Merge pull request #27 from RiveryIO/fix/eitam/MySQLCharsetNull

MySQL Charset NULL Error

Author: eitamring

canal/canal.go

@@ -438,11 +438,14 @@ func (c *Canal) GenerateCharsetQuery() (string, error) {
 query := `
  SELECT 
  c.ORDINAL_POSITION,
- CASE 
- WHEN c.CHARACTER_SET_NAME IS NOT NULL THEN c.CHARACTER_SET_NAME
- WHEN c.DATA_TYPE IN ('binary','varbinary','tinyblob','blob','mediumblob','longblob') THEN col.CHARACTER_SET_NAME
- ELSE col.CHARACTER_SET_NAME
- END AS CHARACTER_SET_NAME,
+ COALESCE(
+ CASE 
+ WHEN c.CHARACTER_SET_NAME IS NOT NULL THEN c.CHARACTER_SET_NAME
+ WHEN c.DATA_TYPE IN ('binary','varbinary','tinyblob','blob','mediumblob','longblob') THEN col.CHARACTER_SET_NAME
+ ELSE col.CHARACTER_SET_NAME
+ END,
+ 'utf8mb4'
+ ) AS CHARACTER_SET_NAME,
  c.COLUMN_NAME
  FROM 
  information_schema.COLUMNS c
@@ -465,12 +468,19 @@ func (c *Canal) setColumnsCharsetFromRows(tableRegex string, rows *sql.Rows) err
 c.cfg.ColumnCharset[tableRegex] = make(map[int]string)
 for rows.Next() {
 var ordinal int
-var charset, columnName string
+var charset, columnName sql.NullString
 if err := rows.Scan(&ordinal, &charset, &columnName); err != nil {
 return errors.Annotate(err, "failed to scan charset row")
 }
-c.cfg.ColumnCharset[tableRegex][ordinal] = charset
-log.Infof("Column Name: %s, Ordinal: %d, Charset: %s", columnName, ordinal, charset)
+
+// Handle NULL charset values properly
+charsetValue := "utf8mb4" // default charset
+if charset.Valid && charset.String != "" {
+charsetValue = charset.String
+}
+
+c.cfg.ColumnCharset[tableRegex][ordinal] = charsetValue
+log.Infof("Column Name: %s, Ordinal: %d, Charset: %s", columnName.String, ordinal, charsetValue)
 }
 
 return rows.Err()
@@ -514,13 +524,12 @@ func (c *Canal) GetColumnsCharsets() error {
 return fmt.Errorf("error occurred while executing query: %s on db: %s on table: %s. error: %v",
 query, dbName, tableName, errors.Trace(err))
 }
-// Ensure rows are closed after processing
-func() {
-defer rows.Close()
-if err := c.setColumnsCharsetFromRows(tableRegex, rows); err != nil {
-panic(fmt.Errorf("failed to set charset from rows: %w", err))
-}
-}()
+
+// Process rows with proper error handling
+defer rows.Close()
+if err := c.setColumnsCharsetFromRows(tableRegex, rows); err != nil {
+return fmt.Errorf("failed to set charset from rows for table %s: %w", tableRegex, err)
+}
 
 }