Merge mysql.com:/home/ram/work/b31137/b31137.5.0

into  mysql.com:/home/ram/work/b31137/b31137.5.1

include/my_base.h

@@ -244,6 +244,8 @@ enum ha_base_keytype {
                          HA_BINARY_PACK_KEY | HA_FULLTEXT | HA_UNIQUE_CHECK | \
                          HA_SPATIAL | HA_NULL_ARE_EQUAL | HA_GENERATED_KEY)
 
+#define HA_KEY_HAS_PART_KEY_SEG 65536   /* Key contains partial segments */
+
 	/* Automatic bits in key-flag */
 
 #define HA_SPACE_PACK_USED	 4	/* Test for if SPACE_PACK used */

sql/sql_table.cc

@@ -1782,7 +1782,8 @@ bool quick_rm_table(handlerton *base,const char *db,
 /*
   Sort keys in the following order:
   - PRIMARY KEY
-  - UNIQUE keyws where all column are NOT NULL
+  - UNIQUE keys where all column are NOT NULL
+  - UNIQUE keys that don't contain partial segments
   - Other UNIQUE keys
   - Normal keys
   - Fulltext keys
@@ -1793,26 +1794,31 @@ bool quick_rm_table(handlerton *base,const char *db,
 
 static int sort_keys(KEY *a, KEY *b)
 {
-  if (a->flags & HA_NOSAME)
+  ulong a_flags= a->flags, b_flags= b->flags;
+  
+  if (a_flags & HA_NOSAME)
   {
-    if (!(b->flags & HA_NOSAME))
+    if (!(b_flags & HA_NOSAME))
       return -1;
-    if ((a->flags ^ b->flags) & (HA_NULL_PART_KEY | HA_END_SPACE_KEY))
+    if ((a_flags ^ b_flags) & (HA_NULL_PART_KEY | HA_END_SPACE_KEY))
     {
       /* Sort NOT NULL keys before other keys */
-      return (a->flags & (HA_NULL_PART_KEY | HA_END_SPACE_KEY)) ? 1 : -1;
+      return (a_flags & (HA_NULL_PART_KEY | HA_END_SPACE_KEY)) ? 1 : -1;
     }
     if (a->name == primary_key_name)
       return -1;
     if (b->name == primary_key_name)
       return 1;
+    /* Sort keys don't containing partial segments before others */
+    if ((a_flags ^ b_flags) & HA_KEY_HAS_PART_KEY_SEG)
+      return (a_flags & HA_KEY_HAS_PART_KEY_SEG) ? 1 : -1;
   }
-  else if (b->flags & HA_NOSAME)
+  else if (b_flags & HA_NOSAME)
     return 1;					// Prefer b
 
-  if ((a->flags ^ b->flags) & HA_FULLTEXT)
+  if ((a_flags ^ b_flags) & HA_FULLTEXT)
   {
-    return (a->flags & HA_FULLTEXT) ? 1 : -1;
+    return (a_flags & HA_FULLTEXT) ? 1 : -1;
   }
   /*
     Prefer original key order.	usable_key_parts contains here
@@ -2876,6 +2882,10 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
 	else
 	  key_info->flags|= HA_PACK_KEY;
       }
+      /* Check if the key segment is partial, set the key flag accordingly */
+      if (length != sql_field->key_length)
+        key_info->flags|= HA_KEY_HAS_PART_KEY_SEG;
+
       key_length+=length;
       key_part_info++;
 

sql/structs.h

@@ -71,7 +71,7 @@ typedef struct st_key_part_info {	/* Info about a key part */
 
 typedef struct st_key {
   uint	key_length;			/* Tot length of key */
-  uint	flags;				/* dupp key and pack flags */
+  ulong flags;                          /* dupp key and pack flags */
   uint	key_parts;			/* How many key_parts */
   uint  extra_length;
   uint	usable_key_parts;		/* Should normally be = key_parts */