Added more tests for new UPDATE ... ORDER BY ... LIMIT optimization

heap/_check.c

@@ -167,7 +167,7 @@ static int check_one_rb_key(HP_INFO *info, uint keynr, ulong records,
   ulong found= 0;
   byte *key, *recpos;
   uint key_length;
-  uint not_used;
+  uint not_used[2];
   
   if ((key= tree_search_edge(&keydef->rb_tree, info->parents,
 			     &info->last_pos, offsetof(TREE_ELEMENT, left))))
@@ -177,7 +177,7 @@ static int check_one_rb_key(HP_INFO *info, uint keynr, ulong records,
       memcpy(&recpos, key + (*keydef->get_key_length)(keydef,key), sizeof(byte*));
       key_length= hp_rb_make_key(keydef, info->recbuf, recpos, 0);
       if (ha_key_cmp(keydef->seg, (uchar*) info->recbuf, (uchar*) key,
-		     key_length, SEARCH_FIND | SEARCH_SAME, &not_used))
+		     key_length, SEARCH_FIND | SEARCH_SAME, not_used))
       {
 	error= 1;
 	DBUG_PRINT("error",("Record in wrong link:  key: %d  Record: %lx\n", 

heap/hp_create.c

@@ -170,9 +170,9 @@ int heap_create(const char *name, uint keys, HP_KEYDEF *keydef,
 
 static int keys_compare(heap_rb_param *param, uchar *key1, uchar *key2)
 {
-  uint not_used;
+  uint not_used[2];
   return ha_key_cmp(param->keyseg, key1, key2, param->key_length, 
-		    param->search_flag, &not_used);
+		    param->search_flag, not_used);
 }
 
 static void init_block(HP_BLOCK *block, uint reclength, ulong min_records,

include/my_base.h

@@ -319,8 +319,6 @@ enum ha_base_keytype {
 #define SEARCH_NULL_ARE_EQUAL 32768	/* NULL in keys are equal */
 #define SEARCH_NULL_ARE_NOT_EQUAL 65536	/* NULL in keys are not equal */
 
-#define SEARCH_RETURN_B_POS (65536*2)   /* see ha_key_cmp for description */
-
 	/* bits in opt_flag */
 #define QUICK_USED	1
 #define READ_CACHE_USED	2

myisam/mi_check.c

@@ -619,6 +619,7 @@ int mi_collect_stats_nonulls_next(HA_KEYSEG *keyseg, ulonglong *notnull,
 {
   uint diffs[2];
   uint first_null_seg, kp;
+  HA_KEYSEG *seg;
 
   /* 
      Find the first keypart where values are different or either of them is
@@ -629,9 +630,8 @@ int mi_collect_stats_nonulls_next(HA_KEYSEG *keyseg, ulonglong *notnull,
                       value in prev_key.
   */
   ha_key_cmp(keyseg, prev_key, last_key, USE_WHOLE_KEY, 
-             SEARCH_FIND | SEARCH_NULL_ARE_NOT_EQUAL | SEARCH_RETURN_B_POS,
-             diffs);
-  HA_KEYSEG *seg= keyseg + diffs[0] - 1;
+             SEARCH_FIND | SEARCH_NULL_ARE_NOT_EQUAL, diffs);
+  seg= keyseg + diffs[0] - 1;
 
   /* Find first NULL in last_key */
   first_null_seg= ha_find_null(seg, last_key + diffs[1]) - keyseg;
@@ -658,7 +658,7 @@ static int chk_index(MI_CHECK *param, MI_INFO *info, MI_KEYDEF *keyinfo,
   uchar key[MI_MAX_POSSIBLE_KEY_BUFF],*temp_buff,*keypos,*old_keypos,*endpos;
   my_off_t next_page,record;
   char llbuff[22];
-  uint diff_pos;
+  uint diff_pos[2];
   DBUG_ENTER("chk_index");
   DBUG_DUMP("buff",(byte*) buff,mi_getint(buff));
 
