fix todo

Author: methane

connection.go

@@ -37,6 +37,7 @@ type mysqlConn struct {
 	sequence            uint8
 	compressionSequence uint8
 	parseTime           bool
+	compress            bool
 
 	// for context support (Go 1.8+)
 	watching bool
@@ -64,7 +65,7 @@ func (mc *mysqlConn) syncSeqNo() {
 	// This is done in `net_flush()` in MySQL and MariaDB.
 	// https://github.com/mariadb-corporation/mariadb-connector-c/blob/8228164f850b12353da24df1b93a1e53cc5e85e9/libmariadb/ma_net.c#L170-L171
 	// https://github.com/mysql/mysql-server/blob/824e2b4064053f7daf17d7f3f84b7a3ed92e5fb4/sql-common/net_serv.cc#L293
-	if mc.cfg.compress {
+	if mc.compress {
 		mc.sequence = mc.compressionSequence
 	}
 }

connector.go

@@ -168,7 +168,7 @@ func (c *connector) Connect(ctx context.Context) (driver.Conn, error) {
 		return nil, err
 	}
 
-	if mc.cfg.compress {
+	if mc.compress {
 		mc.packetReader = newCompressedReader(&mc.buf, mc)
 		mc.packetWriter = newCompressedWriter(mc.packetWriter, mc)
 	}

packets.go

@@ -215,9 +215,6 @@ func (mc *mysqlConn) readHandshakePacket() (data []byte, plugin string, err erro
 			return nil, "", ErrNoTLS
 		}
 	}
-	if mc.flags&clientCompress == 0 {
-		mc.cfg.compress = false
-	}
 
 	pos += 2
 
@@ -281,8 +278,9 @@ func (mc *mysqlConn) writeHandshakeResponsePacket(authResp []byte, plugin string
 	if mc.cfg.ClientFoundRows {
 		clientFlags |= clientFoundRows
 	}
-	if mc.cfg.compress {
+	if mc.cfg.compress && mc.flags&clientCompress == clientCompress {
 		clientFlags |= clientCompress
+		mc.compress = true
 	}
 	// To enable TLS / SSL
 	if mc.cfg.TLS != nil {