Merge pull request #5 from IBM/interfaceAndMultiQuerySupport

Changes added to support multiquery in simple select

conn.go

@@ -1140,48 +1140,8 @@ func (cn *conn) getFileFromBE(logDir string, filename string, logType int) bool
 	return status
 }
 
-func (cn *conn) simpleQuery(query string) (res *rows, err error) {
-
-	defer cn.errRecover(&err)
+func (cn *conn) connNextResultSet(query string) (res *rows, err error) {
 	var filename readBuf
-
-	if cn.status == CONN_EXECUTING || cn.status == CONN_FETCHING {
-		cn.status = CONN_CONNECTED
-		cn.Sock_clear_socket()
-	} else if cn.status == CONN_CANCELLED {
-		// Control will reach here only when the query was really huge and
-		// even after Cancel request sent, it took too long to cancel and
-		// Conn_clear_sock returned as data was not yet available
-		cn.Sock_clear_socket()
-	}
-	elog.Infoln("Processing query:", query)
-
-	buffer := &writeBuf{
-		buf: []byte{'P', '\xFF', '\xFF', '\xFF', '\xFF'},
-		pos: 1,
-	}
-
-	if cn.commandNumber != -1 {
-		cn.commandNumber++
-		buffer = &writeBuf{
-			buf: []byte{'P', '\x00', '\x00', '\x00', byte(cn.commandNumber)},
-			pos: 1,
-		}
-		if cn.commandNumber > 100000 {
-			cn.commandNumber = 1
-		}
-	}
-
-	buffer.string(query)
-	elog.Debugln(chopPath(funName()), "Buffer sent to nps: ", buffer.buf)
-
-	_, err = cn.c.Write(buffer.buf)
-	if err != nil {
-		panic(err)
-	}
-
-	cn.status = CONN_EXECUTING
-
 	for {
 		response, err := cn.recvSingleByte()
 		if err != nil {
@@ -1192,19 +1152,18 @@ func (cn *conn) simpleQuery(query string) (res *rows, err error) {
 		switch response {
 
 		case 'A': /* Asynchronous Messages are ignored */
+			fallthrough
+		case 0: /* Ignored any null characters */
+			fallthrough
+		case 'L': /* This is receieved from server for batch queries after processing rows */
 			break
 		case 'C': /* portal query command, no tuples returned */
 			length, _ := cn.recv_n_bytes(4)
-			responseBuf, err := cn.recv_n_bytes(int(length.int32()))
-			elog.Debugf(chopPath(funName()), "response received from backend: %s \n", responseBuf.string())
-			return res, err
+			responseBuf, _ := cn.recv_n_bytes(int(length.int32()))
+			resStr := fmt.Sprintf("%s", responseBuf.string())
+			elog.Debugf(chopPath(funName()), "response received from backend: %s \n", resStr)
+			break
 		case 'Z':
-			length, _ := cn.recv_n_bytes(4)
-			responseBuf, err := cn.recv_n_bytes(int(length.int32()))
-			cn.processReadyForQuery(&responseBuf)
-			if res == nil && err == nil {
-				err = errUnexpectedReady
-			}
 			return res, err
 		case 'N':
 			length, _ := cn.recv_n_bytes(4)
@@ -1215,7 +1174,6 @@ func (cn *conn) simpleQuery(query string) (res *rows, err error) {
 			responseBuf, _ := cn.recv_n_bytes(int(length.int32()))
 			elog.Debugf(chopPath(funName()), "response received from backend: %s \n", responseBuf.string())
 			break
-
 		case 'T':
 			length, _ := cn.recv_n_bytes(4)
 			responseBuf, err := cn.recv_n_bytes(int(length.int32()))
@@ -1265,6 +1223,51 @@ func (cn *conn) simpleQuery(query string) (res *rows, err error) {
 	}
 }
 
+func (cn *conn) simpleQuery(query string) (res *rows, err error) {
+
+	defer cn.errRecover(&err)
+
+	if cn.status == CONN_EXECUTING || cn.status == CONN_FETCHING {
+		cn.status = CONN_CONNECTED
+		cn.Sock_clear_socket()
+	} else if cn.status == CONN_CANCELLED {
+		// Control will reach here only when the query was really huge and
+		// even after Cancel request sent, it took too long to cancel and
+		// Conn_clear_sock returned as data was not yet available
+		cn.Sock_clear_socket()
+	}
+	elog.Infoln("Processing query:", query)
+
+	buffer := &writeBuf{
+		buf: []byte{'P', '\xFF', '\xFF', '\xFF', '\xFF'},
+		pos: 1,
+	}
+
+	if cn.commandNumber != -1 {
+		cn.commandNumber++
+		buffer = &writeBuf{
+			buf: []byte{'P', '\x00', '\x00', '\x00', byte(cn.commandNumber)},
+			pos: 1,
+		}
+		if cn.commandNumber > 100000 {
+			cn.commandNumber = 1
+		}
+	}
+
+	buffer.string(query)
+	elog.Debugln(chopPath(funName()), "Buffer sent to nps: ", buffer.buf)
+
+	_, err = cn.c.Write(buffer.buf)
+	if err != nil {
+		panic(err)
+	}
+
+	cn.status = CONN_EXECUTING
+
+	return cn.connNextResultSet(query)
+
+}
+
 type noRows struct{}
 
 var emptyRows noRows
@@ -2015,7 +2018,12 @@ func (res *rows) Next(dest []driver.Value) (err error) {
 
 		case 'C':
 			elog.Debugln(chopPath(funName()), "All Rows fetched")
-			res.done = true
+			re, _ := cn.connNextResultSet("")
+			if re == nil {
+				res.done = true
+			} else {
+				res.next = &re.rowsHeader
+			}
 			return io.EOF
 
 		case 'D':
@@ -2026,6 +2034,7 @@ func (res *rows) Next(dest []driver.Value) (err error) {
 			cn.saveMessage(response, &responseBuf)
 			res.readTuples(dest)
 			return
+
 		case 'X': //	get dbos tuple descriptor
 			cn.recv_n_bytes(4)
 			length, _ := cn.recv_n_bytes(4)
@@ -2039,6 +2048,9 @@ func (res *rows) Next(dest []driver.Value) (err error) {
 			res.status = PGRES_TUPLES_OK
 			res.Res_read_dbos_tuple(dest)
 			return /* continue reading */
+		case 0:
+			res.done = true
+			return io.EOF
 		default:
 			elog.Fatalf(chopPath(funName()), "Unknown response: %d", response)
 		}