WL 2826: Error handling of ALTER TABLE for partitioning

Started writing detailed error handler of
ALTER TABLE for partitioning.
Philosophical issue, should one always attempt to make recovery
automatic or should one rely on manual means also.


sql/mysql_priv.h:
  Flag to ensure we can't be killed in a very critical spot
sql/sql_base.cc:
  Flag to ensure we can't be killed in a very critical spot
sql/sql_partition.cc:
  Started writing detailed error handler of
  ALTER TABLE for partitioning.
  Philosophical issue, should one always attempt to make recovery
  automatic or should one rely on manual means also.

sql/mysql_priv.h

@@ -1218,7 +1218,8 @@ void unlock_global_table_log();
 #define WFRM_INSTALL_SHADOW 2
 #define WFRM_PACK_FRM 4
 bool mysql_write_frm(ALTER_PARTITION_PARAM_TYPE *lpt, uint flags);
-bool abort_and_upgrade_lock(ALTER_PARTITION_PARAM_TYPE *lpt);
+bool abort_and_upgrade_lock(ALTER_PARTITION_PARAM_TYPE *lpt,
+                            bool can_be_killed);
 void close_open_tables_and_downgrade(ALTER_PARTITION_PARAM_TYPE *lpt);
 void mysql_wait_completed_table(ALTER_PARTITION_PARAM_TYPE *lpt, TABLE *my_table);
 

sql/sql_base.cc

@@ -6107,7 +6107,8 @@ bool is_equal(const LEX_STRING *a, const LEX_STRING *b)
     old_lock_level                Old lock level
 */
 
-bool abort_and_upgrade_lock(ALTER_PARTITION_PARAM_TYPE *lpt)
+bool abort_and_upgrade_lock(ALTER_PARTITION_PARAM_TYPE *lpt,
+                            bool can_be_killed)
 {
   uint flags= RTFC_WAIT_OTHER_THREAD_FLAG | RTFC_CHECK_KILLED_FLAG;
   int error= FALSE;
@@ -6117,7 +6118,7 @@ bool abort_and_upgrade_lock(ALTER_PARTITION_PARAM_TYPE *lpt)
   VOID(pthread_mutex_lock(&LOCK_open));
   mysql_lock_abort(lpt->thd, lpt->table, TRUE);
   VOID(remove_table_from_cache(lpt->thd, lpt->db, lpt->table_name, flags));
-  if (lpt->thd->killed)
+  if (can_be_killed && lpt->thd->killed)
   {
     lpt->thd->no_warnings_for_error= 0;
     error= TRUE;

sql/sql_partition.cc

@@ -3910,27 +3910,6 @@ bool mysql_unpack_partition(THD *thd, const uchar *part_buf,
 }
 
 
-/*
-  SYNOPSIS
-    fast_alter_partition_error_handler()
-    lpt                           Container for parameters
-
-  RETURN VALUES
-    None
-
-  DESCRIPTION
-    Support routine to clean up after failures of on-line ALTER TABLE
-    for partition management.
-*/
-
-static void fast_alter_partition_error_handler(ALTER_PARTITION_PARAM_TYPE *lpt)
-{
-  DBUG_ENTER("fast_alter_partition_error_handler");
-  /* TODO: WL 2826 Error handling */
-  DBUG_VOID_RETURN;
-}
-
-
 /*
   SYNOPSIS
     fast_end_partition()
@@ -3952,6 +3931,7 @@ static void fast_alter_partition_error_handler(ALTER_PARTITION_PARAM_TYPE *lpt)
 
 static int fast_end_partition(THD *thd, ulonglong copied,
                               ulonglong deleted,
+                              TABLE *table,
                               TABLE_LIST *table_list, bool is_empty,
                               ALTER_PARTITION_PARAM_TYPE *lpt,
                               bool written_bin_log)
@@ -3979,7 +3959,7 @@ static int fast_end_partition(THD *thd, ulonglong copied,
     send_ok(thd,copied+deleted,0L,tmp_name);
     DBUG_RETURN(FALSE);
   }
-  fast_alter_partition_error_handler(lpt);
+  table->file->print_error(error, MYF(0));
   DBUG_RETURN(TRUE);
 }
 
