From 25eb21e556c442fe806c846b3936e6e7fa46f4ef Mon Sep 17 00:00:00 2001
From: Danny Hermes <dhermes@blend.com>
Date: Thu, 19 Nov 2020 12:38:16 -0600
Subject: [PATCH] Mark `net.Conn` failed writes as recoverable when 0 bytes
 were written.

---
 conn.go  | 13 ++++++++++++-
 error.go |  3 +++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/conn.go b/conn.go
index f313c149..0d96600e 100644
--- a/conn.go
+++ b/conn.go
@@ -891,9 +891,20 @@ func (cn *conn) Exec(query string, args []driver.Value) (res driver.Result, err
 	return r, err
 }
 
+type safeRetryError struct {
+	Err error
+}
+
+func (se *safeRetryError) Error() string {
+	return se.Err.Error()
+}
+
 func (cn *conn) send(m *writeBuf) {
-	_, err := cn.c.Write(m.wrap())
+	n, err := cn.c.Write(m.wrap())
 	if err != nil {
+		if n == 0 {
+			err = &safeRetryError{Err: err}
+		}
 		panic(err)
 	}
 }
diff --git a/error.go b/error.go
index 3d66ba7c..a227e083 100644
--- a/error.go
+++ b/error.go
@@ -495,6 +495,9 @@ func (cn *conn) errRecover(err *error) {
 	case *net.OpError:
 		cn.bad = true
 		*err = v
+	case *safeRetryError:
+		cn.bad = true
+		*err = driver.ErrBadConn
 	case error:
 		if v == io.EOF || v.(error).Error() == "remote error: handshake failure" {
 			*err = driver.ErrBadConn