MDEV-28054 Various crashes upon INSERT/UPDATE after changing Aria settings

The cause of the crash was that test was setting
aria_sort_buffer_size to MAX_LONG_LONG, which caused an overflow in
my_malloc() when trying to allocate the buffer + 8 bytes.

Fixed by reducing max size of sort_buffer for Aria and MyISAM

Other things:
- Added code in maria_repair_parallell() to not allocate a big sort buffer
  for small files.
- Updated size of minumim sort buffer in Aria

15 files changed, 159 insertions, 62 deletions

diff --git a/mysql-test/suite/maria/maria.result b/mysql-test/suite/maria/maria.result
index 925c5121bfb..f8911bdde2b 100644
--- a/mysql-test/suite/maria/maria.result
+++ b/mysql-test/suite/maria/maria.result
@@ -2814,7 +2814,7 @@ DROP TABLE t1;
 #             cardinalities=1
 #
 SET aria_repair_threads=2;
-SET aria_sort_buffer_size=8192;
+SET aria_sort_buffer_size=16384;
 CREATE TABLE t1(a CHAR(255), KEY(a), KEY(a), KEY(a));
 Warnings:
 Note	1831	Duplicate index `a_2`. This is deprecated and will be disallowed in a future release
@@ -2839,19 +2839,8 @@ SET aria_repair_threads=@@global.aria_repair_threads;
 #             low myisam_sort_buffer_size
 #
 CREATE TABLE t1(a INT, b CHAR(10), KEY(a), KEY(b));
-INSERT INTO t1 VALUES(1,'0'),(2,'0'),(3,'0'),(4,'0'),(5,'0'),
-(6,'0'),(7,'0');
-INSERT INTO t1 SELECT a+10,b FROM t1;
-INSERT INTO t1 SELECT a+20,b FROM t1;
-INSERT INTO t1 SELECT a+40,b FROM t1;
-INSERT INTO t1 SELECT a+80,b FROM t1;
-INSERT INTO t1 SELECT a+160,b FROM t1;
-INSERT INTO t1 SELECT a+320,b FROM t1;
-INSERT INTO t1 SELECT a+640,b FROM t1;
-INSERT INTO t1 SELECT a+1280,b FROM t1;
-INSERT INTO t1 SELECT a+2560,b FROM t1;
-INSERT INTO t1 SELECT a+5120,b FROM t1;
-SET aria_sort_buffer_size=4096;
+INSERT INTO t1 select seq,'0' from seq_1_to_65536;
+SET aria_sort_buffer_size=16384;
 REPAIR TABLE t1;
 Table	Op	Msg_type	Msg_text
 test.t1	repair	error	aria_sort_buffer_size is too small. X
diff --git a/mysql-test/suite/maria/maria.test b/mysql-test/suite/maria/maria.test
index a326bb12d2a..f7a5b5c35b2 100644
--- a/mysql-test/suite/maria/maria.test
+++ b/mysql-test/suite/maria/maria.test
@@ -5,6 +5,7 @@
 
 -- source include/have_maria.inc
 -- source include/have_partition.inc
+-- source include/have_sequence.inc
 
 call mtr.add_suppression("Can't find record in '.*'");
 
