myisammrg::index_next_same

myisammrg/Makefile.am:
  myrg_rnext_same.c added

include/myisammrg.h

@@ -84,6 +84,7 @@ extern int myrg_rfirst(MYRG_INFO *file,byte *buf,int inx);
 extern int myrg_rlast(MYRG_INFO *file,byte *buf,int inx);
 extern int myrg_rnext(MYRG_INFO *file,byte *buf,int inx);
 extern int myrg_rprev(MYRG_INFO *file,byte *buf,int inx);
+extern int myrg_rnext_same(MYRG_INFO *file,byte *buf);
 extern int myrg_rkey(MYRG_INFO *file,byte *buf,int inx,const byte *key,
 		       uint key_len, enum ha_rkey_function search_flag);
 extern int myrg_rrnd(MYRG_INFO *file,byte *buf,ulonglong pos);

myisam/mi_rkey.c

@@ -38,7 +38,15 @@ int mi_rkey(MI_INFO *info, byte *buf, int inx, const byte *key, uint key_len,
   info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
   info->last_key_func=search_flag;
 
-  if (!info->use_packed_key)
+  if (info->once_flags & USE_PACKED_KEYS)
+  {
+    /* key is already packed! */
+    key_buff=info->lastkey+info->s->base.max_key_length;
+    info->last_rkey_length=pack_key_length=key_len;
+    bmove(key_buff,key,key_len);
+    info->once_flags&= ~USE_PACKED_KEYS;
+  }
+  else
   {
     if (key_len == 0)
       key_len=USE_WHOLE_KEY;
@@ -48,13 +56,6 @@ int mi_rkey(MI_INFO *info, byte *buf, int inx, const byte *key, uint key_len,
     DBUG_EXECUTE("key",_mi_print_key(DBUG_FILE,share->keyinfo[inx].seg,
 				     key_buff,pack_key_length););
   }
-  else
-  {
-    /* key is already packed! */
-    key_buff=info->lastkey+info->s->base.max_key_length;
-    info->last_rkey_length=pack_key_length=key_len;
-    bmove(key_buff,key,key_len);
-  }
 
   if (fast_mi_readinfo(info))
     goto err;

myisam/mi_rrnd.c

@@ -46,7 +46,10 @@ int mi_rrnd(MI_INFO *info, byte *buf, register my_off_t filepos)
       filepos= info->nextpos;
   }
 
-  info->lastinx= -1;				/* Can't forward or backward */
+  if (info->once_flags & RRND_PRESERVE_LASTINX)
+    info->once_flags&= ~RRND_PRESERVE_LASTINX;
+  else
+    info->lastinx= -1;                          /* Can't forward or backward */
   /* Init all but update-flag */
   info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
 

myisam/myisamdef.h

@@ -267,7 +267,7 @@ struct st_myisam_info {
   my_bool quick_mode;
   my_bool page_changed;		/* If info->buff can't be used for rnext */
   my_bool buff_used;		/* If info->buff has to be reread for rnext */
-  my_bool use_packed_key;		/* For MYISAMMRG */
+  my_bool once_flags;           /* For MYISAMMRG */
 #ifdef THREAD
   THR_LOCK_DATA lock;
 #endif
@@ -288,6 +288,10 @@ struct st_myisam_info {
 #define WRITEINFO_UPDATE_KEYFILE	1
 #define WRITEINFO_NO_UNLOCK		2
 
+        /* once_flags */
+#define USE_PACKED_KEYS         1
+#define RRND_PRESERVE_LASTINX   2
+
 	/* bits in state.changed */
 
 #define STATE_CHANGED		1

myisammrg/Makefile.am

@@ -21,7 +21,8 @@ libmyisammrg_a_SOURCES = myrg_open.c myrg_extra.c myrg_info.c myrg_locking.c \
 			myrg_rrnd.c myrg_update.c myrg_delete.c myrg_rsame.c \
 			myrg_panic.c myrg_close.c myrg_create.c myrg_static.c \
 			myrg_rkey.c myrg_rfirst.c myrg_rlast.c myrg_rnext.c \
-			myrg_rprev.c myrg_queue.c myrg_write.c myrg_range.c
+			myrg_rprev.c myrg_queue.c myrg_write.c myrg_range.c \
+			myrg_rnext_same.c
 
