1.2048 05/10/20 10:31:16 ingo@mysql.com +1 -0

Bug#12166 - Unable to index very large tables
Moved clearing of errors behind the second repair attempt,
but will clear only if no error happened.

No test case. The error can be repeated with little free
space on tmpdir only. I do not know of a way to create this
in a portable way with our test suite.

I did however attach a shell script to the bug report which
can easily be adapted to the situation on the test machine.

myisam/mi_check.c

@@ -1294,25 +1294,30 @@ int mi_repair(MI_CHECK *param, register MI_INFO *info,
     param->calc_checksum=1;
 
   info->update= (short) (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
+
+  /*
+    Clear all keys. Note that all key blocks allocated until now remain
+    "dead" parts of the key file. (Bug #4692)
+  */
   for (i=0 ; i < info->s->base.keys ; i++)
     share->state.key_root[i]= HA_OFFSET_ERROR;
+
+  /* Drop the delete chain. */
   for (i=0 ; i < share->state.header.max_block_size ; i++)
     share->state.key_del[i]=  HA_OFFSET_ERROR;
 
   /*
-    I think mi_repair and mi_repair_by_sort should do the same
-    (according, e.g. to ha_myisam::repair), but as mi_repair doesn't
-    touch key_map it cannot be used to T_CREATE_MISSING_KEYS.
-    That is what the next line is for
+    If requested, activate (enable) all keys in key_map. In this case,
+    all indexes will be (re-)built.
   */
-
   if (param->testflag & T_CREATE_MISSING_KEYS)
-    mi_copy_keys_active(share->state.key_map, share->base.keys,
-                        param->keys_in_use);
+    mi_set_all_keys_active(share->state.key_map, share->base.keys);
 
   info->state->key_file_length=share->base.keystart;
 
   lock_memory(param);			/* Everything is alloced */
+
+  /* Re-create all keys, which are set in key_map. */
   while (!(error=sort_get_next_record(&sort_param)))
   {
     if (writekeys(param,info,(byte*)sort_param.record,sort_param.filepos))

sql/ha_myisam.cc

@@ -985,11 +985,16 @@ int ha_myisam::enable_indexes(uint mode)
     {
       sql_print_warning("Warning: Enabling keys got errno %d, retrying",
                         my_errno);
-      thd->clear_error();
+      /* Repairing by sort failed. Now try standard repair method. */
       param.testflag&= ~(T_REP_BY_SORT | T_QUICK);
       error= (repair(thd,param,0) != HA_ADMIN_OK);
-      if (!error && thd->net.report_error)
-        error= HA_ERR_CRASHED;
+      /*
+        If the standard repair succeeded, clear all error messages which
+        might have been set by the first repair. They can still be seen
+        with SHOW WARNINGS then.
+      */
+      if (! error)
+        thd->clear_error();
     }
     info(HA_STATUS_CONST);
     thd->proc_info=save_proc_info;