@@ -2034,7 +2035,7 @@ DROP TABLE t1;
 --echo #             cardinalities=1
 --echo #
 SET aria_repair_threads=2;
-SET aria_sort_buffer_size=8192;
+SET aria_sort_buffer_size=16384;
 CREATE TABLE t1(a CHAR(255), KEY(a), KEY(a), KEY(a));
 INSERT INTO t1 VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9),(0),(1),(2),(3);
 --replace_regex /Current aria_sort_buffer_size.*/X/
@@ -2050,19 +2051,8 @@ SET aria_repair_threads=@@global.aria_repair_threads;
 --echo #             low myisam_sort_buffer_size
 --echo #
 CREATE TABLE t1(a INT, b CHAR(10), KEY(a), KEY(b));
-INSERT INTO t1 VALUES(1,'0'),(2,'0'),(3,'0'),(4,'0'),(5,'0'),
-                     (6,'0'),(7,'0');
-INSERT INTO t1 SELECT a+10,b FROM t1;
-INSERT INTO t1 SELECT a+20,b FROM t1;
-INSERT INTO t1 SELECT a+40,b FROM t1;
-INSERT INTO t1 SELECT a+80,b FROM t1;
-INSERT INTO t1 SELECT a+160,b FROM t1;
-INSERT INTO t1 SELECT a+320,b FROM t1;
-INSERT INTO t1 SELECT a+640,b FROM t1;
-INSERT INTO t1 SELECT a+1280,b FROM t1;
-INSERT INTO t1 SELECT a+2560,b FROM t1;
-INSERT INTO t1 SELECT a+5120,b FROM t1;
-SET aria_sort_buffer_size=4096;
+INSERT INTO t1 select seq,'0' from seq_1_to_65536;
+SET aria_sort_buffer_size=16384;
 --replace_regex /Current aria_sort_buffer_size.*/X/
 REPAIR TABLE t1;
 CHECK TABLE t1;
diff --git a/mysql-test/suite/maria/repair-big-sort.result b/mysql-test/suite/maria/repair-big-sort.result
new file mode 100644
index 00000000000..d1dfe3f7c2f
--- /dev/null
+++ b/mysql-test/suite/maria/repair-big-sort.result
@@ -0,0 +1,81 @@
+SET sql_mode='';
+CREATE TEMPORARY TABLE t1 (a tinyINT,b CHAR(1)) ENGINE=InnoDB ROW_FORMAT=REDUNDANT;
+INSERT INTO t1 VALUES (1,1),(3,3),(2,2);
+SET SESSION tmp_table_size=True;
+Warnings:
+Warning	1292	Truncated incorrect tmp_table_size value: '1'
+CREATE TABLE t2 (c INT, d DATE) ENGINE=InnoDB PARTITION BY RANGE (YEAR (d)) SUBPARTITION BY HASH (TO_DAYS (d)) (PARTITION p0 VALUES LESS THAN (1990) (SUBPARTITION s0, SUBPARTITION s1), PARTITION p1 VALUES LESS THAN MAXVALUE (SUBPARTITION s4, SUBPARTITION s5));
+SET SESSION aria_sort_buffer_size=CAST(-1 AS UNSIGNED INT);
+Warnings:
+Note	1105	Cast to unsigned converted negative integer to it's positive complement
+Note	1105	Cast to unsigned converted negative integer to it's positive complement
+Warning	1292	Truncated incorrect aria_sort_buffer_size value: '18446744073709551615'
+INSERT INTO t1 SELECT '', SEQ FROM seq_1_to_258;
+Warnings:
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 1
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 2
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 3
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 4
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 5
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 6
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 7
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 8
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 9
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 10
+Warning	1265	Data truncated for column 'b' at row 10
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 11
+Warning	1265	Data truncated for column 'b' at row 11
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 12
+Warning	1265	Data truncated for column 'b' at row 12
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 13
+Warning	1265	Data truncated for column 'b' at row 13
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 14
+Warning	1265	Data truncated for column 'b' at row 14
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 15
+Warning	1265	Data truncated for column 'b' at row 15
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 16
+Warning	1265	Data truncated for column 'b' at row 16
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 17
+Warning	1265	Data truncated for column 'b' at row 17
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 18
+Warning	1265	Data truncated for column 'b' at row 18
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 19
+Warning	1265	Data truncated for column 'b' at row 19
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 20
+Warning	1265	Data truncated for column 'b' at row 20
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 21
+Warning	1265	Data truncated for column 'b' at row 21
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 22
+Warning	1265	Data truncated for column 'b' at row 22
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 23
+Warning	1265	Data truncated for column 'b' at row 23
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 24
+Warning	1265	Data truncated for column 'b' at row 24
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 25
+Warning	1265	Data truncated for column 'b' at row 25
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 26
+Warning	1265	Data truncated for column 'b' at row 26
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 27
+Warning	1265	Data truncated for column 'b' at row 27
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 28
+Warning	1265	Data truncated for column 'b' at row 28
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 29
+Warning	1265	Data truncated for column 'b' at row 29
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 30
+Warning	1265	Data truncated for column 'b' at row 30
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 31
+Warning	1265	Data truncated for column 'b' at row 31
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 32
+Warning	1265	Data truncated for column 'b' at row 32
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 33
+Warning	1265	Data truncated for column 'b' at row 33
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 34
+Warning	1265	Data truncated for column 'b' at row 34
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 35
+Warning	1265	Data truncated for column 'b' at row 35
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 36
+Warning	1265	Data truncated for column 'b' at row 36
+Warning	1366	Incorrect integer value: '' for column `test`.`t1`.`a` at row 37
+SET SESSION aria_repair_threads=4;
+UPDATE t1 SET a=( (SELECT MAX(a) FROM t1));
+drop table t1,t2;
diff --git a/mysql-test/suite/maria/repair-big-sort.test b/mysql-test/suite/maria/repair-big-sort.test
new file mode 100644
index 00000000000..f2f4f84c29b
--- /dev/null
+++ b/mysql-test/suite/maria/repair-big-sort.test
@@ -0,0 +1,15 @@
+
+--source include/have_innodb.inc
+--source include/have_partition.inc
+--source include/have_sequence.inc
+
+SET sql_mode='';
+CREATE TEMPORARY TABLE t1 (a tinyINT,b CHAR(1)) ENGINE=InnoDB ROW_FORMAT=REDUNDANT;