@@ -4202,7 +4182,8 @@ uint prep_alter_part_table(THD *thd, TABLE *table, ALTER_INFO *alter_info,
           after the change as before. Thus we can reply ok immediately
           without any changes at all.
         */
-        DBUG_RETURN(fast_end_partition(thd, ULL(0), ULL(0), NULL,
+        DBUG_RETURN(fast_end_partition(thd, ULL(0), ULL(0),
+                                       table, NULL,
                                        TRUE, NULL, FALSE));
       }
       else if (new_part_no > curr_part_no)
@@ -5691,25 +5672,61 @@ write_log_final_change_partition(ALTER_PARTITION_PARAM_TYPE *lpt)
 */
 
 static
-bool
-write_log_completed(ALTER_PARTITION_PARAM_TYPE *lpt)
+void
+write_log_completed(ALTER_PARTITION_PARAM_TYPE *lpt, bool dont_crash)
 {
   partition_info *part_info= lpt->part_info;
+  uint count_loop= 0;
+  bool success;
   TABLE_LOG_MEMORY_ENTRY *log_entry= part_info->exec_log_entry;
   DBUG_ENTER("write_log_completed");
 
   DBUG_ASSERT(log_entry);
   lock_global_table_log();
-  if (write_execute_table_log_entry(0UL, TRUE, &log_entry))
+  do
   {
-    DBUG_RETURN(TRUE);
+    if (!(success= write_execute_table_log_entry(0UL, TRUE, &log_entry)))
+      break;
+    my_sleep(1); 
+  } while (count_loop++ < 20);
+  if (!success && !dont_crash)
+  {
+    /*
+      Failed to write 20 consecutive attempts to write. Bad...
+      We have completed the operation but have log records to REMOVE
+      stuff that shouldn't be removed. What clever things could one do
+      here?
+    */
+    abort();
   }
   release_part_info_log_entries(part_info->first_log_entry);
   release_part_info_log_entries(part_info->exec_log_entry);
   unlock_global_table_log();
   part_info->exec_log_entry= NULL;
   part_info->first_log_entry= NULL;
-  DBUG_RETURN(FALSE);
+  DBUG_VOID_RETURN;
+}
+
+
+/*
+   Release all log entries
+   SYNOPSIS
+     release_log_entries()
+     part_info                  Partition info struct
+   RETURN VALUES
+     NONE
+*/
+
+static
+void
+release_log_entries(partition *part_info)
+{
+  lock_global_table_log();
+  release_part_info_log_entries(part_info->first_log_entry);
+  release_part_info_log_entries(part_info->exec_log_entry);
+  unlock_global_table_log();
+  part_info->first_log_entry= NULL;
+  part_info->exec_log_entry= NULL;
 }
 
 
@@ -5724,36 +5741,87 @@ write_log_completed(ALTER_PARTITION_PARAM_TYPE *lpt)
 */
 
 void
-handle_alter_part_error(ALTER_PARTITION_PARAM_TYPE *lpt, bool not_completed)
+handle_alter_part_error(ALTER_PARTITION_PARAM_TYPE *lpt, bool not_completed,
+                        bool drop_partition, bool frm_install)
 {
   partition_info *part_info= lpt->part_info;
   DBUG_ENTER("handle_alter_part_error");
 
+#if 0
   if (!part_info->first_log_entry &&
       execute_table_log_entry(part_info->first_log_entry))
   {
     /*
       We couldn't recover from error
     */
+    if (not_completed)
+    {
+      if (drop_partition)
+      {
+        /* Table is still ok, but we left a shadow frm file behind. */
+        write_log_completed(lpt, TRUE);
+        release_log_entries(part_info);
+        push_warning(lpt->thd, MYSQL_ERROR::WARN_LEVEL_WARN, 1,
+"Operation was unsuccessful, table still intact, shadow frm file left behind"
+                    );
+      }
     }
     else
     {
+      if (frm_install && drop_partition)
+      {
+        /*
+           Failed during install of shadow frm file, table isn't intact
+           and dropped partitions are still there
+        */
+      }
+      else if (drop_partition)
+      {
+        /*
+          Table is ok, we have switched to new table but left dropped partitions
+          still in their places. We remove the log records and ask the user to
+          perform the action manually. We remove the log records and ask the user to
+          perform the action manually.
+        */
+        char *text1= "Failed during drop of partitions, table is intact, ";
+        char *text2= "Manual drop of remaining partitions is required";
+        write_log_completed(lpt, TRUE);
+        release_log_entries(part_info);
+        push_warning_print(lpt->thd, MYSQL_ERROR::WARN_LEVEL_WARN, 1,
+                           "%s\n%s", text1, text2);
+      }
+      else (frm_install)
+      {
+      }
+    }
+    
+  }
+  else
+  {
+    release_log_entries(part_info);
     if (not_completed)
     {
       /*
         We hit an error before things were completed but managed
-        to recover from the error.
+        to recover from the error. An error occurred and we have
+        restored things to original so no need for further action.
       */
+      ;
     }
     else
     {
       /*
         We hit an error after we had completed most of the operation
         and were successful in a second attempt so the operation
-        actually is successful now.
+        actually is successful now. We need to issue a warning that
+        even though we reported an error the operation was successfully
+        completed.
       */
+      push_warning(lpt->thd, MYSQL_ERROR::WARN_LEVEL_WARN, 1,
+      "Operation was successfully completed after failure of normal operation");
     }
   }
+#endif
   DBUG_VOID_RETURN;
 }
 
