Merge of fix for BUG#4258 from 4.1.

Needs additional manual merge.

include/keycache.h

@@ -88,12 +88,13 @@ typedef struct st_key_cache
   ulong param_division_limit;   /* min. percentage of warm blocks           */
   ulong param_age_threshold;    /* determines when hot block is downgraded  */
 
-  /* Statistics variables */
+  /* Statistics variables. These are reset in reset_key_cache_counters(). */
   ulong global_blocks_changed;	/* number of currently dirty blocks         */
   ulong global_cache_w_requests;/* number of write requests (write hits)    */
   ulong global_cache_write;     /* number of writes from the cache to files */
   ulong global_cache_r_requests;/* number of read requests (read hits)      */
   ulong global_cache_read;      /* number of reads from files to the cache  */
+
   int blocks;                   /* max number of blocks in the cache        */
   my_bool in_init;		/* Set to 1 in MySQL during init/resize     */
 } KEY_CACHE;
@@ -132,5 +133,7 @@ extern my_bool multi_key_cache_set(const byte *key, uint length,
 				   KEY_CACHE *key_cache);
 extern void multi_key_cache_change(KEY_CACHE *old_data,
 				   KEY_CACHE *new_data);
+extern int reset_key_cache_counters(const char *name,
+                                    KEY_CACHE *key_cache);
 C_MODE_END
 #endif /* _keycache_h */

mysys/mf_keycache.c

@@ -2444,6 +2444,41 @@ static int flush_all_key_blocks(KEY_CACHE *keycache)
 }
 
 
+/*
+  Reset the counters of a key cache.
+
+  SYNOPSIS
+    reset_key_cache_counters()
+    name       the name of a key cache
+    key_cache  pointer to the key kache to be reset
+
+  DESCRIPTION
+   This procedure is used by process_key_caches() to reset the counters of all
+   currently used key caches, both the default one and the named ones.
+
+  RETURN
+    0 on success (always because it can't fail)
+*/
+
+int reset_key_cache_counters(const char *name, KEY_CACHE *key_cache)
+{
+  DBUG_ENTER("reset_key_cache_counters");
+  if (!key_cache->key_cache_inited)
+  {
+    DBUG_PRINT("info", ("Key cache %s not initialized.", name));
+    DBUG_RETURN(0);
+  }
+  DBUG_PRINT("info", ("Resetting counters for key cache %s.", name));
+
+  key_cache->global_blocks_changed= 0;   /* Key_blocks_not_flushed */
+  key_cache->global_cache_r_requests= 0; /* Key_read_requests */
+  key_cache->global_cache_read= 0;       /* Key_reads */
+  key_cache->global_cache_w_requests= 0; /* Key_write_requests */
+  key_cache->global_cache_write= 0;      /* Key_writes */
+  DBUG_RETURN(0);
+}
+
+
 #ifndef DBUG_OFF
 /*
   Test if disk-cache is ok

sql/mysql_priv.h

@@ -1064,7 +1064,6 @@ extern struct system_variables global_system_variables;
 extern struct system_variables max_system_variables;
 extern struct system_status_var global_status_var;
 extern struct rand_struct sql_rand;
-extern KEY_CACHE *sql_key_cache;
 
 extern const char *opt_date_time_formats[];
 extern KNOWN_DATE_TIME_FORMAT known_date_time_formats[];

sql/mysqld.cc

@@ -395,7 +395,6 @@ struct system_status_var global_status_var;
 
 MY_TMPDIR mysql_tmpdir_list;
 MY_BITMAP temp_pool;
-KEY_CACHE *sql_key_cache;
 
