Reducing memory when using information schema

The background is that one user had a lot of views and using some complex
queries on information schema temporary memory of more than 2G was used.

- Added new element 'total_alloc' to MEM_ROOT for easier debugging.
- Added MAX_MEMORY_USED to information_schema.processlist.
- Added new status variable "Memory_used_initial" that shows how much MariaDB
  uses at startup. This gives the base value for "Memory_used".
- Reuse memory continuously for information schema queries instead of
  only freeing memory at query end.

Other things
- Removed some not needed set_notnull() calls for not null columns.

include/my_alloc.h

@@ -43,6 +43,7 @@ typedef struct st_mem_root
   /* if block have less memory it will be put in 'used' list */
   size_t min_malloc;
   size_t block_size;               /* initial block size */
+  size_t total_alloc;
   unsigned int block_num;          /* allocated blocks counter */
   /* 
      first free block in queue test counter (if it exceed 

include/mysql.h.pp

@@ -236,6 +236,7 @@ typedef struct st_mem_root
   USED_MEM *pre_alloc;
   size_t min_malloc;
   size_t block_size;
+  size_t total_alloc;
   unsigned int block_num;
   unsigned int first_block_usage;
   void (*error_handler)(void);

mysql-test/r/create.result

@@ -1173,6 +1173,7 @@ t1	CREATE TABLE `t1` (
   `MAX_STAGE` tinyint(2) NOT NULL DEFAULT 0,
   `PROGRESS` decimal(7,3) NOT NULL DEFAULT 0.000,
   `MEMORY_USED` bigint(7) NOT NULL DEFAULT 0,
+  `MAX_MEMORY_USED` bigint(7) NOT NULL DEFAULT 0,
   `EXAMINED_ROWS` int(7) NOT NULL DEFAULT 0,
   `QUERY_ID` bigint(4) NOT NULL DEFAULT 0,
   `INFO_BINARY` blob DEFAULT NULL,
@@ -1196,6 +1197,7 @@ t1	CREATE TEMPORARY TABLE `t1` (
   `MAX_STAGE` tinyint(2) NOT NULL DEFAULT 0,
   `PROGRESS` decimal(7,3) NOT NULL DEFAULT 0.000,
   `MEMORY_USED` bigint(7) NOT NULL DEFAULT 0,
+  `MAX_MEMORY_USED` bigint(7) NOT NULL DEFAULT 0,
   `EXAMINED_ROWS` int(7) NOT NULL DEFAULT 0,
   `QUERY_ID` bigint(4) NOT NULL DEFAULT 0,
   `INFO_BINARY` blob DEFAULT NULL,