@@ -716,7 +716,7 @@ static int chk_index(MI_CHECK *param, MI_INFO *info, MI_KEYDEF *keyinfo,
     }
     if ((*keys)++ &&
 	(flag=ha_key_cmp(keyinfo->seg,info->lastkey,key,key_length,
-			 comp_flag, &diff_pos)) >=0)
+			 comp_flag, diff_pos)) >=0)
     {
       DBUG_DUMP("old",(byte*) info->lastkey, info->lastkey_length);
       DBUG_DUMP("new",(byte*) key, key_length);
@@ -735,14 +735,14 @@ static int chk_index(MI_CHECK *param, MI_INFO *info, MI_KEYDEF *keyinfo,
         if (param->stats_method == MI_STATS_METHOD_NULLS_NOT_EQUAL)
           ha_key_cmp(keyinfo->seg,info->lastkey,key,USE_WHOLE_KEY,
                      SEARCH_FIND | SEARCH_NULL_ARE_NOT_EQUAL,
-                     &diff_pos);
+                     diff_pos);
         else if (param->stats_method == MI_STATS_METHOD_IGNORE_NULLS)
         {
-          diff_pos= mi_collect_stats_nonulls_next(keyinfo->seg, 
+          diff_pos[0]= mi_collect_stats_nonulls_next(keyinfo->seg, 
                                                   param->notnull_count,
                                                   info->lastkey, key);
         }
-	param->unique_count[diff_pos-1]++;
+	param->unique_count[diff_pos[0]-1]++;
       }
       else
       {  
@@ -3340,15 +3340,15 @@ int sort_write_record(MI_SORT_PARAM *sort_param)
 static int sort_key_cmp(MI_SORT_PARAM *sort_param, const void *a,
 			const void *b)
 {
-  uint not_used;
+  uint not_used[2];
   return (ha_key_cmp(sort_param->seg, *((uchar**) a), *((uchar**) b),
-		     USE_WHOLE_KEY, SEARCH_SAME,&not_used));
+		     USE_WHOLE_KEY, SEARCH_SAME, not_used));
 } /* sort_key_cmp */
 
 
 static int sort_key_write(MI_SORT_PARAM *sort_param, const void *a)
 {
-  uint diff_pos;
+  uint diff_pos[2];
   char llbuff[22],llbuff2[22];
   SORT_INFO *sort_info=sort_param->sort_info;
   MI_CHECK *param= sort_info->param;
@@ -3358,19 +3358,19 @@ static int sort_key_write(MI_SORT_PARAM *sort_param, const void *a)
   {
     cmp=ha_key_cmp(sort_param->seg,sort_info->key_block->lastkey,
 		   (uchar*) a, USE_WHOLE_KEY,SEARCH_FIND | SEARCH_UPDATE,
-		   &diff_pos);
+		   diff_pos);
     if (param->stats_method == MI_STATS_METHOD_NULLS_NOT_EQUAL)
       ha_key_cmp(sort_param->seg,sort_info->key_block->lastkey,
                  (uchar*) a, USE_WHOLE_KEY, 
-                 SEARCH_FIND | SEARCH_NULL_ARE_NOT_EQUAL, &diff_pos);
+                 SEARCH_FIND | SEARCH_NULL_ARE_NOT_EQUAL, diff_pos);
     else if (param->stats_method == MI_STATS_METHOD_IGNORE_NULLS)
     {
-      diff_pos= mi_collect_stats_nonulls_next(sort_param->seg,
+      diff_pos[0]= mi_collect_stats_nonulls_next(sort_param->seg,
                                                  sort_param->notnull,
                                                  sort_info->key_block->lastkey,
                                                  (uchar*)a);
     }
-    sort_param->unique[diff_pos-1]++;
+    sort_param->unique[diff_pos[0]-1]++;
   }
   else
   {

myisam/mi_rnext_same.c

@@ -28,7 +28,7 @@
 int mi_rnext_same(MI_INFO *info, byte *buf)
 {
   int error;
-  uint inx,not_used;
+  uint inx,not_used[2];
   MI_KEYDEF *keyinfo;
   DBUG_ENTER("mi_rnext_same");
 
