fixed bug in parallel repair

include/my_sys.h

@@ -324,7 +324,7 @@ typedef struct st_io_cache_share
   /* to sync on reads into buffer */
   pthread_mutex_t mutex;
   pthread_cond_t  cond;
-  int             count;
+  int             count, total;
   /* actual IO_CACHE that filled the buffer */
   struct st_io_cache *active;
 #ifdef NOT_YET_IMPLEMENTED

myisam/mi_check.c

@@ -2129,7 +2129,7 @@ int mi_repair_parallel(MI_CHECK *param, register MI_INFO *info,
 			const char * name, int rep_quick)
 {
   int got_error;
-  uint i,key, total_key_length;
+  uint i,key, total_key_length, istep;
   ulong rec_length;
   ha_rows start_records;
   my_off_t new_header_length,del;
@@ -2264,8 +2264,8 @@ int mi_repair_parallel(MI_CHECK *param, register MI_INFO *info,
   info->state->records=info->state->del=share->state.split=0;
   info->state->empty=0;
 
-  for (i=key=0 ; key < share->base.keys ;
+  for (i=key=0, istep=1 ; key < share->base.keys ;
-       rec_per_key_part+=sort_param[i].keyinfo->keysegs, i++, key++)
+       rec_per_key_part+=sort_param[i].keyinfo->keysegs, i+=istep, key++)
   {
     sort_param[i].key=key;
     sort_param[i].keyinfo=share->keyinfo+key;
@@ -2276,9 +2276,10 @@ int mi_repair_parallel(MI_CHECK *param, register MI_INFO *info,
 	     (char*) (share->state.rec_per_key_part+
 		      (uint) (rec_per_key_part - param->rec_per_key_part)),
 	     sort_param[i].keyinfo->keysegs*sizeof(*rec_per_key_part));
-      i--;
+      istep=0;
       continue;
     }
+    istep=1;
     if ((!(param->testflag & T_SILENT)))
       printf ("- Fixing index %d\n",key+1);
     sort_param[i].key_read= ((sort_param[i].keyinfo->flag & HA_FULLTEXT) ?

mysys/mf_iocache.c

@@ -441,7 +441,7 @@ void init_io_cache_share(IO_CACHE *info, IO_CACHE_SHARE *s, uint num_threads)
   DBUG_ASSERT(info->type == READ_CACHE);
   pthread_mutex_init(&s->mutex, MY_MUTEX_INIT_FAST);
   pthread_cond_init (&s->cond, 0);
-  s->count=num_threads-1;
+  s->total=s->count=num_threads-1;
   s->active=0; /* to catch errors */
   info->share=s;
   info->read_function=_my_b_read_r;
@@ -456,32 +456,36 @@ void init_io_cache_share(IO_CACHE *info, IO_CACHE_SHARE *s, uint num_threads)
 */
 void remove_io_thread(IO_CACHE *info)
 {
-  pthread_mutex_lock(&info->share->mutex);
+  IO_CACHE_SHARE *s=info->share;
-  if (! info->share->count--)
+
-    pthread_cond_signal(&info->share->cond);
+  pthread_mutex_lock(&s->mutex);
-  pthread_mutex_unlock(&info->share->mutex);
+  s->total--;
+  if (! s->count--)
+    pthread_cond_signal(&s->cond);
+  pthread_mutex_unlock(&s->mutex);
 }
 
 static int lock_io_cache(IO_CACHE *info)
 {
-  pthread_mutex_lock(&info->share->mutex);
+  int total;
-  if (!info->share->count)
+  IO_CACHE_SHARE *s=info->share;
+
+  pthread_mutex_lock(&s->mutex);
+  if (!s->count)
+  {
+    s->count=s->total;
+    return 1;
+  }
+
+  total=s->total;
+  s->count--;
+  pthread_cond_wait(&s->cond, &s->mutex);
+
+  if (s->total < total)
     return 1;
 
-  --(info->share->count);
+  pthread_mutex_unlock(&s->mutex);
-  pthread_cond_wait(&info->share->cond, &info->share->mutex);
-  /*
-    count can be -1 here, if one thread was removed (remove_io_thread)
-    while all others were locked (lock_io_cache).
-    If this is the case, this thread behaves as if count was 0 from the
-    very beginning, that is returns 1 and does not unlock the mutex.
-  */
-  if (++(info->share->count))
-  {
-    pthread_mutex_unlock(&info->share->mutex);
   return 0;
-  }
-  return 1;
 }
 
 static void unlock_io_cache(IO_CACHE *info)
@@ -1132,19 +1136,15 @@ int end_io_cache(IO_CACHE *info)
   DBUG_ENTER("end_io_cache");
 
 #ifdef THREAD
+  /*
+    if IO_CACHE is shared between several threads, only one
+    thread needs to call end_io_cache() - just as init_io_cache()
+    should be called only once and then memcopy'ed
+  */
   if (info->share)
   {
-#ifdef SAFE_MUTEX
-  /* simple protection against multi-close: destroying share first */
-    if (pthread_cond_destroy (&info->share->cond) |
-        pthread_mutex_destroy(&info->share->mutex))
-    {
-      DBUG_RETURN(1);
-    }
-#else
     pthread_cond_destroy (&info->share->cond);
     pthread_mutex_destroy(&info->share->mutex);
-#endif
     info->share=0;
   }
 #endif