MariaDB Metadata skipping and DEPRECATE_EOF

benchmark_test.go

@@ -129,7 +129,7 @@ func BenchmarkExec(b *testing.B) {
 	b.ReportAllocs()
 	b.ResetTimer()
 
-	for i := 0; i <  concurrencyLevel; i++ {
+	for i := 0; i < concurrencyLevel; i++ {
 		go func() {
 			for {
 				if atomic.AddInt64(&remain, -1) < 0 {
@@ -400,7 +400,7 @@ func benchmark10kRows(b *testing.B, compress bool) {
 	}
 
 	args := make([]any, 200)
-	for i := 1; i < 200; i+=2 {
+	for i := 1; i < 200; i += 2 {
 		args[i] = sval
 	}
 	for i := 0; i < 10000; i += 100 {
@@ -455,3 +455,58 @@ func BenchmarkReceive10kRows(b *testing.B) {
 func BenchmarkReceive10kRowsCompressed(b *testing.B) {
 	benchmark10kRows(b, true)
 }
+
+// BenchmarkReceiveMetadata measures performance of receiving lots of metadata compare to data in rows
+func BenchmarkReceiveMetadata(b *testing.B) {
+	tb := (*TB)(b)
+
+	// Create a table with 1000 integer fields
+	createTableQuery := "CREATE TABLE large_integer_table ("
+	for i := 0; i < 1000; i++ {
+		createTableQuery += fmt.Sprintf("col_%d INT", i)
+		if i < 999 {
+			createTableQuery += ", "
+		}
+	}
+	createTableQuery += ")"
+
+	// Initialize database
+	db := initDB(b, false,
+		"DROP TABLE IF EXISTS large_integer_table",
+		createTableQuery,
+		"INSERT INTO large_integer_table VALUES ("+
+			strings.Repeat("0,", 999)+"0)", // Insert a row of zeros
+	)
+	defer db.Close()
+
+	b.Run("query", func(b *testing.B) {
+		db.SetMaxIdleConns(0)
+		db.SetMaxIdleConns(1)
+
+		// Create a slice to scan all columns
+		values := make([]any, 1000)
+		valuePtrs := make([]any, 1000)
+		for j := range values {
+			valuePtrs[j] = &values[j]
+		}
+
+		b.ReportAllocs()
+		b.ResetTimer()
+
+		// Prepare a SELECT query to retrieve metadata
+		stmt := tb.checkStmt(db.Prepare("SELECT * FROM large_integer_table LIMIT 1"))
+		defer stmt.Close()
+
+		// Benchmark metadata retrieval
+		for range b.N {
+			rows := tb.checkRows(stmt.Query())
+
+			rows.Next()
+			// Scan the row
+			err := rows.Scan(valuePtrs...)
+			tb.check(err)
+
+			rows.Close()
+		}
+	})
+}

connection.go

@@ -33,7 +33,8 @@ type mysqlConn struct {
 	connector        *connector
 	maxAllowedPacket int
 	maxWriteSize     int
-	flags            clientFlag
+	capabilities     capabilityFlag
+	extCapabilities  extendedCapabilityFlag
 	status           statusFlag
 	sequence         uint8
 	compressSequence uint8
@@ -223,13 +224,21 @@ func (mc *mysqlConn) Prepare(query string) (driver.Stmt, error) {
 	columnCount, err := stmt.readPrepareResultPacket()
 	if err == nil {
 		if stmt.paramCount > 0 {
-			if err = mc.readUntilEOF(); err != nil {
+			if err = mc.skipColumns(stmt.paramCount); err != nil {
 				return nil, err
 			}
 		}
 
 		if columnCount > 0 {
-			err = mc.readUntilEOF()
+			if mc.extCapabilities&clientCacheMetadata != 0 {
+				if stmt.columns, err = mc.readColumns(int(columnCount)); err != nil {
+					return nil, err
+				}
+			} else {
+				if err = mc.skipColumns(int(columnCount)); err != nil {
+					return nil, err
+				}
+			}
 		}
 	}
 
@@ -370,19 +379,19 @@ func (mc *mysqlConn) exec(query string) error {
 	}
 
 	// Read Result
-	resLen, err := handleOk.readResultSetHeaderPacket()
+	resLen, _, err := handleOk.readResultSetHeaderPacket()
 	if err != nil {
 		return err
 	}
 
 	if resLen > 0 {
 		// columns
-		if err := mc.readUntilEOF(); err != nil {
+		if err := mc.skipColumns(resLen); err != nil {
 			return err
 		}
 
