasn't, this is harmless). This also matches what we do unconditionally
+	// on the main query path.
+	if err := ex.state.mu.txn.Step(ctx, false /* allowReadTimestampStep */); err != nil {
+		return ex.makeErrEvent(err, cmd.ParsedStmt.AST)
+	}
 	txnOpt := copyTxnOpt{
 		txn:           ex.state.mu.txn,
 		txnTimestamp:  ex.state.sqlTimestamp,

pkg/sql/copy/copy_in_test.go

@@ -648,49 +648,51 @@ func TestCopyTransaction(t *testing.T) {
 	s, db, _ := serverutils.StartServer(t, base.TestServerArgs{})
 	defer s.Stopper().Stop(context.Background())
 
-	if _, err := db.Exec(`
+	_, err := db.Exec(`
 		CREATE DATABASE d;
 		SET DATABASE = d;
 		CREATE TABLE t (
 			i INT PRIMARY KEY
 		);
-	`); err != nil {
-		t.Fatal(err)
-	}
+	`)
+	require.NoError(t, err)
 
 	txn, err := db.Begin()
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	// Note that, at least with lib/pq, this doesn't actually send a Parse msg
-	// (which we wouldn't support, as we don't support Copy-in in extended
-	// protocol mode). lib/pq has magic for recognizing a Copy.
-	stmt, err := txn.Prepare(pq.CopyIn("t", "i"))
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.NoError(t, err)
 
-	const val = 2
+	// Run COPY twice with the first one being rolled back via savepoints.
+	for val, doSavepoint := range []bool{true, false} {
+		func() {
+			if doSavepoint {
+				_, err = txn.Exec("SAVEPOINT s")
+				require.NoError(t, err)
+				defer func() {
+					_, err = txn.Exec("ROLLBACK TO SAVEPOINT s")
+					require.NoError(t, err)
+				}()
+			}
+			// Note that, at least with lib/pq, this doesn't actually send a
+			// Parse msg (which we wouldn't support, as we don't support Copy-in
+			// in extended protocol mode). lib/pq has magic for recognizing a
+			// Copy.
+			stmt, err := txn.Prepare(pq.CopyIn("t", "i"))
+			require.NoError(t, err)
 
-	_, err = stmt.Exec(val)
-	if err != nil {
-		t.Fatal(err)
-	}
+			_, err = stmt.Exec(val)
+			require.NoError(t, err)
 
-	if err = stmt.Close(); err != nil {
-		t.Fatal(err)
-	}
+			err = stmt.Close()
+			require.NoError(t, err)
 
-	var i int
-	if err := txn.QueryRow("SELECT i FROM d.t").Scan(&i); err != nil {
-		t.Fatal(err)
-	} else if i != val {
-		t.Fatalf("expected 1, got %d", i)
-	}
-	if err := txn.Commit(); err != nil {
-		t.Fatal(err)
+			var i int
+			err = txn.QueryRow("SELECT i FROM d.t").Scan(&i)
+			require.NoError(t, err)
+			if i != val {
+				t.Fatalf("expected %d, got %d", val, i)
+			}
+		}()
 	}
+	require.NoError(t, txn.Commit())
 }
 
 // TestCopyFromFKCheck verifies that foreign keys are checked during COPY.

pkg/sql/copy/copy_out_test.go

@@ -62,14 +62,26 @@ func TestCopyOutTransaction(t *testing.T) {
 	tx, err := conn.Begin(ctx)
 	require.NoError(t, err)
 
-	_, err = tx.Exec(ctx, "INSERT INTO t VALUES (1)")
-	require.NoError(t, err)
+	for val, doSavepoint := range []bool{true, false} {
+		func() {
+			if doSavepoint {
+				_, err = tx.Exec(ctx, "SAVEPOINT s")
+				require.NoError(t, err)
+				defer func() {
+					_, err = tx.Exec(ctx, "ROLLBACK TO SAVEPOINT s")
+					require.NoError(t, err)
+				}()
+			}
 
-	var buf bytes.Buffer
-	_, err = tx.Conn().PgConn().CopyTo(ctx, &buf, "COPY t TO STDOUT")
-	require.NoError(t, err)
-	require.Equal(t, "1\n", buf.String())
+			_, err = tx.Exec(ctx, "INSERT INTO t VALUES ($1)", val)
+			require.NoError(t, err)
 
+			var buf bytes.Buffer
+			_, err = tx.Conn().PgConn().CopyTo(ctx, &buf, "COPY t TO STDOUT")
+			require.NoError(t, err)
+			require.Equal(t, fmt.Sprintf("%d\n", val), buf.String())
+		}()
+	}
 	require.NoError(t, tx.Rollback(ctx))
 }
 

pkg/sql/internal.go

@@ -1471,15 +1471,17 @@ func (ie *InternalExecutor) commitTxn(ctx context.Context) error {
 	return ex.commitSQLTransactionInternal(ctx)
 }
 
-// checkIfStmtIsAllowed returns an error if the internal executor is not bound
-// with the outer-txn-related info but is used to run DDL statements within an
-// outer txn.
-// TODO (janexing): this will be deprecate soon since it's not a good idea
-// to have `extraTxnState` to store the info from a outer txn.
+// checkIfStmtIsAllowed returns an error if the internal executor cannot execute
+// the given stmt.
 func (ie *InternalExecutor) checkIfStmtIsAllowed(stmt tree.Statement, txn *kv.Txn) error {
 	if stmt == nil {
 		return nil
 	}
+	if _, ok := stmt.(*tree.CopyFrom); ok {
+		// COPY FROM has special handling in the connExecutor, so we can't run
+		// it via the internal executor.
+		return errors.New("COPY cannot be run via the internal executor")
+	}
 	if tree.CanModifySchema(stmt) && txn != nil && ie.extraTxnState == nil {
 		return errors.New("DDL statement is disallowed if internal " +
 			"executor is not bound with txn metadata")

pkg/sql/opt/exec/execbuilder/testdata/execute_internally_builtin

@@ -298,3 +298,6 @@ subtest end
 # Regression test for crashing with SHOW COMMIT TIMESTAMP.
 statement error this statement is disallowed
 SELECT crdb_internal.execute_internally('SHOW COMMIT TIMESTAMP;', true);
+
+statement error COPY cannot be run via the internal executor
+SELECT crdb_internal.execute_internally('COPY t FROM STDIN');