mysql-test/suite/funcs_1/datadict/processlist_priv.inc

@@ -158,7 +158,7 @@ WHERE DB = 'information_schema' AND COMMAND = 'Sleep' AND USER = 'ddicttestuser1
 eval SHOW CREATE TABLE $table;
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 eval SHOW $table;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 eval SELECT * FROM $table $select_where ORDER BY id;
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
 eval SELECT $columns FROM $table $select_where ORDER BY id;
@@ -178,7 +178,7 @@ connection con100;
 eval SHOW CREATE TABLE $table;
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 eval SHOW $table;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 eval SELECT * FROM $table $select_where ORDER BY id;
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
 eval SELECT $columns FROM $table $select_where ORDER BY id;
@@ -204,7 +204,7 @@ connection con100;
 SHOW GRANTS;
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 
@@ -216,7 +216,7 @@ connect (con101,localhost,ddicttestuser1,ddictpass,information_schema);
 SHOW GRANTS;
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 
@@ -239,7 +239,7 @@ connect (anonymous1,localhost,"''",,information_schema);
 SHOW GRANTS;
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 
@@ -261,7 +261,7 @@ connect (con102,localhost,ddicttestuser1,ddictpass,information_schema);
 SHOW GRANTS;
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 
@@ -287,7 +287,7 @@ if ($fixed_bug_30395)
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
 }
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 
@@ -308,7 +308,7 @@ connect (con103,localhost,ddicttestuser1,ddictpass,information_schema);
 SHOW GRANTS FOR 'ddicttestuser1'@'localhost';
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 
@@ -330,7 +330,7 @@ connect (con104,localhost,ddicttestuser1,ddictpass,information_schema);
 SHOW GRANTS FOR 'ddicttestuser1'@'localhost';
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 
@@ -377,7 +377,7 @@ connect (con200,localhost,ddicttestuser2,ddictpass,information_schema);
 SHOW GRANTS FOR 'ddicttestuser2'@'localhost';
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 
@@ -398,7 +398,7 @@ connect (con201,localhost,ddicttestuser2,ddictpass,information_schema);
 SHOW GRANTS;
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 
@@ -421,7 +421,7 @@ SHOW GRANTS FOR 'ddicttestuser1'@'localhost';
 GRANT PROCESS ON *.* TO 'ddicttestuser2'@'localhost';
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 
@@ -445,7 +445,7 @@ connect (con108,localhost,ddicttestuser1,ddictpass,information_schema);
 SHOW GRANTS FOR 'ddicttestuser1'@'localhost';
 --replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS
 SHOW processlist;
---replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 ROWS 15 QUERY_ID 17 TID
+--replace_column 1 ID 3 HOST_NAME 6 TIME 9 TIME_MS 13 MEMORY 14 MAX_MEMORY 15 ROWS 16 QUERY_ID 18 TID
 SELECT * FROM information_schema.processlist;
 --real_sleep 0.3
 

mysql-test/suite/funcs_1/datadict/processlist_val.inc

@@ -92,7 +92,7 @@ echo
 #   - INFO must contain the corresponding SHOW/SELECT PROCESSLIST
 #
 # 1. Just dump what we get
---replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <ROWS> 15 <QUERY_ID> 17 <TID>
+--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <MAX_MEMORY> 15 <ROWS> 16 <QUERY_ID> 18 <TID>
 SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 --replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <ROWS>
 SHOW FULL PROCESSLIST;
@@ -159,7 +159,7 @@ let $wait_condition= SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST
                      WHERE COMMAND = 'Sleep' AND USER = 'test_user';
 --source include/wait_condition.inc
 # 1. Just dump what we get
---replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 7 <STATE> 9 <TIME_MS> 13 <MEMORY> 14 <ROWS> 15 <QUERY_ID> 17 <TID>
+--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 7 <STATE> 9 <TIME_MS> 13 <MEMORY> 14 <MAX_MEMORY> 15 <ROWS> 16 <QUERY_ID> 18 <TID>
 SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 --replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
 SHOW FULL PROCESSLIST;
@@ -201,7 +201,7 @@ echo
 #----------------------------------------------------------------------------
 ;
 connection con1;
---replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <ROWS> 15 <QUERY_ID> 17 <TID>
+--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <MAX_MEMORY> 15 <ROWS> 16 <QUERY_ID> 18 <TID>
 SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 --replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
 SHOW FULL PROCESSLIST;
@@ -226,7 +226,7 @@ let $wait_condition= SELECT COUNT(*) = 2 FROM INFORMATION_SCHEMA.PROCESSLIST
 --source include/wait_condition.inc
 connection con2;
 # Just dump what we get
---replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <ROWS> 15 <QUERY_ID> 17 <TID>
+--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <MAX_MEMORY> 15 <ROWS> 16 <QUERY_ID> 18 <TID>
 SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 --replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
 SHOW FULL PROCESSLIST;
@@ -277,7 +277,7 @@ WHERE ID = @test_user_con2_id AND Command IN('Query','Execute')
   AND State = 'User sleep' AND INFO IS NOT NULL ;
 --source include/wait_condition.inc
 # 1. Just dump what we get
---replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <ROWS> 15 <QUERY_ID> 17 <TID>
+--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <MAX_MEMORY> 15 <ROWS> 16 <QUERY_ID> 18 <TID>
 SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 --replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME>
 SHOW FULL PROCESSLIST;
@@ -336,7 +336,7 @@ let $wait_condition= SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST
 #
 # Expect to see the state 'Waiting for table metadata lock' for the third
 # connection because the SELECT collides with the WRITE TABLE LOCK.
---replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <ROWS> 15 <QUERY_ID> 17 <TID>
+--replace_column 1 <ID> 3 <HOST_NAME> 6 <TIME> 9 <TIME_MS> 13 <MEMORY> 14 <MAX_MEMORY> 15 <ROWS> 16 <QUERY_ID> 18 <TID>
 SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 UNLOCK TABLES;
 #
@@ -383,7 +383,7 @@ echo
 # SHOW FULL PROCESSLIST                          Complete statement
 # SHOW PROCESSLIST                               statement truncated after 100 char
 ;
---replace_column 1 <ID> 3 <HOST_NAME> 5 <COMMAND> 6 <TIME> 7 <STATE> 9 <TIME_MS> 13 <MEMORY> 14 <ROWS> 15 <QUERY_ID> 17 <TID>
+--replace_column 1 <ID> 3 <HOST_NAME> 5 <COMMAND> 6 <TIME> 7 <STATE> 9 <TIME_MS> 13 <MEMORY> 14 <MAX_MEMORY> 15 <ROWS> 16 <QUERY_ID> 18 <TID>
 SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST;
 --replace_column 1 <ID> 3 <HOST_NAME> 5 <COMMAND> 6 <TIME> 7 <STATE>
 SHOW FULL PROCESSLIST;