 		// rows
-		if err := mc.readUntilEOF(); err != nil {
+		if err := mc.skipRows(); err != nil {
 			return err
 		}
 	}
@@ -419,7 +428,7 @@ func (mc *mysqlConn) query(query string, args []driver.Value) (*textRows, error)
 
 	// Read Result
 	var resLen int
-	resLen, err = handleOk.readResultSetHeaderPacket()
+	resLen, _, err = handleOk.readResultSetHeaderPacket()
 	if err != nil {
 		return nil, err
 	}
@@ -453,22 +462,22 @@ func (mc *mysqlConn) getSystemVar(name string) ([]byte, error) {
 	}
 
 	// Read Result
-	resLen, err := handleOk.readResultSetHeaderPacket()
+	resLen, _, err := handleOk.readResultSetHeaderPacket()
 	if err == nil {
 		rows := new(textRows)
 		rows.mc = mc
 		rows.rs.columns = []mysqlField{{fieldType: fieldTypeVarChar}}
 
 		if resLen > 0 {
 			// Columns
-			if err := mc.readUntilEOF(); err != nil {
+			if err := mc.skipColumns(resLen); err != nil {
 				return nil, err
 			}
 		}
 
 		dest := make([]driver.Value, resLen)
 		if err = rows.readRow(dest); err == nil {
-			return dest[0].([]byte), mc.readUntilEOF()
+			return dest[0].([]byte), mc.skipRows()
 		}
 	}
 	return nil, err

connector.go

@@ -131,12 +131,16 @@ func (c *connector) Connect(ctx context.Context) (driver.Conn, error) {
 	mc.buf = newBuffer()
 
 	// Reading Handshake Initialization Packet
-	authData, plugin, err := mc.readHandshakePacket()
+	authData, serverCapabilities, serverExtCapabilities, plugin, err := mc.readHandshakePacket()
 	if err != nil {
 		mc.cleanup()
 		return nil, err
 	}
 
+	if mc.cfg.TLS != nil && serverCapabilities&clientSSL == 0 {
+		return nil, fmt.Errorf("TLS is required, but server doesn't support it")
+	}
+
 	if plugin == "" {
 		plugin = defaultAuthPlugin
 	}
@@ -153,6 +157,7 @@ func (c *connector) Connect(ctx context.Context) (driver.Conn, error) {
 			return nil, err
 		}
 	}
+	mc.initCapabilities(serverCapabilities, serverExtCapabilities, mc.cfg)
 	if err = mc.writeHandshakeResponsePacket(authResp, plugin); err != nil {
 		mc.cleanup()
 		return nil, err
@@ -167,7 +172,8 @@ func (c *connector) Connect(ctx context.Context) (driver.Conn, error) {
 		return nil, err
 	}
 
-	if mc.cfg.compress && mc.flags&clientCompress == clientCompress {
+	// compression is enabled after auth, not right after sending handshake response.
+	if mc.capabilities&clientCompress > 0 {
 		mc.compress = true
 		mc.compIO = newCompIO(mc)
 	}

const.go

@@ -42,11 +42,12 @@ const (
 	iERR          byte = 0xff
 )
 
-// https://dev.mysql.com/doc/internals/en/capability-flags.html#packet-Protocol::CapabilityFlags
-type clientFlag uint32
+// https://dev.mysql.com/doc/dev/mysql-server/latest/group__group__cs__capabilities__flags.html
+// https://mariadb.com/kb/en/connection/#capabilities
+type capabilityFlag uint32
 
 const (
-	clientLongPassword clientFlag = 1 << iota
+	clientMySQL capabilityFlag = 1 << iota
 	clientFoundRows
 	clientLongFlag
 	clientConnectWithDB
@@ -73,6 +74,18 @@ const (
 	clientDeprecateEOF
 )
 
+// https://mariadb.com/kb/en/connection/#capabilities
+type extendedCapabilityFlag uint32
+
+const (
+	progressIndicator extendedCapabilityFlag = 1 << iota
+	clientComMulti
+	clientStmtBulkOperations
+	clientExtendedMetadata
+	clientCacheMetadata
+	clientUnitBulkResult
+)
+
 const (
 	comQuit byte = iota + 1
 	comInitDB