@@ -69,7 +69,7 @@ int mi_rnext_same(MI_INFO *info, byte *buf)
 			       info->s->state.key_root[inx])))
           break;
         if (ha_key_cmp(keyinfo->seg, info->lastkey, info->lastkey2,
-                       info->last_rkey_length, SEARCH_FIND, &not_used))
+                       info->last_rkey_length, SEARCH_FIND, not_used))
         {
           error=1;
           my_errno=HA_ERR_END_OF_FILE;

myisam/mi_search.c

@@ -128,13 +128,13 @@ int _mi_search(register MI_INFO *info, register MI_KEYDEF *keyinfo,
 
   if ((nextflag & (SEARCH_SMALLER | SEARCH_LAST)) && flag != 0)
   {
-    uint not_used;
+    uint not_used[2];
     if (_mi_get_prev_key(info,keyinfo, buff, info->lastkey, keypos,
                          &info->lastkey_length))
       goto err;
     if (!(nextflag & SEARCH_SMALLER) &&
         ha_key_cmp(keyinfo->seg, info->lastkey, key, key_len, SEARCH_FIND,
-                    &not_used))
+                   not_used))
     {
       my_errno=HA_ERR_KEY_NOT_FOUND;                    /* Didn't find key */
       goto err;
@@ -178,7 +178,7 @@ int _mi_bin_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
 {
   reg4 int start,mid,end,save_end;
   int flag;
-  uint totlength,nod_flag,not_used;
+  uint totlength,nod_flag,not_used[2];
   DBUG_ENTER("_mi_bin_search");
 
   LINT_INIT(flag);
@@ -192,7 +192,7 @@ int _mi_bin_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
   {
     mid= (start+end)/2;
     if ((flag=ha_key_cmp(keyinfo->seg,page+(uint) mid*totlength,key,key_len,
-                          comp_flag,&not_used))
+                         comp_flag, not_used))
         >= 0)
       end=mid;
     else
@@ -200,7 +200,7 @@ int _mi_bin_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
   }
   if (mid != start)
     flag=ha_key_cmp(keyinfo->seg,page+(uint) start*totlength,key,key_len,
-                     comp_flag,&not_used);
+                     comp_flag, not_used);
   if (flag < 0)
     start++;                    /* point at next, bigger key */
   *ret_pos=page+(uint) start*totlength;
@@ -241,7 +241,7 @@ int _mi_seq_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
                    uchar *buff, my_bool *last_key)
 {
   int flag;
-  uint nod_flag,length,not_used;
+  uint nod_flag,length,not_used[2];
   uchar t_buff[MI_MAX_KEY_BUFF],*end;
   DBUG_ENTER("_mi_seq_search");
 
@@ -262,7 +262,7 @@ int _mi_seq_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
       DBUG_RETURN(MI_FOUND_WRONG_KEY);
     }
     if ((flag=ha_key_cmp(keyinfo->seg,t_buff,key,key_len,comp_flag,
-                          &not_used)) >= 0)
+                         not_used)) >= 0)
       break;
 #ifdef EXTRA_DEBUG
     DBUG_PRINT("loop",("page: %lx  key: '%s'  flag: %d", (long) page, t_buff,
@@ -503,9 +503,9 @@ int _mi_prefix_search(MI_INFO *info, register MI_KEYDEF *keyinfo, uchar *page,
       cmp_rest:
 	  if (key_len_left>0)
 	  {
-	    uint not_used;
+	    uint not_used[2];
 	    if ((flag = ha_key_cmp(keyinfo->seg+1,vseg,
-				   k,key_len_left,nextflag,&not_used)) >= 0)
+				   k, key_len_left, nextflag, not_used)) >= 0)
 	      break;
 	  }
 	  else

myisam/mi_write.c

@@ -885,10 +885,10 @@ int _mi_ck_write_tree(register MI_INFO *info, uint keynr, uchar *key,
 
 static int keys_compare(bulk_insert_param *param, uchar *key1, uchar *key2)
 {
-  uint not_used;
+  uint not_used[2];
   return ha_key_cmp(param->info->s->keyinfo[param->keynr].seg,
                     key1, key2, USE_WHOLE_KEY, SEARCH_SAME,
-		     &not_used);
+                    not_used);
 }
 
