Limit max send message size to 8192 bytes (#132)

.github/workflows/ci.yaml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        go-version: ['1.16', '1.15', '1.14', '1.13']
+        go-version: ['1.17', '1.16', '1.15', '1.14', '1.13']
 
     steps:
       - name: Check out repository

README.md

@@ -8,7 +8,7 @@ vertica-sql-go is a native Go adapter for the Vertica (http://www.vertica.com) d
 
 Please check out [release notes](https://github.com/vertica/vertica-sql-go/releases) to learn about the latest improvements.
 
-vertica-sql-go has been tested with Vertica 11.0.1 and Go 1.13/1.14/1.15/1.16.
+vertica-sql-go has been tested with Vertica 11.0.1 and Go 1.13/1.14/1.15/1.16/1.17.
 
 ## Installation
 

connection.go

@@ -355,9 +355,16 @@ func (v *connection) sendMessageTo(msg msgs.FrontEndMsg, conn net.Conn) error {
 
 		_, result = conn.Write(sizeBytes)
 
-		if result == nil {
-			if len(msgBytes) > 0 {
-				_, result = conn.Write(msgBytes)
+		if result == nil && len(msgBytes) > 0 {
+			size := 8192 // Max msg size, consistent with how the server works
+			pos := 0
+			var sent int
+			for pos < len(msgBytes) {
+				sent, result = conn.Write(msgBytes[pos:min(pos+size, len(msgBytes))])
+				if result != nil {
+					break
+				}
+				pos += sent
 			}
 		}
 	}
@@ -371,6 +378,13 @@ func (v *connection) sendMessageTo(msg msgs.FrontEndMsg, conn net.Conn) error {
 	return result
 }
 
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
 func (v *connection) handshake() error {
 
 	if v.connURL.User == nil {