comments

sql/handler.h

@@ -129,7 +129,7 @@ enum enum_alter_inplace_result {
 */ 
 #define HA_PRIMARY_KEY_REQUIRED_FOR_POSITION (1ULL << 16) 
 #define HA_CAN_RTREEKEYS       (1ULL << 17)
-#define HA_NOT_DELETE_WITH_CACHE (1ULL << 18)
+#define HA_NOT_DELETE_WITH_CACHE (1ULL << 18) /* unused */
 /*
   The following is we need to a primary key to delete (and update) a row.
   If there is no primary key, all columns needs to be read on update and delete
@@ -143,7 +143,7 @@ enum enum_alter_inplace_result {
 #define HA_HAS_OLD_CHECKSUM    (1ULL << 24)
 /* Table data are stored in separate files (for lower_case_table_names) */
 #define HA_FILE_BASED	       (1ULL << 26)
-#define HA_NO_VARCHAR	       (1ULL << 27)
+#define HA_NO_VARCHAR	       (1ULL << 27) /* unused */
 #define HA_CAN_BIT_FIELD       (1ULL << 28) /* supports bit fields */
 #define HA_NEED_READ_RANGE_BUFFER (1ULL << 29) /* for read_multi_range */
 #define HA_ANY_INDEX_MAY_BE_UNIQUE (1ULL << 30)

sql/sql_admin.cc

@@ -622,16 +622,14 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
 
     /*
       Close all instances of the table to allow MyISAM "repair"
-      to rename files.
+      (which is internally also used from "optimize") to rename files.
       @todo: This code does not close all instances of the table.
       It only closes instances in other connections, but if this
       connection has LOCK TABLE t1 a READ, t1 b WRITE,
       both t1 instances will be kept open.
       There is no need to execute this branch for InnoDB, which does
-      repair by recreate. There is no need to do it for OPTIMIZE,
-      which doesn't move files around.
-      Hence, this code should be moved to prepare_for_repair(),
-      and executed only for MyISAM engine.
+      repair by recreate.
+      Hence, this code should be executed only for MyISAM engine.
     */
     if (lock_type == TL_WRITE && !table->table->s->tmp_table)
     {