Merge branch 'bakape-master'

.gitignore

@@ -1,2 +1,3 @@
 .envrc
-vendor/
+vendor/
+.vscode

benchmark_test.go

@@ -39,46 +39,60 @@ func BenchmarkConnect(b *testing.B) {
 }
 
 func BenchmarkExec(b *testing.B) {
-	conn, err := pgconn.Connect(context.Background(), os.Getenv("PGX_TEST_CONN_STRING"))
-	require.Nil(b, err)
-	defer closeConn(b, conn)
-
 	expectedValues := [][]byte{[]byte("hello"), []byte("42"), []byte("2019-01-01")}
+	benchmarks := []struct {
+		name string
+		ctx  context.Context
+	}{
+		// Using an empty context other than context.Background() to compare
+		// performance
+		{"background context", context.Background()},
+		{"empty context", context.TODO()},
+	}
 
-	b.ResetTimer()
+	for _, bm := range benchmarks {
+		bm := bm
+		b.Run(bm.name, func(b *testing.B) {
+			conn, err := pgconn.Connect(bm.ctx, os.Getenv("PGX_TEST_CONN_STRING"))
+			require.Nil(b, err)
+			defer closeConn(b, conn)
 
-	for i := 0; i < b.N; i++ {
-		mrr := conn.Exec(context.Background(), "select 'hello'::text as a, 42::int4 as b, '2019-01-01'::date")
+			b.ResetTimer()
 
-		for mrr.NextResult() {
-			rr := mrr.ResultReader()
+			for i := 0; i < b.N; i++ {
+				mrr := conn.Exec(bm.ctx, "select 'hello'::text as a, 42::int4 as b, '2019-01-01'::date")
 
-			rowCount := 0
-			for rr.NextRow() {
-				rowCount++
-				if len(rr.Values()) != len(expectedValues) {
-					b.Fatalf("unexpected number of values: %d", len(rr.Values()))
-				}
-				for i := range rr.Values() {
-					if !bytes.Equal(rr.Values()[i], expectedValues[i]) {
-						b.Fatalf("unexpected values: %s %s", rr.Values()[i], expectedValues[i])
+				for mrr.NextResult() {
+					rr := mrr.ResultReader()
+
+					rowCount := 0
+					for rr.NextRow() {
+						rowCount++
+						if len(rr.Values()) != len(expectedValues) {
+							b.Fatalf("unexpected number of values: %d", len(rr.Values()))
+						}
+						for i := range rr.Values() {
+							if !bytes.Equal(rr.Values()[i], expectedValues[i]) {
+								b.Fatalf("unexpected values: %s %s", rr.Values()[i], expectedValues[i])
+							}
+						}
+					}
+					_, err = rr.Close()
+
+					if err != nil {
+						b.Fatal(err)
+					}
+					if rowCount != 1 {
+						b.Fatalf("unexpected rowCount: %d", rowCount)
 					}
 				}
-			}
-			_, err = rr.Close()
 
-			if err != nil {
-				b.Fatal(err)
+				err := mrr.Close()
+				if err != nil {
+					b.Fatal(err)
+				}
 			}
-			if rowCount != 1 {
-				b.Fatalf("unexpected rowCount: %d", rowCount)
-			}
-		}
-
-		err := mrr.Close()
-		if err != nil {
-			b.Fatal(err)
-		}
+		})
 	}
 }
 
@@ -130,40 +144,55 @@ func BenchmarkExecPossibleToCancel(b *testing.B) {
 }
 
 func BenchmarkExecPrepared(b *testing.B) {
-	conn, err := pgconn.Connect(context.Background(), os.Getenv("PGX_TEST_CONN_STRING"))
-	require.Nil(b, err)
-	defer closeConn(b, conn)
-
-	_, err = conn.Prepare(context.Background(), "ps1", "select 'hello'::text as a, 42::int4 as b, '2019-01-01'::date", nil)
-	require.Nil(b, err)
-
 	expectedValues := [][]byte{[]byte("hello"), []byte("42"), []byte("2019-01-01")}
 
-	b.ResetTimer()
+	benchmarks := []struct {
+		name string
+		ctx  context.Context
+	}{
+		// Using an empty context other than context.Background() to compare
+		// performance
+		{"background context", context.Background()},
+		{"empty context", context.TODO()},
+	}
 
