server: add comment for #7252 (#7549)

pingcap · Aug 30, 2018 · f915575 · f915575
1 parent 528d959
commit f915575
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/server/driver_tidb.go b/server/driver_tidb.go
@@ -403,6 +403,8 @@ func convertColumnInfo(fld *ast.ResultField) (ci *ColumnInfo) {
 		// * Utf-8, the multiple is 3
 		// * utf8mb4, the multiple is 4
 		// So the large enough multiple is 4 in here.
+		// We used to check non-string types to avoid the truncation problem in some MySQL
+		// client such as Navicat. Now we only allow string type enter this branch.
 		ci.ColumnLength = ci.ColumnLength * mysql.MaxBytesOfCharacter
 	}