 # Don't update the files from bitkeeper
 %::SCCS/s.%

myisammrg/myrg_rkey.c

@@ -62,9 +62,8 @@ int myrg_rkey(MYRG_INFO *info,byte *record,int inx, const byte *key,
     }
     else
     {
-      mi->use_packed_key=1;
+      mi->once_flags|= USE_PACKED_KEYS;
       err=mi_rkey(mi,0,inx,key_buff,pack_key_length,search_flag);
-      mi->use_packed_key=0;
     }
     info->last_used_table=table+1;
 
@@ -83,5 +82,6 @@ int myrg_rkey(MYRG_INFO *info,byte *record,int inx, const byte *key,
     return HA_ERR_KEY_NOT_FOUND;
 
   mi=(info->current_table=(MYRG_TABLE *)queue_top(&(info->by_key)))->table;
+  mi->once_flags|= RRND_PRESERVE_LASTINX;
   return mi_rrnd(mi,record,mi->lastpos);
 }

myisammrg/myrg_rnext_same.c

+/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#include "myrg_def.h"
+
+int myrg_rnext_same(MYRG_INFO *info, byte *buf)
+{
+  uint err;
+  MI_INFO *mi;
+
+  if (!info->current_table)
+    return (HA_ERR_KEY_NOT_FOUND);
+
+  err=mi_rnext_same(info->current_table->table,buf);
+  if (err == HA_ERR_END_OF_FILE)
+  {
+    queue_remove(&(info->by_key),0);
+    if (!info->by_key.elements)
+      return HA_ERR_END_OF_FILE;
+
+    mi=(info->current_table=(MYRG_TABLE *)queue_top(&(info->by_key)))->table;
+    mi->once_flags|= RRND_PRESERVE_LASTINX;
+    return mi_rrnd(mi,buf,mi->lastpos);
+  }
+  return err;
+}
+

sql/ha_myisammrg.cc

@@ -160,6 +160,16 @@ int ha_myisammrg::index_last(byte * buf)
   return error;
 }
 
+int ha_myisammrg::index_next_same(byte * buf,
+                                  const byte *key __attribute__((unused)),
+                                  uint length __attribute__((unused)))
+{
+  statistic_increment(ha_read_next_count,&LOCK_status);
+  int error=myrg_rnext_same(file,buf);
+  table->status=error ? STATUS_NOT_FOUND: 0;
+  return error;
+}
+
 int ha_myisammrg::rnd_init(bool scan)
 {
   return myrg_extra(file,HA_EXTRA_RESET,0);

sql/ha_myisammrg.h

@@ -65,15 +65,16 @@ class ha_myisammrg: public handler
   int index_prev(byte * buf);
   int index_first(byte * buf);
   int index_last(byte * buf);
+  int index_next_same(byte *buf, const byte *key, uint keylen);
   int rnd_init(bool scan=1);
   int rnd_next(byte *buf);
   int rnd_pos(byte * buf, byte *pos);
   void position(const byte *record);
-  ha_rows ha_myisammrg::records_in_range(int inx,
-				    const byte *start_key,uint start_key_len,
-				    enum ha_rkey_function start_search_flag,
-				    const byte *end_key,uint end_key_len,
-				    enum ha_rkey_function end_search_flag);
+  ha_rows records_in_range(int inx,
+                           const byte *start_key,uint start_key_len,
+                           enum ha_rkey_function start_search_flag,
+                           const byte *end_key,uint end_key_len,
+                           enum ha_rkey_function end_search_flag);
   my_off_t row_position() { return myrg_position(file); }
   void info(uint);
   int extra(enum ha_extra_function operation);