Fixed bug in aria_chk that overwrote sort_buffer_length

This bug happens when one runs aria_chk on multiple tables. It does not
affect REPAIR TABLE.
aria_chk tries to optimize the sort buffer size to minimize memory usage
when used with small tables. The bug was that the adjusted value was
used as a base for the next table, which could cause problems.

include/myisamchk.h

@@ -87,7 +87,7 @@ typedef struct st_handler_check_param
   /* Following is used to check if rows are visible */
   ulonglong max_trid, max_found_trid;
   ulonglong not_visible_rows_found;
-  ulonglong sort_buffer_length;
+  ulonglong sort_buffer_length, orig_sort_buffer_length;
   ulonglong use_buffers;                        /* Used as param to getopt() */
   size_t read_buffer_length, write_buffer_length, sort_key_blocks;
   time_t backup_time;                           /* To sign backup files */

storage/maria/aria_chk.c

@@ -434,8 +434,8 @@ static struct my_option my_long_options[] =
     ~0UL, (long) MALLOC_OVERHEAD, (long) 1L, 0},
   { "sort_buffer_size", OPT_SORT_BUFFER_SIZE,
     "Size of sort buffer. Used by --recover",
-    &check_param.sort_buffer_length,
-    &check_param.sort_buffer_length, 0, GET_ULL, REQUIRED_ARG,
+    &check_param.orig_sort_buffer_length,
+    &check_param.orig_sort_buffer_length, 0, GET_ULL, REQUIRED_ARG,
     SORT_BUFFER_INIT, MIN_SORT_BUFFER, SIZE_T_MAX, MALLOC_OVERHEAD, 1L, 0},
   { "sort_key_blocks", OPT_SORT_KEY_BLOCKS,
     "Internal buffer for sorting keys; Don't touch :)",

storage/maria/ha_maria.cc

@@ -1481,7 +1481,7 @@ int ha_maria::repair(THD * thd, HA_CHECK_OPT *check_opt)
   param->testflag= ((check_opt->flags & ~(T_EXTEND)) |
                    T_SILENT | T_FORCE_CREATE | T_CALC_CHECKSUM |
                    (check_opt->flags & T_EXTEND ? T_REP : T_REP_BY_SORT));
-  param->sort_buffer_length= THDVAR(thd, sort_buffer_size);
+  param->orig_sort_buffer_length= THDVAR(thd, sort_buffer_size);
   param->backup_time= check_opt->start_time;
   start_records= file->state->records;
   old_proc_info= thd_proc_info(thd, "Checking table");
@@ -1552,7 +1552,7 @@ int ha_maria::zerofill(THD * thd, HA_CHECK_OPT *check_opt)
   param->thd= thd;
   param->op_name= "zerofill";
   param->testflag= check_opt->flags | T_SILENT | T_ZEROFILL;
-  param->sort_buffer_length= THDVAR(thd, sort_buffer_size);
+  param->orig_sort_buffer_length= THDVAR(thd, sort_buffer_size);
   param->db_name= table->s->db.str;
   param->table_name= table->alias.c_ptr();
 
@@ -1588,7 +1588,7 @@ int ha_maria::optimize(THD * thd, HA_CHECK_OPT *check_opt)
   param->op_name= "optimize";
   param->testflag= (check_opt->flags | T_SILENT | T_FORCE_CREATE |
                    T_REP_BY_SORT | T_STATISTICS | T_SORT_INDEX);
-  param->sort_buffer_length= THDVAR(thd, sort_buffer_size);
+  param->orig_sort_buffer_length= THDVAR(thd, sort_buffer_size);
   thd_progress_init(thd, 1);
   if ((error= repair(thd, param, 1)) && param->retry_repair)
   {
@@ -2056,7 +2056,7 @@ int ha_maria::enable_indexes(uint mode)
     }
 
     param->myf_rw &= ~MY_WAIT_IF_FULL;
-    param->sort_buffer_length= THDVAR(thd,sort_buffer_size);
+    param->orig_sort_buffer_length= THDVAR(thd,sort_buffer_size);
     param->stats_method= (enum_handler_stats_method)THDVAR(thd,stats_method);
     param->tmpdir= &mysql_tmpdir_list;
     if ((error= (repair(thd, param, 0) != HA_ADMIN_OK)) && param->retry_repair)

storage/maria/ma_check.c

@@ -114,7 +114,7 @@ void maria_chk_init(HA_CHECK *param)
   param->use_buffers= PAGE_BUFFER_INIT;
   param->read_buffer_length=READ_BUFFER_INIT;
   param->write_buffer_length=READ_BUFFER_INIT;
-  param->sort_buffer_length=SORT_BUFFER_INIT;
+  param->orig_sort_buffer_length=SORT_BUFFER_INIT;
   param->sort_key_blocks=BUFFERS_WHEN_SORTING;
   param->tmpfile_createflag=O_RDWR | O_TRUNC | O_EXCL;
   param->myf_rw=MYF(MY_NABP | MY_WME | MY_WAIT_IF_FULL);
@@ -2483,6 +2483,8 @@ static int initialize_variables_for_repair(HA_CHECK *param,
   tmp= (size_t) MY_MIN(sort_info->filelength,
                        (my_off_t) (SIZE_T_MAX/10/threads));
   tmp= MY_MAX(tmp * 8 * threads, (size_t) 65536);         /* Some margin */
+  param->sort_buffer_length= MY_MIN(param->orig_sort_buffer_length,
+                                    tmp);
   set_if_smaller(param->sort_buffer_length, tmp);
   /* Protect against too big sort buffer length */
 #if SIZEOF_SIZE_T >= 8