-	for i := 0; i < b.N; i++ {
-		rr := conn.ExecPrepared(context.Background(), "ps1", nil, nil, nil)
+	for _, bm := range benchmarks {
+		bm := bm
+		b.Run(bm.name, func(b *testing.B) {
+			conn, err := pgconn.Connect(bm.ctx, os.Getenv("PGX_TEST_CONN_STRING"))
+			require.Nil(b, err)
+			defer closeConn(b, conn)
 
-		rowCount := 0
-		for rr.NextRow() {
-			rowCount++
-			if len(rr.Values()) != len(expectedValues) {
-				b.Fatalf("unexpected number of values: %d", len(rr.Values()))
-			}
-			for i := range rr.Values() {
-				if !bytes.Equal(rr.Values()[i], expectedValues[i]) {
-					b.Fatalf("unexpected values: %s %s", rr.Values()[i], expectedValues[i])
+			_, err = conn.Prepare(bm.ctx, "ps1", "select 'hello'::text as a, 42::int4 as b, '2019-01-01'::date", nil)
+			require.Nil(b, err)
+
+			b.ResetTimer()
+
+			for i := 0; i < b.N; i++ {
+				rr := conn.ExecPrepared(bm.ctx, "ps1", nil, nil, nil)
+
+				rowCount := 0
+				for rr.NextRow() {
+					rowCount++
+					if len(rr.Values()) != len(expectedValues) {
+						b.Fatalf("unexpected number of values: %d", len(rr.Values()))
+					}
+					for i := range rr.Values() {
+						if !bytes.Equal(rr.Values()[i], expectedValues[i]) {
+							b.Fatalf("unexpected values: %s %s", rr.Values()[i], expectedValues[i])
+						}
+					}
+				}
+				_, err = rr.Close()
+
+				if err != nil {
+					b.Fatal(err)
+				}
+				if rowCount != 1 {
+					b.Fatalf("unexpected rowCount: %d", rowCount)
 				}
 			}
-		}
-		_, err = rr.Close()
-
-		if err != nil {
-			b.Fatal(err)
-		}
-		if rowCount != 1 {
-			b.Fatalf("unexpected rowCount: %d", rowCount)
-		}
+		})
 	}
 }
 

pgconn.go

@@ -362,13 +362,15 @@ func (pgConn *PgConn) SendBytes(ctx context.Context, buf []byte) error {
 	}
 	defer pgConn.unlock()
 
-	select {
-	case <-ctx.Done():
-		return &contextAlreadyDoneError{err: ctx.Err()}
-	default:
+	if ctx != context.Background() {
+		select {
+		case <-ctx.Done():
+			return &contextAlreadyDoneError{err: ctx.Err()}
+		default:
+		}
+		pgConn.contextWatcher.Watch(ctx)
+		defer pgConn.contextWatcher.Unwatch()
 	}
-	pgConn.contextWatcher.Watch(ctx)
-	defer pgConn.contextWatcher.Unwatch()
 
 	n, err := pgConn.conn.Write(buf)
 	if err != nil {
@@ -392,13 +394,15 @@ func (pgConn *PgConn) ReceiveMessage(ctx context.Context) (pgproto3.BackendMessa
 	}
 	defer pgConn.unlock()
 
-	select {
-	case <-ctx.Done():
-		return nil, &contextAlreadyDoneError{err: ctx.Err()}
-	default:
+	if ctx != context.Background() {
+		select {
+		case <-ctx.Done():
+			return nil, &contextAlreadyDoneError{err: ctx.Err()}
+		default:
+		}
+		pgConn.contextWatcher.Watch(ctx)
+		defer pgConn.contextWatcher.Unwatch()
 	}
-	pgConn.contextWatcher.Watch(ctx)
-	defer pgConn.contextWatcher.Unwatch()
 
 	msg, err := pgConn.receiveMessage()
 	if err != nil {
@@ -489,8 +493,10 @@ func (pgConn *PgConn) Close(ctx context.Context) error {
 
 	defer pgConn.conn.Close()
 
-	pgConn.contextWatcher.Watch(ctx)
-	defer pgConn.contextWatcher.Unwatch()
+	if ctx != context.Background() {
+		pgConn.contextWatcher.Watch(ctx)
+		defer pgConn.contextWatcher.Unwatch()
+	}
 
