fix_max_connections to resize alarm_queue (Bug #1435)

include/queues.h

@@ -49,6 +49,7 @@ int init_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
 int reinit_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
                  pbool max_at_top, queue_compare compare,
                  void *first_cmp_arg);
+int resize_queue(QUEUE *queue, uint max_elements);
 void delete_queue(QUEUE *queue);
 void queue_insert(QUEUE *queue,byte *element);
 byte *queue_remove(QUEUE *queue,uint idx);

include/thr_alarm.h

@@ -100,6 +100,7 @@ typedef struct st_alarm {
 #define thr_alarm_init(A) (*(A))=0
 #define thr_alarm_in_use(A) (*(A)!= 0)
 void init_thr_alarm(uint max_alarm);
+void resize_thr_alarm(uint max_alarms);
 my_bool thr_alarm(thr_alarm_t *alarmed, uint sec, ALARM *buff);
 void thr_alarm_kill(pthread_t thread_id);
 void thr_end_alarm(thr_alarm_t *alarmed);

mysys/queues.c

@@ -44,25 +44,35 @@ int init_queue(QUEUE *queue, uint max_elements, uint offset_to_key,
 }
 
 /*
-  Reinitialize queue for new usage;  Note that you can't currently resize
-  the number of elements!  If you need this, fix it :)
+  Reinitialize queue for new usage;
 */
 
-
 int reinit_queue(QUEUE *queue, uint max_elements, uint offset_to_key,
                pbool max_at_top, int (*compare) (void *, byte *, byte *),
                void *first_cmp_arg)
 {
   DBUG_ENTER("reinit_queue");
-  if (queue->max_elements < max_elements)
-    /* It's real easy to do realloc here, just don't want to bother */
-    DBUG_RETURN(my_errno=EE_OUTOFMEMORY);
-
   queue->elements=0;
   queue->compare=compare;
   queue->first_cmp_arg=first_cmp_arg;
   queue->offset_to_key=offset_to_key;
   queue->max_at_top= max_at_top ? (-1 ^ 1) : 0;
+  resize_queue(queue, max_elements);
+  DBUG_RETURN(0);
+}
+
+int resize_queue(QUEUE *queue, uint max_elements)
+{
+  byte **new_root;
+  DBUG_ENTER("resize_queue");
+  if (queue->max_elements == max_elements)
+    DBUG_RETURN(0);
+  if ((new_root= (byte **) my_realloc((void *)queue->root,
+          (max_elements+1)*sizeof(void*), MYF(MY_WME))) == 0)
+    DBUG_RETURN(1);
+  set_if_smaller(queue->elements, max_elements);
+  queue->max_elements=max_elements;
+  queue->root=new_root;
   DBUG_RETURN(0);
 }
 

mysys/thr_alarm.c

@@ -120,6 +120,16 @@ void init_thr_alarm(uint max_alarms)
   DBUG_VOID_RETURN;
 }
 
+void resize_thr_alarm(uint max_alarms)
+{
+  pthread_mutex_lock(&LOCK_alarm);
+  /* it's ok not to shrink the queue sometimes */
+  if (alarm_queue.elements < max_alarms)
+    resize_queue(&alarm_queue,max_alarms+1);
+  pthread_mutex_unlock(&LOCK_alarm);
+  return;
+}
+
 /*
   Request alarm after sec seconds.
 

sql/set_var.cc

@@ -86,6 +86,7 @@ static void fix_myisam_max_extra_sort_file_size(THD *thd, enum_var_type type);
 static void fix_myisam_max_sort_file_size(THD *thd, enum_var_type type);
 static void fix_max_binlog_size(THD *thd, enum_var_type type);
 static void fix_max_relay_log_size(THD *thd, enum_var_type type);
+static void fix_max_connections(THD *thd, enum_var_type type);
 
 /*
   Variable definition list
@@ -147,7 +148,8 @@ sys_var_long_ptr	sys_max_binlog_size("max_binlog_size",
 					    &max_binlog_size,
                                             fix_max_binlog_size);
 sys_var_long_ptr	sys_max_connections("max_connections",
-					    &max_connections);
+					    &max_connections,
+                                            fix_max_connections);
 sys_var_long_ptr	sys_max_connect_errors("max_connect_errors",
 					       &max_connect_errors);
 sys_var_long_ptr	sys_max_delayed_threads("max_delayed_threads",
@@ -689,7 +691,7 @@ static void fix_key_buffer_size(THD *thd, enum_var_type type)
 }
 
 
-void fix_delay_key_write(THD *thd, enum_var_type type)
+extern void fix_delay_key_write(THD *thd, enum_var_type type)
 {
   switch ((enum_delay_key_write) delay_key_write_options) {
   case DELAY_KEY_WRITE_NONE:
@@ -705,7 +707,7 @@ void fix_delay_key_write(THD *thd, enum_var_type type)
   }
 }
 
-void fix_max_binlog_size(THD *thd, enum_var_type type)
+static void fix_max_binlog_size(THD *thd, enum_var_type type)
 {
   DBUG_ENTER("fix_max_binlog_size");
   DBUG_PRINT("info",("max_binlog_size=%lu max_relay_log_size=%lu",
@@ -716,7 +718,7 @@ void fix_max_binlog_size(THD *thd, enum_var_type type)
   DBUG_VOID_RETURN;
 }
 
-void fix_max_relay_log_size(THD *thd, enum_var_type type)
+static void fix_max_relay_log_size(THD *thd, enum_var_type type)
 {
   DBUG_ENTER("fix_max_relay_log_size");
   DBUG_PRINT("info",("max_binlog_size=%lu max_relay_log_size=%lu",
@@ -726,6 +728,13 @@ void fix_max_relay_log_size(THD *thd, enum_var_type type)
   DBUG_VOID_RETURN;
 }
 
+#include <thr_alarm.h>
+static void
+fix_max_connections(THD *thd, enum_var_type type)
+{
+  resize_thr_alarm(max_connections);
+}
+
 bool sys_var_long_ptr::update(THD *thd, set_var *var)
 {
   ulonglong tmp= var->value->val_int();