1 files changed, 128 insertions, 0 deletions
diff --git a/storage/myisam/mi_preload.c b/storage/myisam/mi_preload.c
new file mode 100644
index 00000000..5f9132ab
--- /dev/null
+++ b/storage/myisam/mi_preload.c
@@ -0,0 +1,128 @@
+/* Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
+
+   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; version 2 of the License.
+
+   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
+
+/*
+  Preload indexes into key cache
+*/
+
+#include "myisamdef.h"
+
+
+/*
+  Preload pages of the index file for a table into the key cache
+
+  SYNOPSIS
+    mi_preload()
+      info          open table
+      map           map of indexes to preload into key cache 
+      ignore_leaves only non-leaves pages are to be preloaded
+
+  RETURN VALUE
+    0 if a success. error code - otherwise.
+
+  NOTES.
+    At present pages for all indexes are preloaded.
+    In future only pages for indexes specified in the key_map parameter
+    of the table will be preloaded.
+*/
+
+int mi_preload(MI_INFO *info, ulonglong key_map, my_bool ignore_leaves)
+{
+  uint i;
+  size_t length, block_length= 0;
+  uchar *buff= NULL;
+  MYISAM_SHARE* share= info->s;
+  uint keys= share->state.header.keys;
+  MI_KEYDEF *keyinfo= share->keyinfo;
+  my_off_t key_file_length= share->state.state.key_file_length;
+  my_off_t pos= share->base.keystart;
+  DBUG_ENTER("mi_preload");
+
+  if (!keys || !mi_is_any_key_active(key_map) || key_file_length == pos)
+    DBUG_RETURN(0);
+
+  /* Preload into a non initialized key cache should never happen. */
+  DBUG_ASSERT(share->key_cache->key_cache_inited);
+
+  block_length= keyinfo[0].block_length;
+
+  if (ignore_leaves)
+  {
+    /* Check whether all indexes use the same block size */
+    for (i= 1 ; i < keys ; i++)
+    {
+      if (keyinfo[i].block_length != block_length)
+        DBUG_RETURN(my_errno= HA_ERR_NON_UNIQUE_BLOCK_SIZE);
+    }
+  }
+  else
+    block_length= (size_t)share->key_cache->param_block_size;
+
+  length= info->preload_buff_size/block_length * block_length;
+  set_if_bigger(length, block_length);
+
+  if (!(buff= (uchar *) my_malloc(mi_key_memory_preload_buffer, length,
+                                  MYF(MY_WME))))
+    DBUG_RETURN(my_errno= HA_ERR_OUT_OF_MEM);
+
+  if (flush_key_blocks(share->key_cache, share->kfile, &share->dirty_part_map,
+                       FLUSH_RELEASE))
+    goto err;
+
+  do
+  {
+    /* Read the next block of index file into the preload buffer */
+    if ((my_off_t) length > (key_file_length-pos))
+      length= (size_t) (key_file_length-pos);
+    if (mysql_file_pread(share->kfile, (uchar*) buff, length, pos,
+                         MYF(MY_FAE|MY_FNABP)))
+      goto err;
+
+    if (ignore_leaves)
+    {
+      uchar *end= buff+length;
+      do
+      {
+        if (mi_test_if_nod(buff))
+        {
+          if (key_cache_insert(share->key_cache,
+                               share->kfile, pos, DFLT_INIT_HITS,
+                               buff, (uint)block_length))
+	    goto err;
+	}
+        pos+= block_length;
+      }
+      while ((buff+= block_length) != end);
+      buff= end-length;
+    }
+    else
+    {
+      if (key_cache_insert(share->key_cache,
+                           share->kfile, pos, DFLT_INIT_HITS,
+                           (uchar*) buff, (uint)length))
+	goto err;
+      pos+= length;
+    }
+  }
+  while (pos != key_file_length);
+
+  my_free(buff);
+  DBUG_RETURN(0);
+
+err:
+  my_free(buff);
+  DBUG_RETURN(my_errno= errno);
+}
+