 

myisammrg/myrg_queue.c

@@ -20,9 +20,9 @@ static int queue_key_cmp(void *keyseg, byte *a, byte *b)
 {
   MI_INFO *aa=((MYRG_TABLE *)a)->table;
   MI_INFO *bb=((MYRG_TABLE *)b)->table;
-  uint not_used;
+  uint not_used[2];
   int ret= ha_key_cmp((HA_KEYSEG *)keyseg, aa->lastkey, bb->lastkey,
-		       USE_WHOLE_KEY, SEARCH_FIND, &not_used);
+		       USE_WHOLE_KEY, SEARCH_FIND, not_used);
   return ret < 0 ? -1 : ret > 0 ? 1 : 0;
 } /* queue_key_cmp */
 

mysql-test/r/update.result

@@ -263,8 +263,8 @@ test
 delete from t1 where count(*)=1;
 ERROR HY000: Invalid use of group function
 drop table t1;
-create table t1 ( a int, index (a) );
-insert into t1 values (0),(0),(0),(0),(0),(0),(0),(0);
+create table t1 ( a int, b int default 0, index (a) );
+insert into t1 (a) values (0),(0),(0),(0),(0),(0),(0),(0);
 flush status;
 select a from t1 order by a limit 1;
 a
@@ -278,15 +278,16 @@ Handler_read_prev	0
 Handler_read_rnd	0
 Handler_read_rnd_next	0
 flush status;
-update t1 set a=unix_timestamp() order by a limit 1;
+update t1 set a=9999 order by a limit 1;
+update t1 set b=9999 order by a limit 1;
 show status like 'handler_read%';
 Variable_name	Value
 Handler_read_first	1
 Handler_read_key	0
 Handler_read_next	0
 Handler_read_prev	0
-Handler_read_rnd	1
-Handler_read_rnd_next	0
+Handler_read_rnd	2
+Handler_read_rnd_next	9
 flush status;
 delete from t1 order by a limit 1;
 show status like 'handler_read%';
@@ -318,7 +319,21 @@ Handler_read_next	0
 Handler_read_prev	0
 Handler_read_rnd	1
 Handler_read_rnd_next	9
-select count(*) from t1;
-count(*)
-5
+select * from t1;
+a	b
+0	0
+0	0
+0	0
+0	0
+0	0
+update t1 set a=a+10,b=1 order by a limit 3;
+update t1 set a=a+11,b=2 order by a limit 3;
+update t1 set a=a+12,b=3 order by a limit 3;
+select * from t1 order by a;
+a	b
+11	2
+21	2
+22	3
+22	3
+23	3
 drop table t1;

mysql-test/t/update.test

@@ -228,15 +228,16 @@ delete from t1 where count(*)=1;
 drop table t1;
 
 # BUG#12915: Optimize "DELETE|UPDATE ... ORDER BY ... LIMIT n" to use an index
-create table t1 ( a int, index (a) );
-insert into t1 values (0),(0),(0),(0),(0),(0),(0),(0);
+create table t1 ( a int, b int default 0, index (a) );
+insert into t1 (a) values (0),(0),(0),(0),(0),(0),(0),(0);
 
 flush status;
 select a from t1 order by a limit 1;
 show status like 'handler_read%';
 
 flush status;
-update t1 set a=unix_timestamp() order by a limit 1;
+update t1 set a=9999 order by a limit 1;
+update t1 set b=9999 order by a limit 1;
 show status like 'handler_read%';
 
 flush status;
@@ -253,7 +254,11 @@ flush status;
 delete from t1 order by a limit 1;
 show status like 'handler_read%';
 
-select count(*) from t1;
+select * from t1;
+update t1 set a=a+10,b=1 order by a limit 3;
+update t1 set a=a+11,b=2 order by a limit 3;
+update t1 set a=a+12,b=3 order by a limit 3;
+select * from t1 order by a;
 
 drop table t1;
 # End of 4.1 tests

mysys/my_handler.c

@@ -86,12 +86,6 @@ static int compare_bin(uchar *a, uint a_length, uchar *b, uint b_length,
 		position and this should also be compared
     diff_pos    OUT Number of first keypart where values differ, counting 
                 from one.
-  
-  DESCRIPTION
-    If SEARCH_RETURN_B_POS flag is set, diff_pos must point to array of 2
-    values, first value has the meaning as described in parameter
-    description above, the second value is:
-
     diff_pos[1] OUT  (b + diff_pos[1]) points to first value in tuple b
                       that is different from corresponding value in tuple a.
   