 	// Ignore any errors sending Terminate message and waiting for server to close connection.
 	// This mimics the behavior of libpq PQfinish. It calls closePGconn which calls sendTerminateConn which purposefully
@@ -600,13 +606,15 @@ func (pgConn *PgConn) Prepare(ctx context.Context, name, sql string, paramOIDs [
 	}
 	defer pgConn.unlock()
 
-	select {
-	case <-ctx.Done():
-		return nil, &contextAlreadyDoneError{err: ctx.Err()}
-	default:
+	if ctx != context.Background() {
+		select {
+		case <-ctx.Done():
+			return nil, &contextAlreadyDoneError{err: ctx.Err()}
+		default:
+		}
+		pgConn.contextWatcher.Watch(ctx)
+		defer pgConn.contextWatcher.Unwatch()
 	}
-	pgConn.contextWatcher.Watch(ctx)
-	defer pgConn.contextWatcher.Unwatch()
 
 	buf := pgConn.wbuf
 	buf = (&pgproto3.Parse{Name: name, Query: sql, ParameterOIDs: paramOIDs}).Encode(buf)
@@ -693,12 +701,14 @@ func (pgConn *PgConn) CancelRequest(ctx context.Context) error {
 	}
 	defer cancelConn.Close()
 
-	contextWatcher := ctxwatch.NewContextWatcher(
-		func() { cancelConn.SetDeadline(time.Date(1, 1, 1, 1, 1, 1, 1, time.UTC)) },
-		func() { cancelConn.SetDeadline(time.Time{}) },
-	)
-	contextWatcher.Watch(ctx)
-	defer contextWatcher.Unwatch()
+	if ctx != context.Background() {
+		contextWatcher := ctxwatch.NewContextWatcher(
+			func() { cancelConn.SetDeadline(time.Date(1, 1, 1, 1, 1, 1, 1, time.UTC)) },
+			func() { cancelConn.SetDeadline(time.Time{}) },
+		)
+		contextWatcher.Watch(ctx)
+		defer contextWatcher.Unwatch()
+	}
 
 	buf := make([]byte, 16)
 	binary.BigEndian.PutUint32(buf[0:4], 16)
@@ -726,14 +736,16 @@ func (pgConn *PgConn) WaitForNotification(ctx context.Context) error {
 	}
 	defer pgConn.unlock()
 
-	select {
-	case <-ctx.Done():
-		return ctx.Err()
-	default:
-	}
+	if ctx != context.Background() {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+		}
 
-	pgConn.contextWatcher.Watch(ctx)
-	defer pgConn.contextWatcher.Unwatch()
+		pgConn.contextWatcher.Watch(ctx)
+		defer pgConn.contextWatcher.Unwatch()
+	}
 
 	for {
 		msg, err := pgConn.receiveMessage()
@@ -766,16 +778,17 @@ func (pgConn *PgConn) Exec(ctx context.Context, sql string) *MultiResultReader {
 		ctx:    ctx,
 	}
 	multiResult := &pgConn.multiResultReader
-
-	select {
-	case <-ctx.Done():
-		multiResult.closed = true
-		multiResult.err = &contextAlreadyDoneError{err: ctx.Err()}
-		pgConn.unlock()
-		return multiResult
-	default:
+	if ctx != context.Background() {
+		select {
+		case <-ctx.Done():
+			multiResult.closed = true
+			multiResult.err = &contextAlreadyDoneError{err: ctx.Err()}
+			pgConn.unlock()
+			return multiResult
+		default:
+		}
+		pgConn.contextWatcher.Watch(ctx)
 	}
-	pgConn.contextWatcher.Watch(ctx)
 
 	buf := pgConn.wbuf
 	buf = (&pgproto3.Query{String: sql}).Encode(buf)
@@ -822,7 +835,7 @@ func (pgConn *PgConn) ExecParams(ctx context.Context, sql string, paramValues []
 	buf = (&pgproto3.Parse{Query: sql, ParameterOIDs: paramOIDs}).Encode(buf)
 	buf = (&pgproto3.Bind{ParameterFormatCodes: paramFormats, Parameters: paramValues, ResultFormatCodes: resultFormats}).Encode(buf)
 