+INSERT INTO t1 VALUES (1,1),(3,3),(2,2);
+SET SESSION tmp_table_size=True;
+CREATE TABLE t2 (c INT, d DATE) ENGINE=InnoDB PARTITION BY RANGE (YEAR (d)) SUBPARTITION BY HASH (TO_DAYS (d)) (PARTITION p0 VALUES LESS THAN (1990) (SUBPARTITION s0, SUBPARTITION s1), PARTITION p1 VALUES LESS THAN MAXVALUE (SUBPARTITION s4, SUBPARTITION s5));
+SET SESSION aria_sort_buffer_size=CAST(-1 AS UNSIGNED INT);
+INSERT INTO t1 SELECT '', SEQ FROM seq_1_to_258;
+SET SESSION aria_repair_threads=4;
+UPDATE t1 SET a=( (SELECT MAX(a) FROM t1));
+drop table t1,t2;
diff --git a/mysql-test/suite/sys_vars/r/aria_sort_buffer_size_basic.result b/mysql-test/suite/sys_vars/r/aria_sort_buffer_size_basic.result
index 56522566ec9..6da4c9bfe97 100644
--- a/mysql-test/suite/sys_vars/r/aria_sort_buffer_size_basic.result
+++ b/mysql-test/suite/sys_vars/r/aria_sort_buffer_size_basic.result
@@ -22,13 +22,13 @@ Warnings:
 Warning	1292	Truncated incorrect aria_sort_buffer_size value: '10'
 select @@global.aria_sort_buffer_size;
 @@global.aria_sort_buffer_size
-4096
+16376
 set session aria_sort_buffer_size=10;
 Warnings:
 Warning	1292	Truncated incorrect aria_sort_buffer_size value: '10'
 select @@session.aria_sort_buffer_size;
 @@session.aria_sort_buffer_size
-4096
+16376
 set global aria_sort_buffer_size=1.1;
 ERROR 42000: Incorrect argument type to variable 'aria_sort_buffer_size'
 set session aria_sort_buffer_size=1e1;
@@ -40,9 +40,9 @@ Warnings:
 Warning	1292	Truncated incorrect aria_sort_buffer_size value: '0'
 select @@global.aria_sort_buffer_size;
 @@global.aria_sort_buffer_size
-4096
+16376
 set session aria_sort_buffer_size=cast(-1 as unsigned int);
 select @@session.aria_sort_buffer_size;
 @@session.aria_sort_buffer_size
-18446744073709551615
+1152921504606846975
 SET @@global.aria_sort_buffer_size = @start_global_value;
diff --git a/mysql-test/suite/sys_vars/r/sysvars_aria.result b/mysql-test/suite/sys_vars/r/sysvars_aria.result
index 9f5585668b6..3e9130db9db 100644
--- a/mysql-test/suite/sys_vars/r/sysvars_aria.result
+++ b/mysql-test/suite/sys_vars/r/sysvars_aria.result
@@ -223,8 +223,8 @@ DEFAULT_VALUE	268434432
 VARIABLE_SCOPE	SESSION
 VARIABLE_TYPE	BIGINT UNSIGNED
 VARIABLE_COMMENT	The buffer that is allocated when sorting the index when doing a REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE.
-NUMERIC_MIN_VALUE	4096
-NUMERIC_MAX_VALUE	18446744073709551615
+NUMERIC_MIN_VALUE	16376
+NUMERIC_MAX_VALUE	1152921504606846975
 NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
diff --git a/mysql-test/suite/sys_vars/r/sysvars_server_embedded,32bit.rdiff b/mysql-test/suite/sys_vars/r/sysvars_server_embedded,32bit.rdiff
index e0aad7fa6d0..6fa25546ad1 100644
--- a/mysql-test/suite/sys_vars/r/sysvars_server_embedded,32bit.rdiff
+++ b/mysql-test/suite/sys_vars/r/sysvars_server_embedded,32bit.rdiff
@@ -97,9 +97,9 @@
 @@ -207,7 +207,7 @@ VARIABLE_SCOPE	SESSION
  VARIABLE_TYPE	BIGINT UNSIGNED
  VARIABLE_COMMENT	The buffer that is allocated when sorting the index when doing a REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE.
- NUMERIC_MIN_VALUE	4096
+ NUMERIC_MIN_VALUE	16376
 -NUMERIC_MAX_VALUE	18446744073709551615
-+NUMERIC_MAX_VALUE	4294967295
++NUMERIC_MAX_VALUE	268435455
  NUMERIC_BLOCK_SIZE	1
  ENUM_VALUE_LIST	NULL
  READ_ONLY	NO
@@ -684,8 +684,8 @@
  VARIABLE_TYPE	BIGINT UNSIGNED
  VARIABLE_COMMENT	The buffer that is allocated when sorting the index when doing a REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE
  NUMERIC_MIN_VALUE	4096
--NUMERIC_MAX_VALUE	18446744073709551615
-+NUMERIC_MAX_VALUE	4294967295
+-NUMERIC_MAX_VALUE	1152921504606846975
++NUMERIC_MAX_VALUE	268435455
  NUMERIC_BLOCK_SIZE	1
  ENUM_VALUE_LIST	NULL
  READ_ONLY	NO
diff --git a/mysql-test/suite/sys_vars/r/sysvars_server_embedded.result b/mysql-test/suite/sys_vars/r/sysvars_server_embedded.result
index 1ed5b5ce3bd..c03181d0c63 100644
--- a/mysql-test/suite/sys_vars/r/sysvars_server_embedded.result
+++ b/mysql-test/suite/sys_vars/r/sysvars_server_embedded.result
@@ -216,8 +216,8 @@ VARIABLE_NAME	ARIA_SORT_BUFFER_SIZE
 VARIABLE_SCOPE	SESSION
 VARIABLE_TYPE	BIGINT UNSIGNED
 VARIABLE_COMMENT	The buffer that is allocated when sorting the index when doing a REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE.
-NUMERIC_MIN_VALUE	4096
-NUMERIC_MAX_VALUE	18446744073709551615
+NUMERIC_MIN_VALUE	16376
+NUMERIC_MAX_VALUE	1152921504606846975
 NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
@@ -2127,7 +2127,7 @@ VARIABLE_SCOPE	SESSION
 VARIABLE_TYPE	BIGINT UNSIGNED
 VARIABLE_COMMENT	The buffer that is allocated when sorting the index when doing a REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE
 NUMERIC_MIN_VALUE	4096
-NUMERIC_MAX_VALUE	18446744073709551615
+NUMERIC_MAX_VALUE	1152921504606846975
 NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
diff --git a/mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result b/mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result
index 125d629ac87..48b481b200c 100644
--- a/mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result
+++ b/mysql-test/suite/sys_vars/r/sysvars_server_notembedded.result
@@ -216,8 +216,8 @@ VARIABLE_NAME	ARIA_SORT_BUFFER_SIZE
 VARIABLE_SCOPE	SESSION
 VARIABLE_TYPE	BIGINT UNSIGNED
 VARIABLE_COMMENT	The buffer that is allocated when sorting the index when doing a REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE.
-NUMERIC_MIN_VALUE	4096
-NUMERIC_MAX_VALUE	18446744073709551615
+NUMERIC_MIN_VALUE	16376
+NUMERIC_MAX_VALUE	1152921504606846975
 NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
@@ -2287,7 +2287,7 @@ VARIABLE_SCOPE	SESSION
 VARIABLE_TYPE	BIGINT UNSIGNED
 VARIABLE_COMMENT	The buffer that is allocated when sorting the index when doing a REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE
 NUMERIC_MIN_VALUE	4096
-NUMERIC_MAX_VALUE	18446744073709551615
+NUMERIC_MAX_VALUE	1152921504606846975
 NUMERIC_BLOCK_SIZE	1
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO
diff --git a/storage/maria/ha_maria.cc b/storage/maria/ha_maria.cc
index f25ba2aa0b3..6639fc39caf 100644
--- a/storage/maria/ha_maria.cc
+++ b/storage/maria/ha_maria.cc
@@ -269,7 +269,7 @@ static MYSQL_THDVAR_ULONG(repair_threads, PLUGIN_VAR_RQCMDARG,
 static MYSQL_THDVAR_ULONGLONG(sort_buffer_size, PLUGIN_VAR_RQCMDARG,
        "The buffer that is allocated when sorting the index when doing a "
        "REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE.", NULL, NULL,
-       SORT_BUFFER_INIT, MIN_SORT_BUFFER, SIZE_T_MAX, 1);
+       SORT_BUFFER_INIT, MARIA_MIN_SORT_MEMORY, SIZE_T_MAX/16, 1);
 