@@ -137,8 +131,6 @@ int ha_key_cmp(register HA_KEYSEG *keyseg, register uchar *a,
     uchar *end;
     uint piks=! (keyseg->flag & HA_NO_SORT);
     (*diff_pos)++;
-
-    if (nextflag & SEARCH_RETURN_B_POS)
     diff_pos[1]= (uint)(b - orig_b);
 
     /* Handle NULL part */

sql/records.cc

@@ -28,11 +28,10 @@ static int rr_from_pointers(READ_RECORD *info);
 static int rr_from_cache(READ_RECORD *info);
 static int init_rr_cache(READ_RECORD *info);
 static int rr_cmp(uchar *a,uchar *b);
-
+static int rr_index_first(READ_RECORD *info);
 static int rr_index(READ_RECORD *info);
 
 
-
 /*
   Initialize READ_RECORD structure to perform full index scan
 
@@ -58,26 +57,19 @@ void init_read_record_idx(READ_RECORD *info, THD *thd, TABLE *table,
                           bool print_error, uint idx)
 {
   bzero((char*) info,sizeof(*info));
-  info->thd=thd;
-  info->table=table;
+  info->table= table;
   info->file=  table->file;
-  info->forms= &info->table;		/* Only one table */
-    
   info->record= table->record[0];
-  info->ref_length= table->file->ref_length;
+  info->print_error= print_error;
 
-  info->select=NULL;
-  info->print_error=print_error;
-  info->ignore_not_found_rows= 0;
   table->status=0;			/* And it's always found */
-
   if (!table->file->inited)
   {
     table->file->ha_index_init(idx);
     table->file->extra(HA_EXTRA_RETRIEVE_PRIMARY_KEY);
   }
-  info->read_record= rr_index;
-  info->first= TRUE;
+  /* read_record will be changed to rr_index in rr_index_first */
+  info->read_record= rr_index_first;
 }
 
 
@@ -204,6 +196,21 @@ void end_read_record(READ_RECORD *info)
   }
 }
 
+static int rr_handle_error(READ_RECORD *info, int error)
+{
+  if (error == HA_ERR_END_OF_FILE)
+    error= -1;
+  else
+  {
+    if (info->print_error)
+      info->table->file->print_error(error, MYF(0));
+    if (error < 0)                            // Fix negative BDB errno
+      error= 1;
+  }
+  return error;
+}
+
+
 	/* Read a record from head-database */
 
 static int rr_quick(READ_RECORD *info)
@@ -218,15 +225,7 @@ static int rr_quick(READ_RECORD *info)
     }
     if (tmp != HA_ERR_RECORD_DELETED)
     {
-      if (tmp == HA_ERR_END_OF_FILE)
-        tmp= -1;
-      else
-      {
-        if (info->print_error)
-          info->file->print_error(tmp,MYF(0));
-        if (tmp < 0)				// Fix negative BDB errno
-          tmp=1;
-      }
+      tmp= rr_handle_error(info, tmp);
       break;
     }
   }
@@ -235,7 +234,31 @@ static int rr_quick(READ_RECORD *info)
 
 
 /*
-  A READ_RECORD::read_record implementation that reads index sequentially
+  Reads first row in an index scan
+
+  SYNOPSIS
+    rr_index_first()
+    info  	Scan info
+  
+  RETURN
+    0   Ok
+    -1  End of records 
+    1   Error   
+*/
+
+
+static int rr_index_first(READ_RECORD *info)
+{
+  int tmp= info->file->index_first(info->record);
+  info->read_record= rr_index;
+  if (tmp)
+    tmp= rr_handle_error(info, tmp);
+  return tmp;
+}
+
+
+/*
+  Reads index sequentially after first row
 