 CHARSET_INFO *system_charset_info, *files_charset_info ;
 CHARSET_INFO *national_charset_info, *table_alias_charset;
@@ -1867,14 +1866,14 @@ We will try our best to scrape up some info that will hopefully help diagnose\n\
 the problem, but since we have already crashed, something is definitely wrong\n\
 and this may fail.\n\n");
   fprintf(stderr, "key_buffer_size=%lu\n", 
-          (ulong) sql_key_cache->key_cache_mem_size);
+          (ulong) dflt_key_cache->key_cache_mem_size);
   fprintf(stderr, "read_buffer_size=%ld\n", global_system_variables.read_buff_size);
   fprintf(stderr, "max_used_connections=%ld\n", max_used_connections);
   fprintf(stderr, "max_connections=%ld\n", max_connections);
   fprintf(stderr, "threads_connected=%d\n", thread_count);
   fprintf(stderr, "It is possible that mysqld could use up to \n\
 key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections = %ld K\n\
-bytes of memory\n", ((ulong) sql_key_cache->key_cache_mem_size +
+bytes of memory\n", ((ulong) dflt_key_cache->key_cache_mem_size +
 		     (global_system_variables.read_buff_size +
 		      global_system_variables.sortbuff_size) *
 		     max_connections)/ 1024);
@@ -2141,12 +2140,12 @@ extern "C" void *signal_hand(void *arg __attribute__((unused)))
     case SIGHUP:
       if (!abort_loop)
       {
+	mysql_print_status((THD*) 0);		// Print some debug info
 	reload_acl_and_cache((THD*) 0,
 			     (REFRESH_LOG | REFRESH_TABLES | REFRESH_FAST |
 			      REFRESH_GRANT |
 			      REFRESH_THREADS | REFRESH_HOSTS),
 			     (TABLE_LIST*) 0, NULL); // Flush logs
-	mysql_print_status((THD*) 0);		// Send debug some info
       }
       break;
 #ifdef USE_ONE_SIGNAL_HAND
@@ -2820,8 +2819,6 @@ server.");
 
   /* call ha_init_key_cache() on all key caches to init them */
   process_key_caches(&ha_init_key_cache);
-  /* We must set dflt_key_cache in case we are using ISAM tables */
-  dflt_key_cache= sql_key_cache;
 
 #if defined(HAVE_MLOCKALL) && defined(MCL_CURRENT) && !defined(EMBEDDED_LIBRARY)
   if (locked_in_memory && !getuid())
@@ -5875,10 +5872,10 @@ static void mysql_init_variables(void)
   threads.empty();
   thread_cache.empty();
   key_caches.empty();
-  multi_keycache_init();
-  if (!(sql_key_cache= get_or_create_key_cache(default_key_cache_base.str,
+  if (!(dflt_key_cache= get_or_create_key_cache(default_key_cache_base.str,
 					       default_key_cache_base.length)))
     exit(1);
+  multi_keycache_init(); /* set key_cache_hash.default_value = dflt_key_cache */
 
   /* Initialize structures that is used when processing options */
   replicate_rewrite_db.empty();

sql/set_var.cc

@@ -2232,7 +2232,7 @@ bool sys_var_key_buffer_size::update(THD *thd, set_var *var)
 
   if (!tmp)					// Zero size means delete
   {
-    if (key_cache == sql_key_cache)
+    if (key_cache == dflt_key_cache)
       goto end;					// Ignore default key cache
 
     if (key_cache->key_cache_inited)		// If initied
@@ -2246,7 +2246,7 @@ bool sys_var_key_buffer_size::update(THD *thd, set_var *var)
 					      base_name->length, &list);
       key_cache->in_init= 1;
       pthread_mutex_unlock(&LOCK_global_system_variables);
-      error= reassign_keycache_tables(thd, key_cache, sql_key_cache);
+      error= reassign_keycache_tables(thd, key_cache, dflt_key_cache);
       pthread_mutex_lock(&LOCK_global_system_variables);
       key_cache->in_init= 0;
     }

sql/sql_parse.cc

@@ -5867,6 +5867,7 @@ void kill_one_thread(THD *thd, ulong id, bool only_kill_query)
     my_error(error, MYF(0), id);
 }
 
+
 /* Clear most status variables */
 
 static void refresh_status(void)
@@ -5876,17 +5877,6 @@ static void refresh_status(void)
   {
     if (ptr->type == SHOW_LONG)
       *(ulong*) ptr->value= 0;
-    else if (ptr->type == SHOW_KEY_CACHE_LONG)
-    {
-      /*
-	Reset value in 'default' key cache.
-	This needs to be recoded when we have thread specific key values
-      */
-      char *value= (((char*) sql_key_cache) +
-		    (uint) ((char*) (ptr->value) -
-			    (char*) &dflt_key_cache_var));
-      *(ulong*) value= 0;
-    }
     else if (ptr->type == SHOW_LONG_STATUS)
     {
       THD *thd= current_thd;
@@ -5895,6 +5885,8 @@ static void refresh_status(void)
       bzero((char*) &thd->status_var, sizeof(thd->status_var));
     }
   }
+  /* Reset the counters of all key caches (default and named). */
+  process_key_caches(reset_key_cache_counters);
   pthread_mutex_unlock(&LOCK_status);
 }