diff --git a/pgconn/pgconn.go b/pgconn/pgconn.go
index 512c9a88..c785f367 100644
--- a/pgconn/pgconn.go
+++ b/pgconn/pgconn.go
@@ -404,19 +404,6 @@ func (pgConn *PgConn) IsAlive() bool {
 	return !pgConn.closed
 }
 
-// writeAll writes the entire buffer. The connection is hard closed on a partial write or a non-temporary error.
-func (pgConn *PgConn) writeAll(buf []byte) error {
-	n, err := pgConn.conn.Write(buf)
-	if err != nil {
-		if n > 0 {
-			pgConn.hardClose()
-		} else if ne, ok := err.(net.Error); ok && !ne.Temporary() {
-			pgConn.hardClose()
-		}
-	}
-	return err
-}
-
 // ParameterStatus returns the value of a parameter reported by the server (e.g.
 // server_version). Returns an empty string for unknown parameters.
 func (pgConn *PgConn) ParameterStatus(key string) string {
@@ -501,8 +488,9 @@ func (pgConn *PgConn) Prepare(ctx context.Context, name, sql string, paramOIDs [
 	buf = (&pgproto3.Describe{ObjectType: 'S', Name: name}).Encode(buf)
 	buf = (&pgproto3.Sync{}).Encode(buf)
 
-	err := pgConn.writeAll(buf)
+	_, err := pgConn.conn.Write(buf)
 	if err != nil {
+		pgConn.hardClose()
 		return nil, preferContextOverNetTimeoutError(ctx, err)
 	}
 
@@ -666,8 +654,9 @@ func (pgConn *PgConn) Exec(ctx context.Context, sql string) *MultiResultReader {
 	var buf []byte
 	buf = (&pgproto3.Query{String: sql}).Encode(buf)
 
-	err := pgConn.writeAll(buf)
+	_, err := pgConn.conn.Write(buf)
 	if err != nil {
+		pgConn.hardClose()
 		multiResult.cleanupContextDeadline()
 		multiResult.closed = true
 		multiResult.err = preferContextOverNetTimeoutError(ctx, err)
@@ -723,8 +712,9 @@ func (pgConn *PgConn) ExecParams(ctx context.Context, sql string, paramValues []
 	buf = (&pgproto3.Execute{}).Encode(buf)
 	buf = (&pgproto3.Sync{}).Encode(buf)
 
-	err := pgConn.writeAll(buf)
+	_, err := pgConn.conn.Write(buf)
 	if err != nil {
+		pgConn.hardClose()
 		result.concludeCommand("", err)
 		result.cleanupContextDeadline()
 		result.closed = true
@@ -768,8 +758,9 @@ func (pgConn *PgConn) ExecPrepared(ctx context.Context, stmtName string, paramVa
 	buf = (&pgproto3.Execute{}).Encode(buf)
 	buf = (&pgproto3.Sync{}).Encode(buf)
 
-	err := pgConn.writeAll(buf)
+	_, err := pgConn.conn.Write(buf)
 	if err != nil {
+		pgConn.hardClose()
 		result.concludeCommand("", err)
 		result.cleanupContextDeadline()
 		result.closed = true
@@ -792,8 +783,9 @@ func (pgConn *PgConn) CopyTo(ctx context.Context, w io.Writer, sql string) (Comm
 	var buf []byte
 	buf = (&pgproto3.Query{String: sql}).Encode(buf)
 
-	err := pgConn.writeAll(buf)
+	_, err := pgConn.conn.Write(buf)
 	if err != nil {
+		pgConn.hardClose()
 		cleanupContextDeadline()
 		<-pgConn.controller
 
@@ -853,8 +845,9 @@ func (pgConn *PgConn) CopyFrom(ctx context.Context, r io.Reader, sql string) (Co
 	var buf []byte
 	buf = (&pgproto3.Query{String: sql}).Encode(buf)
 
-	err := pgConn.writeAll(buf)
+	_, err := pgConn.conn.Write(buf)
 	if err != nil {
+		pgConn.hardClose()
 		cleanupContextDeadline()
 		<-pgConn.controller
 
@@ -903,14 +896,11 @@ func (pgConn *PgConn) CopyFrom(ctx context.Context, r io.Reader, sql string) (Co
 			buf = buf[0 : n+5]
 			pgio.SetInt32(buf[sp:], int32(n+4))
 
-			err = pgConn.writeAll(buf)
+			_, err = pgConn.conn.Write(buf)
 			if err != nil {
+				pgConn.hardClose()
 				cleanupContextDeadline()
-				if err, ok := err.(net.Error); ok && err.Timeout() {
-					go pgConn.recoverFromTimeoutDuringCopyFrom()
-				} else {
-					<-pgConn.controller
-				}
+				<-pgConn.controller
 
 				return "", preferContextOverNetTimeoutError(ctx, err)
 			}
@@ -1386,8 +1376,9 @@ func (pgConn *PgConn) ExecBatch(ctx context.Context, batch *Batch) *MultiResultR
 	multiResult.cleanupContextDeadline = contextDoneToConnDeadline(ctx, pgConn.conn)
 
 	batch.buf = (&pgproto3.Sync{}).Encode(batch.buf)
-	err := pgConn.writeAll(batch.buf)
+	_, err := pgConn.conn.Write(batch.buf)
 	if err != nil {
+		pgConn.hardClose()
 		multiResult.cleanupContextDeadline()
 		multiResult.closed = true
 		multiResult.err = preferContextOverNetTimeoutError(ctx, err)
diff --git a/pgconn/pgconn_test.go b/pgconn/pgconn_test.go
index 7fb01e2c..dbf9b840 100644
--- a/pgconn/pgconn_test.go
+++ b/pgconn/pgconn_test.go
@@ -863,7 +863,7 @@ func TestConnCopyFromCanceled(t *testing.T) {
 	assert.Equal(t, int64(0), ct.RowsAffected())
 	require.Equal(t, context.DeadlineExceeded, err)
 
-	ensureConnValid(t, pgConn)
+	assert.False(t, pgConn.IsAlive())
 }
 
 func TestConnCopyFromGzipReader(t *testing.T) {