@@ -5799,6 +5867,8 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
   ALTER_PARTITION_PARAM_TYPE lpt_obj;
   ALTER_PARTITION_PARAM_TYPE *lpt= &lpt_obj;
   bool written_bin_log= TRUE;
+  bool not_completed= TRUE;
+  bool frm_install= FALSE;
   DBUG_ENTER("fast_alter_partition_table");
 
   lpt->thd= thd;
@@ -5844,7 +5914,7 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
         ((alter_info->flags & ALTER_REPAIR_PARTITION) &&
          (table->file->repair_partitions(thd))))
     {
-      fast_alter_partition_error_handler(lpt);
+      table->file->print_error(error, MYF(0));
       DBUG_RETURN(TRUE);
     }
   }
@@ -5892,7 +5962,6 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
     if (mysql_write_frm(lpt, WFRM_WRITE_SHADOW | WFRM_PACK_FRM) ||
         mysql_change_partitions(lpt))
     {
-      fast_alter_partition_error_handler(lpt);
       DBUG_RETURN(TRUE);
     }
   }
@@ -5950,7 +6019,6 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
       We insert Error injections at all places where it could be interesting
       to test if recovery is properly done.
     */
-    bool not_completed= TRUE;
     if (write_log_drop_shadow_frm(lpt) ||
         ERROR_INJECT_CRASH("crash_drop_partition_1") ||
         mysql_write_frm(lpt, WFRM_WRITE_SHADOW) ||
@@ -5958,26 +6026,25 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
         write_log_drop_partition(lpt) ||
         ERROR_INJECT_CRASH("crash_drop_partition_3") ||
         ((not_completed= FALSE), FALSE) ||
-        abort_and_upgrade_lock(lpt) ||
+        (abort_and_upgrade_lock(lpt, FALSE), FALSE) ||
         ((!thd->lex->no_write_to_binlog) &&
          (write_bin_log(thd, FALSE,
                         thd->query, thd->query_length), FALSE)) ||
         ERROR_INJECT_CRASH("crash_drop_partition_4") ||
+        (table->file->extra(HA_EXTRA_PREPARE_FOR_DELETE), FALSE) ||
+        ERROR_INJECT_CRASH("crash_drop_partition_5") ||
+        ((frm_install= TRUE), FALSE) ||
         mysql_write_frm(lpt, WFRM_INSTALL_SHADOW) ||
+        ((frm_install= FALSE), FALSE) ||
         (close_open_tables_and_downgrade(lpt), FALSE) || 
-        ERROR_INJECT_CRASH("crash_drop_partition_5") ||
-        (table->file->extra(HA_EXTRA_PREPARE_FOR_DELETE), FALSE) ||
         ERROR_INJECT_CRASH("crash_drop_partition_6") ||
         mysql_drop_partitions(lpt) ||
         ERROR_INJECT_CRASH("crash_drop_partition_7") ||
-        write_log_completed(lpt) ||
+        (write_log_completed(lpt, FALSE), FALSE) ||
         ERROR_INJECT_CRASH("crash_drop_partition_8") ||
         (mysql_wait_completed_table(lpt, table), FALSE))
     {
-      handle_alter_part_error(lpt, not_completed);
-      DBUG_RETURN(TRUE);
-      abort();
-      fast_alter_partition_error_handler(lpt);
+      handle_alter_part_error(lpt, not_completed, TRUE, frm_install);
       DBUG_RETURN(TRUE);
     }
   }
@@ -6011,14 +6078,13 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
       8) Remove entries from table log
       9) Complete query
     */
-    bool not_completed= TRUE;
     if (write_log_add_change_partition(lpt) ||
         ERROR_INJECT_CRASH("crash_add_partition_1") ||
         mysql_write_frm(lpt, WFRM_WRITE_SHADOW) ||
         ERROR_INJECT_CRASH("crash_add_partition_2") ||
         mysql_change_partitions(lpt) ||
