Fix bug #11946, truncate not always resetting the auto-increment counter

in InnoDB tables.


mysql-test/r/innodb.result:
  New tests.
mysql-test/t/innodb.test:
  New tests.
sql/ha_innodb.cc:
  Add reset_auto_increment.
sql/ha_innodb.h:
  Add reset_auto_increment.
sql/handler.h:
  Add reset_auto_increment.
sql/sql_delete.cc:
  Call handler->reset_auto_increment when needed.

1 files changed, 22 insertions, 0 deletions

diff --git a/sql/sql_delete.cc b/sql/sql_delete.cc
index 35183fc959b..f6fb5f2cf53 100644
--- a/sql/sql_delete.cc
+++ b/sql/sql_delete.cc
@@ -103,6 +103,13 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
     free_underlaid_joins(thd, select_lex);
     thd->row_count_func= 0;
     send_ok(thd,0L);
+
+    /*
+      We don't need to call reset_auto_increment in this case, because
+      mysql_truncate always gives a NULL conds argument, hence we never
+      get here.
+    */
+
     DBUG_RETURN(0);				// Nothing to delete
   }
 
@@ -226,6 +233,21 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
   if (options & OPTION_QUICK)
     (void) table->file->extra(HA_EXTRA_NORMAL);
 
+  if ((error < 0) && (thd->lex->sql_command == SQLCOM_TRUNCATE))
+  {
+    /*
+      We're really doing a truncate and need to reset the table's
+      auto-increment counter.
+    */
+    int error2 = table->file->reset_auto_increment();
+
+    if (error2 && (error2 != HA_ERR_WRONG_COMMAND))
+    {
+      table->file->print_error(error2, MYF(0));
+      error = 1;
+    }
+  }
+
 cleanup:
   /*
     Invalidate the table in the query cache if something changed. This must