   SYNOPSIS
     rr_index()
@@ -251,43 +274,16 @@ static int rr_quick(READ_RECORD *info)
     1   Error   
 */
 
+
 static int rr_index(READ_RECORD *info)
 {
-  int tmp;
-  while (1)
-  {
-    if (info->first)
-    {
-      info->first= FALSE;
-      tmp= info->file->index_first(info->record);
-    }
-    else
-      tmp= info->file->index_next(info->record);
-    
-    if (!tmp)
-      break;
-    if (info->thd->killed)
-    {
-      my_error(ER_SERVER_SHUTDOWN,MYF(0));
-      return 1;
-    }
-    if (tmp != HA_ERR_RECORD_DELETED)
-    {
-      if (tmp == HA_ERR_END_OF_FILE)
-        tmp= -1;
-      else
-      {
-        if (info->print_error)
-          info->table->file->print_error(tmp,MYF(0));
-        if (tmp < 0)                            // Fix negative BDB errno
-          tmp=1;
-      }
-      break;
-    }
-  }
+  int tmp= info->file->index_next(info->record);
+  if (tmp)
+    tmp= rr_handle_error(info, tmp);
   return tmp;
 }
 
+
 static int rr_sequential(READ_RECORD *info)
 {
   int tmp;
@@ -298,17 +294,13 @@ static int rr_sequential(READ_RECORD *info)
       my_error(ER_SERVER_SHUTDOWN,MYF(0));
       return 1;
     }
+    /*
+      rnd_next can return RECORD_DELETED for MyISAM when one thread is
+      reading and another deleting without locks.
+    */
     if (tmp != HA_ERR_RECORD_DELETED)
     {
-      if (tmp == HA_ERR_END_OF_FILE)
-	tmp= -1;
-      else
-      {
-	if (info->print_error)
-	  info->table->file->print_error(tmp,MYF(0));
-	if (tmp < 0)				// Fix negative BDB errno
-	  tmp=1;
-      }
+      tmp= rr_handle_error(info, tmp);
       break;
     }
   }
@@ -319,23 +311,18 @@ static int rr_sequential(READ_RECORD *info)
 static int rr_from_tempfile(READ_RECORD *info)
 {
   int tmp;
-tryNext:
+  for (;;)
+  {
     if (my_b_read(info->io_cache,info->ref_pos,info->ref_length))
       return -1;					/* End of file */
-  if ((tmp=info->file->rnd_pos(info->record,info->ref_pos)))
-  {
-    if (tmp == HA_ERR_END_OF_FILE)
-      tmp= -1;
-    else if (tmp == HA_ERR_RECORD_DELETED ||
+    if (!(tmp=info->file->rnd_pos(info->record,info->ref_pos)))
+      break;
+    /* The following is extremely unlikely to happen */
+    if (tmp == HA_ERR_RECORD_DELETED ||
         (tmp == HA_ERR_KEY_NOT_FOUND && info->ignore_not_found_rows))
-      goto tryNext;
-    else
-    {
-      if (info->print_error)
-	info->file->print_error(tmp,MYF(0));
-      if (tmp < 0)				// Fix negative BDB errno
-	tmp=1;
-    }
+      continue;
+    tmp= rr_handle_error(info, tmp);
+    break;
   }
   return tmp;
 } /* rr_from_tempfile */
@@ -373,26 +360,23 @@ static int rr_from_pointers(READ_RECORD *info)
 {
   int tmp;
   byte *cache_pos;
-tryNext:
+
+  for (;;)
+  {
     if (info->cache_pos == info->cache_end)
       return -1;					/* End of file */
-  cache_pos=info->cache_pos;
-  info->cache_pos+=info->ref_length;
+    cache_pos= info->cache_pos;
+    info->cache_pos+= info->ref_length;
 