         ERROR_INJECT_CRASH("crash_add_partition_3") ||
-        abort_and_upgrade_lock(lpt) ||
+        (abort_and_upgrade_lock(lpt, FALSE), FALSE) ||
         ((!thd->lex->no_write_to_binlog) &&
          (write_bin_log(thd, FALSE,
                         thd->query, thd->query_length), FALSE)) ||
@@ -6026,16 +6092,14 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
         write_log_rename_frm(lpt) ||
         ((not_completed= FALSE), FALSE) ||
         ERROR_INJECT_CRASH("crash_add_partition_5") ||
+        ((frm_install= TRUE), FALSE) ||
         mysql_write_frm(lpt, WFRM_INSTALL_SHADOW) ||
         ERROR_INJECT_CRASH("crash_add_partition_6") ||
         (close_open_tables_and_downgrade(lpt), FALSE) ||
-        write_log_completed(lpt) ||
+        (write_log_completed(lpt, FALSE), FALSE) ||
         ERROR_INJECT_CRASH("crash_add_partition_7")) 
     {
-      abort();
-      if (!not_completed)
-        abort();
-      fast_alter_partition_error_handler(lpt);
+      handle_alter_part_error(lpt, not_completed, FALSE, frm_install);
       DBUG_RETURN(TRUE);
     }
   }
@@ -6094,7 +6158,6 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
       13)Wait until all accesses using the old frm file has completed
       14)Complete query
     */
-    bool not_completed= TRUE;
     if (write_log_add_change_partition(lpt) ||
         ERROR_INJECT_CRASH("crash_change_partition_1") ||
         mysql_write_frm(lpt, WFRM_WRITE_SHADOW) ||
@@ -6104,7 +6167,7 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
         write_log_final_change_partition(lpt) ||
         ERROR_INJECT_CRASH("crash_change_partition_4") ||
         ((not_completed= FALSE), FALSE) ||
-        abort_and_upgrade_lock(lpt) ||
+        (abort_and_upgrade_lock(lpt, FALSE), FALSE) ||
         ((!thd->lex->no_write_to_binlog) &&
          (write_bin_log(thd, FALSE,
                         thd->query, thd->query_length), FALSE)) ||
@@ -6112,19 +6175,17 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
         (table->file->extra(HA_EXTRA_PREPARE_FOR_DELETE), FALSE) ||
         ERROR_INJECT_CRASH("crash_change_partition_6") ||
         mysql_rename_partitions(lpt) ||
+        ((frm_install= TRUE), FALSE) ||
         ERROR_INJECT_CRASH("crash_change_partition_7") ||
         mysql_write_frm(lpt, WFRM_INSTALL_SHADOW) ||
         ERROR_INJECT_CRASH("crash_change_partition_8") ||
         (close_open_tables_and_downgrade(lpt), FALSE) ||
         ERROR_INJECT_CRASH("crash_change_partition_9") ||
-        write_log_completed(lpt) ||
+        (write_log_completed(lpt, FALSE), FALSE) ||
         ERROR_INJECT_CRASH("crash_change_partition_10") ||
         (mysql_wait_completed_table(lpt, table), FALSE))
     {
-      abort();
-      if (!not_completed)
-        abort();
-      fast_alter_partition_error_handler(lpt);
+      handle_alter_part_error(lpt, not_completed, FALSE, frm_install);
       DBUG_RETURN(TRUE);
     }
   }
@@ -6133,7 +6194,7 @@ uint fast_alter_partition_table(THD *thd, TABLE *table,
     user
   */
   DBUG_RETURN(fast_end_partition(thd, lpt->copied, lpt->deleted,
-                                 table_list, FALSE, lpt,
+                                 table, table_list, FALSE, lpt,
                                  written_bin_log));
 }
 #endif