utf8mb4 encoding (#7959)

* use utf8mb4 character set for connections to mysql

* use utf8mb4 character set for tables, shorten varchar fields used in unique indexes

* migration type to update table character set

* update table character sets

* set charset for temp_user.status

* gofmt

pkg/services/sqlstore/migrator/dialect.go

@@ -29,6 +29,7 @@ type Dialect interface {
 
 	TableCheckSql(tableName string) (string, []interface{})
 	RenameTable(oldName string, newName string) string
+	UpdateTableSql(tableName string, columns []*Column) string
 }
 
 func NewDialect(name string) Dialect {
@@ -102,7 +103,7 @@ func (b *BaseDialect) CreateTableSql(table *Table) string {
 
 	sql = sql[:len(sql)-2] + ")"
 	if b.dialect.SupportEngine() {
-		sql += " ENGINE=InnoDB DEFAULT CHARSET UTF8 "
+		sql += " ENGINE=InnoDB DEFAULT CHARSET utf8mb4 COLLATE utf8mb4_unicode_ci"
 	}
 
 	sql += ";"
@@ -160,3 +161,7 @@ func (db *BaseDialect) DropIndexSql(tableName string, index *Index) string {
 	name = index.XName(tableName)
 	return fmt.Sprintf("DROP INDEX %v ON %s", quote(name), quote(tableName))
 }
+
+func (db *BaseDialect) UpdateTableSql(tableName string, columns []*Column) string {
+	return "-- NOT REQUIRED"
+}