BUG#51307 - widespread corruption with partitions and

            insert...select

Queries following bulk insert into an empty MyISAM table
may break it. This was pure MyISAM problem.

When bulk insert into an empty table is complete, MyISAM
may want to enable indexes via repair by sort. If repair
by sort fails (e.g. insufficient buffer), MyISAM failover
to repair with key cache, requesting repair of data file.

Repair of data file performs data file substitution. This
means that current table instance will point to new data
file. Other cached table instances are still pointing to
an old, deleted data file.

This is fixed by not requesting repair of data file
during enable indexes.

Explicit REPAIR is not affected, since it flushes all
table instances.

mysql-test/r/myisam.result:
  A test case for BUG#51307.
mysql-test/t/myisam.test:
  A test case for BUG#51307.
storage/myisam/ha_myisam.cc:
  When enabling indexes do not attempt to repair data file.

mysql-test/r/myisam.result

@@ -2339,4 +2339,37 @@ CHECK TABLE t1;
 Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
 DROP TABLE t1;
+#
+# BUG#51307 - widespread corruption with partitions and insert...select
+#
+CREATE TABLE t1(a CHAR(255), KEY(a));
+SELECT * FROM t1, t1 AS a1;
+a	a
+SET myisam_sort_buffer_size=4;
+INSERT INTO t1 VALUES
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0');
+Warnings:
+Error	1034	myisam_sort_buffer_size is too small
+Error	1034	Number of rows changed from 0 to 157
+SET myisam_sort_buffer_size=@@global.myisam_sort_buffer_size;
+INSERT INTO t1 VALUES('1');
+SELECT * FROM t1, t1 AS a1 WHERE t1.a=1 AND a1.a=1;
+a	a
+1	1
+DROP TABLE t1;
 End of 5.1 tests

mysql-test/t/myisam.test

@@ -1587,5 +1587,33 @@ REPLACE INTO t1 VALUES
 CHECK TABLE t1;
 DROP TABLE t1;
 
+--echo #
+--echo # BUG#51307 - widespread corruption with partitions and insert...select
+--echo #
+CREATE TABLE t1(a CHAR(255), KEY(a));
+SELECT * FROM t1, t1 AS a1;
+SET myisam_sort_buffer_size=4;
+INSERT INTO t1 VALUES
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),('0'),
+('0'),('0'),('0'),('0'),('0'),('0'),('0');
+SET myisam_sort_buffer_size=@@global.myisam_sort_buffer_size;
+INSERT INTO t1 VALUES('1');
+SELECT * FROM t1, t1 AS a1 WHERE t1.a=1 AND a1.a=1;
+DROP TABLE t1;
+
 --echo End of 5.1 tests
 

storage/myisam/ha_myisam.cc

@@ -1448,9 +1448,17 @@ int ha_myisam::enable_indexes(uint mode)
     {
       sql_print_warning("Warning: Enabling keys got errno %d on %s.%s, retrying",
                         my_errno, param.db_name, param.table_name);
-      /* Repairing by sort failed. Now try standard repair method. */
-      param.testflag&= ~(T_REP_BY_SORT | T_QUICK);
+      /*
+        Repairing by sort failed. Now try standard repair method.
+        Still we want to fix only index file. If data file corruption
+        was detected (T_RETRY_WITHOUT_QUICK), we shouldn't do much here.
+        Let implicit repair do this job.
+      */
+      if (!(param.testflag & T_RETRY_WITHOUT_QUICK))
+      {
+        param.testflag&= ~T_REP_BY_SORT;
         error= (repair(thd,param,0) != HA_ADMIN_OK);
+      }
       /*
         If the standard repair succeeded, clear all error messages which
         might have been set by the first repair. They can still be seen