 static MYSQL_THDVAR_ENUM(stats_method, PLUGIN_VAR_RQCMDARG,
        "Specifies how Aria index statistics collection code should treat "
diff --git a/storage/maria/ma_check.c b/storage/maria/ma_check.c
index fec443dfc56..6835af928ee 100644
--- a/storage/maria/ma_check.c
+++ b/storage/maria/ma_check.c
@@ -3903,6 +3903,16 @@ int maria_repair_by_sort(HA_CHECK *param, register MARIA_HA *info,
     {
       sort_param.key_read=  sort_key_read;
       sort_param.key_write= sort_key_write;
+
+      /*
+        Limit usage of sort memory
+        We assume we don't need more memory than data file length * 2
+        (There is a pointer overhead for each key, but this is hard to
+        estimae as we cannot be sure how many records we have in file to
+        be repaired).
+      */
+      set_if_smaller(param->sort_buffer_length, sort_info.filelength*2);
+      set_if_bigger(param->sort_buffer_length, MARIA_MIN_SORT_MEMORY);
     }
 
     if (sort_info.new_info->s->data_file_type == BLOCK_RECORD)
@@ -4506,6 +4516,16 @@ int maria_repair_parallel(HA_CHECK *param, register MARIA_HA *info,
                                   i, &sort_param[i].read_cache));
 
