1 files changed, 54 insertions, 33 deletions

diff --git a/sql/handler.cc b/sql/handler.cc
index 28f399818c4..56db355f45e 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -1105,76 +1105,97 @@ int ha_create_table(const char *name, HA_CREATE_INFO *create_info,
   DBUG_RETURN(error != 0);
 }
 
-	/* Use key cacheing on all databases */
+static int NEAR_F delete_file(const char *name,const char *ext,int extflag)
+{
+  char buff[FN_REFLEN];
+  VOID(fn_format(buff,name,"",ext,extflag | 4));
+  return(my_delete_with_symlink(buff,MYF(MY_WME)));
+}
+
+void st_ha_check_opt::init()
+{
+  flags= sql_flags= 0;
+  sort_buffer_size = current_thd->variables.myisam_sort_buff_size;
+}
+
+
+/*****************************************************************************
+  Key cache handling.
+
+  This code is only relevant for ISAM/MyISAM tables
+
+  key_cache->cache may be 0 only in the case where a key cache is not
+  initialized or when we where not able to init the key cache in a previous
+  call to ha_init_key_cache() (probably out of memory)
+*****************************************************************************/
+
+/* Init a key cache if it has not been initied before */
 
-int ha_key_cache(KEY_CACHE_VAR *key_cache)
+
+int ha_init_key_cache(const char *name, KEY_CACHE_VAR *key_cache)
 {
+  DBUG_ENTER("ha_init_key_cache");
+
   if (!key_cache->cache)
   {
-    /*
-      The following mutex is not really needed as long as keybuff_size is
-      treated as a long value, but we use the mutex here to guard for future
-      changes.
-    */
     pthread_mutex_lock(&LOCK_global_system_variables);
-    if (!key_cache->block_size)
-      key_cache->block_size= dflt_key_cache_block_size;
-    if (!key_cache->buff_size)
-      key_cache->buff_size= dflt_key_buff_size;
     long tmp_buff_size= (long) key_cache->buff_size;
     long tmp_block_size= (long) key_cache->block_size;
     pthread_mutex_unlock(&LOCK_global_system_variables);
-    return !init_key_cache(&key_cache->cache,
-			   tmp_block_size,
-			   tmp_buff_size,
-                           key_cache);
+    DBUG_RETURN(!init_key_cache(&key_cache->cache,
+				tmp_block_size,
+				tmp_buff_size,
+				key_cache));
   }
-  return 0;
+  DBUG_RETURN(0);
 }
 
+
+/* Resize key cache */
+
 int ha_resize_key_cache(KEY_CACHE_VAR *key_cache)
 {
+  DBUG_ENTER("ha_resize_key_cache");
+
   if (key_cache->cache)
   {
     pthread_mutex_lock(&LOCK_global_system_variables);
     long tmp_buff_size= (long) key_cache->buff_size;
     long tmp_block_size= (long) key_cache->block_size;
     pthread_mutex_unlock(&LOCK_global_system_variables);
-    return !resize_key_cache(&key_cache->cache, tmp_block_size,
-                             tmp_buff_size);
+    DBUG_RETURN(!resize_key_cache(&key_cache->cache, tmp_block_size,
+				  tmp_buff_size));
   }
-  return 0;
+  DBUG_RETURN(0);
 }
 
+
+/* Change parameters for key cache (like size) */
+
 int ha_change_key_cache_param(KEY_CACHE_VAR *key_cache)
 {
   if (key_cache->cache)
-  {
     change_key_cache_param(key_cache->cache);
-  }
   return 0;
 }
 
+/* Free memory allocated by a key cache */
+
 int ha_end_key_cache(KEY_CACHE_VAR *key_cache)
 {
   if (key_cache->cache)
   {
-    end_key_cache(&key_cache->cache, 1);
-    return key_cache->cache ? 1 : 0;
+    end_key_cache(key_cache->cache, 1);		// Can never fail
+    key_cache->cache= 0;
   }
   return 0;
 }
 
+/* Move all tables from one key cache to another one */
 
-static int NEAR_F delete_file(const char *name,const char *ext,int extflag)
+int ha_change_key_cache(KEY_CACHE_VAR *old_key_cache,
+			KEY_CACHE_VAR *new_key_cache)
 {
-  char buff[FN_REFLEN];
-  VOID(fn_format(buff,name,"",ext,extflag | 4));
-  return(my_delete_with_symlink(buff,MYF(MY_WME)));
-}
-
-void st_ha_check_opt::init()
-{
-  flags= sql_flags= 0;
-  sort_buffer_size = current_thd->variables.myisam_sort_buff_size;
+  mi_change_key_cache(old_key_cache, new_key_cache);
+  return 0;
 }