-	pgConn.execExtendedSuffix(ctx, buf, result)
+	pgConn.execExtendedSuffix(buf, result)
 
 	return result
 }
@@ -848,7 +861,7 @@ func (pgConn *PgConn) ExecPrepared(ctx context.Context, stmtName string, paramVa
 	buf := pgConn.wbuf
 	buf = (&pgproto3.Bind{PreparedStatement: stmtName, ParameterFormatCodes: paramFormats, Parameters: paramValues, ResultFormatCodes: resultFormats}).Encode(buf)
 
-	pgConn.execExtendedSuffix(ctx, buf, result)
+	pgConn.execExtendedSuffix(buf, result)
 
 	return result
 }
@@ -873,20 +886,22 @@ func (pgConn *PgConn) execExtendedPrefix(ctx context.Context, paramValues [][]by
 		return result
 	}
 
-	select {
-	case <-ctx.Done():
-		result.concludeCommand(nil, &contextAlreadyDoneError{err: ctx.Err()})
-		result.closed = true
-		pgConn.unlock()
-		return result
-	default:
+	if ctx != context.Background() {
+		select {
+		case <-ctx.Done():
+			result.concludeCommand(nil, &contextAlreadyDoneError{err: ctx.Err()})
+			result.closed = true
+			pgConn.unlock()
+			return result
+		default:
+		}
+		pgConn.contextWatcher.Watch(ctx)
 	}
-	pgConn.contextWatcher.Watch(ctx)
 
 	return result
 }
 
-func (pgConn *PgConn) execExtendedSuffix(ctx context.Context, buf []byte, result *ResultReader) {
+func (pgConn *PgConn) execExtendedSuffix(buf []byte, result *ResultReader) {
 	buf = (&pgproto3.Describe{ObjectType: 'P'}).Encode(buf)
 	buf = (&pgproto3.Execute{}).Encode(buf)
 	buf = (&pgproto3.Sync{}).Encode(buf)
@@ -907,14 +922,16 @@ func (pgConn *PgConn) CopyTo(ctx context.Context, w io.Writer, sql string) (Comm
 		return nil, err
 	}
 
-	select {
-	case <-ctx.Done():
-		pgConn.unlock()
-		return nil, &contextAlreadyDoneError{err: ctx.Err()}
-	default:
+	if ctx != context.Background() {
+		select {
+		case <-ctx.Done():
+			pgConn.unlock()
+			return nil, &contextAlreadyDoneError{err: ctx.Err()}
+		default:
+		}
+		pgConn.contextWatcher.Watch(ctx)
+		defer pgConn.contextWatcher.Unwatch()
 	}
-	pgConn.contextWatcher.Watch(ctx)
-	defer pgConn.contextWatcher.Unwatch()
 
 	// Send copy to command
 	buf := pgConn.wbuf
@@ -966,13 +983,15 @@ func (pgConn *PgConn) CopyFrom(ctx context.Context, r io.Reader, sql string) (Co
 	}
 	defer pgConn.unlock()
 
-	select {
-	case <-ctx.Done():
-		return nil, &contextAlreadyDoneError{err: ctx.Err()}
-	default:
+	if ctx != context.Background() {
+		select {
+		case <-ctx.Done():
+			return nil, &contextAlreadyDoneError{err: ctx.Err()}
+		default:
+		}
+		pgConn.contextWatcher.Watch(ctx)
+		defer pgConn.contextWatcher.Unwatch()
 	}
-	pgConn.contextWatcher.Watch(ctx)
-	defer pgConn.contextWatcher.Unwatch()
 
 	// Send copy to command
 	buf := pgConn.wbuf
@@ -1359,15 +1378,17 @@ func (pgConn *PgConn) ExecBatch(ctx context.Context, batch *Batch) *MultiResultR
 	}
 	multiResult := &pgConn.multiResultReader
 
-	select {
-	case <-ctx.Done():
-		multiResult.closed = true
-		multiResult.err = &contextAlreadyDoneError{err: ctx.Err()}
-		pgConn.unlock()
-		return multiResult
-	default:
+	if ctx != context.Background() {
+		select {
+		case <-ctx.Done():
+			multiResult.closed = true
+			multiResult.err = &contextAlreadyDoneError{err: ctx.Err()}
+			pgConn.unlock()
+			return multiResult
+		default:
+		}
+		pgConn.contextWatcher.Watch(ctx)
 	}
-	pgConn.contextWatcher.Watch(ctx)
 
 	batch.buf = (&pgproto3.Sync{}).Encode(batch.buf)