     /*
+      Limit usage of sort memory
+      We assume we don't need more memory than data file length * 2
+      (There is a pointer overhead for each key, but this is hard to
+      estimae as we cannot be sure how many records we have in file to
+      be repaired).
+     */
+    set_if_smaller(param->sort_buffer_length, sort_info.filelength*2);
+    set_if_bigger(param->sort_buffer_length, MARIA_MIN_SORT_MEMORY);
+
+    /*
       two approaches: the same amount of memory for each thread
       or the memory for the same number of keys for each thread...
       In the second one all the threads will fill their sort_buffers
@@ -4517,6 +4537,8 @@ int maria_repair_parallel(HA_CHECK *param, register MARIA_HA *info,
 #else
       param->sort_buffer_length*sort_param[i].key_length/total_key_length;
 #endif
+    set_if_bigger(sort_param[i].sortbuff_size, MARIA_MIN_SORT_MEMORY);
+
     if (mysql_thread_create(key_thread_find_all_keys,
                             &sort_param[i].thr, &thr_attr,
 	                    _ma_thr_find_all_keys, (void *) (sort_param+i)))
diff --git a/storage/maria/ma_sort.c b/storage/maria/ma_sort.c
index 4dc6472bd15..bd57cdb7727 100644
--- a/storage/maria/ma_sort.c
+++ b/storage/maria/ma_sort.c
@@ -29,12 +29,10 @@
 
