BUG#11756869 - 48848: MYISAMCHK DOING SORT RECOVER IN CERTAIN

                      CASES RESETS DATA POINTER TO SMAL

ISSUE: Myisamchk doing sort recover
       on a table reduces data_file_length.
       Maximum size of data file decreases,
       lesser number of rows are stored.

SOLUTION: Size of data_file_length is
          fixed to the original length.

mysql-test/r/myisam.result

@@ -2412,4 +2412,17 @@ CARDINALITY
 DROP TABLE t1;
 SET myisam_sort_buffer_size=@@global.myisam_sort_buffer_size;
 SET myisam_repair_threads=@@global.myisam_repair_threads;
+#
+# BUG 11756869 - 48848: MYISAMCHK DOING SORT RECOVER IN CERTAIN
+#                       CASES RESETS DATA POINTER TO SMAL
+#
+CREATE TABLE t1(a INT, KEY(a));
+ALTER TABLE t1 DISABLE KEYS;
+SET @before:= (SELECT MAX_DATA_LENGTH FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='t1' AND TABLE_SCHEMA='test');
+FLUSH TABLES;
+SET @after:= (SELECT MAX_DATA_LENGTH FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='t1' AND TABLE_SCHEMA='test');
+SELECT @before=@after;
+@before=@after
+1
+DROP TABLE t1;
 End of 5.1 tests

mysql-test/t/myisam.test

@@ -1645,4 +1645,20 @@ DROP TABLE t1;
 SET myisam_sort_buffer_size=@@global.myisam_sort_buffer_size;
 SET myisam_repair_threads=@@global.myisam_repair_threads;
 
+--echo #
+--echo # BUG 11756869 - 48848: MYISAMCHK DOING SORT RECOVER IN CERTAIN
+--echo #                       CASES RESETS DATA POINTER TO SMAL
+--echo #
+
+CREATE TABLE t1(a INT, KEY(a));
+ALTER TABLE t1 DISABLE KEYS;
+let $MYSQLD_DATADIR= `select @@datadir`;
+SET @before:= (SELECT MAX_DATA_LENGTH FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='t1' AND TABLE_SCHEMA='test');
+FLUSH TABLES;
+--replace_result $MYSQLD_DATADIR MYSQLD_DATADIR
+--exec $MYISAMCHK -sn $MYSQLD_DATADIR/test/t1
+SET @after:= (SELECT MAX_DATA_LENGTH FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME='t1' AND TABLE_SCHEMA='test');
+SELECT @before=@after;
+DROP TABLE t1;
+
 --echo End of 5.1 tests

storage/myisam/mi_check.c

@@ -4314,13 +4314,6 @@ int recreate_table(MI_CHECK *param, MI_INFO **org_info, char *filename)
     u_ptr->seg=keyseg;
     keyseg+=u_ptr->keysegs+1;
   }
-  if (share.options & HA_OPTION_COMPRESS_RECORD)
-    share.base.records=max_records=info.state->records;
-  else if (share.base.min_pack_length)
-    max_records=(ha_rows) (my_seek(info.dfile,0L,MY_SEEK_END,MYF(0)) /
-			   (ulong) share.base.min_pack_length);
-  else
-    max_records=0;
   unpack= (share.options & HA_OPTION_COMPRESS_RECORD) &&
     (param->testflag & T_UNPACK);
   share.options&= ~HA_OPTION_TEMP_COMPRESS_RECORD;
@@ -4330,10 +4323,17 @@ int recreate_table(MI_CHECK *param, MI_INFO **org_info, char *filename)
   set_if_bigger(file_length,param->max_data_file_length);
   set_if_bigger(file_length,tmp_length);
   set_if_bigger(file_length,(ulonglong) share.base.max_data_file_length);
+ 
+  if (share.options & HA_OPTION_COMPRESS_RECORD)
+    share.base.records=max_records=info.state->records;
+  else if (!(share.options & HA_OPTION_PACK_RECORD))
+    max_records= (ha_rows) (file_length / share.base.pack_reclength);
+  else
+    max_records= 0;
 
   VOID(mi_close(*org_info));
   bzero((char*) &create_info,sizeof(create_info));
-  create_info.max_rows=max(max_records,share.base.records);
+  create_info.max_rows= max_records;
   create_info.reloc_rows=share.base.reloc;
   create_info.old_options=(share.options |
 			   (unpack ? HA_OPTION_TEMP_COMPRESS_RECORD : 0));