-  if ((tmp=info->file->rnd_pos(info->record,cache_pos)))
-  {
-    if (tmp == HA_ERR_END_OF_FILE)
-      tmp= -1;
-    else if (tmp == HA_ERR_RECORD_DELETED ||
+    if (!(tmp=info->file->rnd_pos(info->record,cache_pos)))
+      break;
+
+    /* The following is extremely unlikely to happen */
+    if (tmp == HA_ERR_RECORD_DELETED ||
         (tmp == HA_ERR_KEY_NOT_FOUND && info->ignore_not_found_rows))
-      goto tryNext;
-    else
-    {
-      if (info->print_error)
-	info->file->print_error(tmp,MYF(0));
-      if (tmp < 0)				// Fix negative BDB errno
-	tmp=1;
-    }
+      continue;
+    tmp= rr_handle_error(info, tmp);
+    break;
   }
   return tmp;
 }

sql/sql_load.cc

@@ -818,12 +818,9 @@ int READ_INFO::read_field()
           *to++ = (byte) unescape((char) chr);
           continue;
         }
-        else
-        {
         PUSH(chr);
         chr= escape_char;
       }
-      }
 #ifdef ALLOW_LINESEPARATOR_IN_STRINGS
       if (chr == line_term_char)
 #else

sql/sql_update.cc

@@ -148,7 +148,7 @@ int mysql_update(THD *thd,
   }
   if (!select && limit != HA_POS_ERROR)
   {
-    if (MAX_KEY != (used_index= get_index_for_order(table, order, limit)))
+    if ((used_index= get_index_for_order(table, order, limit)) != MAX_KEY)
       need_sort= FALSE;
   }
   /* If running in safe sql mode, don't allow updates without keys */
@@ -171,14 +171,14 @@ int mysql_update(THD *thd,
     used_key_is_modified= (!select->quick->unique_key_range() &&
 			   check_if_key_used(table, used_index, fields));
   }
-  else if (used_index != MAX_KEY)
+  else
   {
+    used_key_is_modified= 0;
+    if (used_index == MAX_KEY)                  // no index for sort order
+      used_index= table->file->key_used_on_scan;
+    if (used_index != MAX_KEY)
       used_key_is_modified= check_if_key_used(table, used_index, fields);
   }
-  else if ((used_index=table->file->key_used_on_scan) < MAX_KEY)
-    used_key_is_modified=check_if_key_used(table, used_index, fields);
-  else
-    used_key_is_modified=0;
 
   if (used_key_is_modified || order)
   {
@@ -190,11 +190,11 @@ int mysql_update(THD *thd,
     if (used_index < MAX_KEY && old_used_keys.is_set(used_index))
     {
       table->key_read=1;
-      table->file->extra(HA_EXTRA_KEYREAD); //todo: psergey: check
+      table->file->extra(HA_EXTRA_KEYREAD);
     }
 
     /* note: can actually avoid sorting below.. */
-    if (order && need_sort)
+    if (order && (need_sort || used_key_is_modified))
     {
       /*
 	Doing an ORDER BY;  Let filesort find and sort the rows we are going
@@ -204,6 +204,7 @@ int mysql_update(THD *thd,
       SORT_FIELD  *sortorder;
       ha_rows examined_rows;
 
+      used_index= MAX_KEY;                   // For call to init_read_record()
       table->sort.io_cache = (IO_CACHE *) my_malloc(sizeof(IO_CACHE),
 						    MYF(MY_FAE | MY_ZEROFILL));
       if (!(sortorder=make_unireg_sortorder(order, &length)) ||
@@ -266,9 +267,6 @@ int mysql_update(THD *thd,
       limit= tmp_limit;
       end_read_record(&info);
      
-      /* if we got here we must not use index in the main update loop below */
-      used_index= MAX_KEY;
-      
       /* Change select to use tempfile */
       if (select)
       {

sql/structs.h

@@ -132,7 +132,6 @@ typedef struct st_read_record {			/* Parameter to read_record */
   byte	*cache,*cache_pos,*cache_end,*read_positions;
   IO_CACHE *io_cache;
   bool print_error, ignore_not_found_rows;
-  bool first; /* used only with rr_index_read */
 } READ_RECORD;