 /* static variables */
 
-#undef MIN_SORT_MEMORY
 #undef DISK_BUFFER_SIZE
 
 #define MERGEBUFF 15
 #define MERGEBUFF2 31
-#define MIN_SORT_MEMORY (4096-MALLOC_OVERHEAD)
 #define DISK_BUFFER_SIZE (IO_SIZE*128)
 
 /* How many keys we can keep in memory */
@@ -145,11 +143,11 @@ int _ma_create_index_by_sort(MARIA_SORT_PARAM *info, my_bool no_messages,
   sort_keys= (uchar **) NULL; error= 1;
   maxbuffer=1;
 
-  memavl=MY_MAX(sortbuff_size,MIN_SORT_MEMORY);
+  memavl=MY_MAX(sortbuff_size,MARIA_MIN_SORT_MEMORY);
   records=	info->sort_info->max_records;
   sort_length=	info->key_length;
 
-  while (memavl >= MIN_SORT_MEMORY)
+  while (memavl >= MARIA_MIN_SORT_MEMORY)
   {
     /* Check if we can fit all keys into memory */
     if (((ulonglong) (records + 1) *
@@ -208,10 +206,10 @@ int _ma_create_index_by_sort(MARIA_SORT_PARAM *info, my_bool no_messages,
 	break;
     }
     old_memavl=memavl;
-    if ((memavl=memavl/4*3) < MIN_SORT_MEMORY && old_memavl > MIN_SORT_MEMORY)
-      memavl=MIN_SORT_MEMORY;
+    if ((memavl=memavl/4*3) < MARIA_MIN_SORT_MEMORY && old_memavl > MARIA_MIN_SORT_MEMORY)
+      memavl=MARIA_MIN_SORT_MEMORY;
   }
-  if (memavl < MIN_SORT_MEMORY)
+  if (memavl < MARIA_MIN_SORT_MEMORY)
   {
     /* purecov: begin inspected */
     _ma_check_print_error(info->sort_info->param,
@@ -387,12 +385,12 @@ static my_bool _ma_thr_find_all_keys_exec(MARIA_SORT_PARAM* sort_param)
   bzero((char*) &sort_param->unique, sizeof(sort_param->unique));
 
   sortbuff_size= sort_param->sortbuff_size;
-  memavl=       MY_MAX(sortbuff_size, MIN_SORT_MEMORY);
+  memavl=       MY_MAX(sortbuff_size, MARIA_MIN_SORT_MEMORY);
   idx=          (ha_keys) sort_param->sort_info->max_records;
   sort_length=  sort_param->key_length;
   maxbuffer=    1;
 
-  while (memavl >= MIN_SORT_MEMORY)
+  while (memavl >= MARIA_MIN_SORT_MEMORY)
   {
     if ((my_off_t) (idx+1)*(sort_length+sizeof(char*)) <= (my_off_t) memavl)
       keys= idx+1;
@@ -442,11 +440,11 @@ static my_bool _ma_thr_find_all_keys_exec(MARIA_SORT_PARAM* sort_param)
         break;
     }
     old_memavl= memavl;
-    if ((memavl= memavl/4*3) < MIN_SORT_MEMORY &&
-        old_memavl > MIN_SORT_MEMORY)
-      memavl= MIN_SORT_MEMORY;
+    if ((memavl= memavl/4*3) < MARIA_MIN_SORT_MEMORY &&
+        old_memavl > MARIA_MIN_SORT_MEMORY)
+      memavl= MARIA_MIN_SORT_MEMORY;
   }
-  if (memavl < MIN_SORT_MEMORY)
+  if (memavl < MARIA_MIN_SORT_MEMORY)
   {
     /* purecov: begin inspected */
     _ma_check_print_error(sort_param->sort_info->param,
@@ -626,7 +624,7 @@ int _ma_thr_write_keys(MARIA_SORT_PARAM *sort_param)
       if (!mergebuf)
       {
         length=(size_t)param->sort_buffer_length;
-        while (length >= MIN_SORT_MEMORY)
+        while (length >= MARIA_MIN_SORT_MEMORY)
         {
           if ((mergebuf= my_malloc((size_t) length, MYF(0))))
               break;
diff --git a/storage/maria/maria_chk.c b/storage/maria/maria_chk.c
index 2f130de1c7a..921751030a8 100644
--- a/storage/maria/maria_chk.c
+++ b/storage/maria/maria_chk.c
@@ -424,7 +424,8 @@ static struct my_option my_long_options[] =
     "Size of sort buffer. Used by --recover",
     &check_param.sort_buffer_length,
     &check_param.sort_buffer_length, 0, GET_ULL, REQUIRED_ARG,
-    SORT_BUFFER_INIT, MIN_SORT_BUFFER, SIZE_T_MAX, MALLOC_OVERHEAD, 1L, 0},
+    SORT_BUFFER_INIT, MARIA_MIN_SORT_MEMORY, SIZE_T_MAX/10, MALLOC_OVERHEAD,
+    1L, 0},
   { "sort_key_blocks", OPT_SORT_KEY_BLOCKS,
     "Internal buffer for sorting keys; Don't touch :)",
     &check_param.sort_key_blocks,
diff --git a/storage/maria/maria_def.h b/storage/maria/maria_def.h
index 80c57ad9a0e..f4799eef379 100644
--- a/storage/maria/maria_def.h
+++ b/storage/maria/maria_def.h
@@ -45,6 +45,8 @@
 #define MARIA_MAX_TREE_LEVELS 32
 #define MARIA_MAX_RECORD_ON_STACK 16384
 
+#define MARIA_MIN_SORT_MEMORY (16384-MALLOC_OVERHEAD)
+
 /* maria_open() flag, specific for maria_pack */
 #define HA_OPEN_IGNORE_MOVED_STATE (1U << 30)
 
@@ -1273,7 +1275,6 @@ typedef struct st_maria_block_info
 #define PAGE_BUFFER_INIT	MY_ALIGN_DOWN(1024L*1024L*256L-MALLOC_OVERHEAD, 8192)
 #define READ_BUFFER_INIT	MY_ALIGN_DOWN(1024L*256L-MALLOC_OVERHEAD, 1024)
 #define SORT_BUFFER_INIT	MY_ALIGN_DOWN(1024L*1024L*256L-MALLOC_OVERHEAD, 1024)
-#define MIN_SORT_BUFFER		4096U
 
 #define fast_ma_writeinfo(INFO) if (!(INFO)->s->tot_locks) (void) _ma_writeinfo((INFO),0)
 #define fast_ma_readinfo(INFO) ((INFO)->lock_type == F_UNLCK) && _ma_readinfo((INFO),F_RDLCK,1)
diff --git a/storage/myisam/ha_myisam.cc b/storage/myisam/ha_myisam.cc
index 4fef809f4f0..ddab8bcf741 100644
--- a/storage/myisam/ha_myisam.cc
+++ b/storage/myisam/ha_myisam.cc
@@ -80,7 +80,7 @@ static MYSQL_THDVAR_ULONG(repair_threads, PLUGIN_VAR_RQCMDARG,
 static MYSQL_THDVAR_ULONGLONG(sort_buffer_size, PLUGIN_VAR_RQCMDARG,
   "The buffer that is allocated when sorting the index when doing "
   "a REPAIR or when creating indexes with CREATE INDEX or ALTER TABLE", NULL, NULL,
-  SORT_BUFFER_INIT, MIN_SORT_BUFFER, SIZE_T_MAX, 1);
+  SORT_BUFFER_INIT, MIN_SORT_BUFFER, SIZE_T_MAX/16, 1);
 
 static MYSQL_SYSVAR_BOOL(use_mmap, opt_myisam_use_mmap, PLUGIN_VAR_NOCMDARG,
   "Use memory mapping for reading and writing MyISAM tables", NULL, NULL, FALSE);