mysql-test/suite/funcs_1/r/is_columns_is.result

@@ -256,18 +256,19 @@ def	information_schema	PLUGINS	PLUGIN_TYPE_VERSION	5	''	NO	varchar	20	60	NULL	NU
 def	information_schema	PLUGINS	PLUGIN_VERSION	2	''	NO	varchar	20	60	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(20)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	COMMAND	5	''	NO	varchar	16	48	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(16)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	DB	4	NULL	YES	varchar	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(64)			select		NEVER	NULL
-def	information_schema	PROCESSLIST	EXAMINED_ROWS	14	0	NO	int	NULL	NULL	10	0	NULL	NULL	NULL	int(7)			select		NEVER	NULL
+def	information_schema	PROCESSLIST	EXAMINED_ROWS	15	0	NO	int	NULL	NULL	10	0	NULL	NULL	NULL	int(7)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	HOST	3	''	NO	varchar	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(64)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	ID	1	0	NO	bigint	NULL	NULL	19	0	NULL	NULL	NULL	bigint(4)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	INFO	8	NULL	YES	longtext	4294967295	4294967295	NULL	NULL	NULL	utf8	utf8_general_ci	longtext			select		NEVER	NULL
-def	information_schema	PROCESSLIST	INFO_BINARY	16	NULL	YES	blob	65535	65535	NULL	NULL	NULL	NULL	NULL	blob			select		NEVER	NULL
+def	information_schema	PROCESSLIST	INFO_BINARY	17	NULL	YES	blob	65535	65535	NULL	NULL	NULL	NULL	NULL	blob			select		NEVER	NULL
+def	information_schema	PROCESSLIST	MAX_MEMORY_USED	14	0	NO	bigint	NULL	NULL	19	0	NULL	NULL	NULL	bigint(7)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	MAX_STAGE	11	0	NO	tinyint	NULL	NULL	3	0	NULL	NULL	NULL	tinyint(2)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	MEMORY_USED	13	0	NO	bigint	NULL	NULL	19	0	NULL	NULL	NULL	bigint(7)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	PROGRESS	12	0.000	NO	decimal	NULL	NULL	7	3	NULL	NULL	NULL	decimal(7,3)			select		NEVER	NULL
-def	information_schema	PROCESSLIST	QUERY_ID	15	0	NO	bigint	NULL	NULL	19	0	NULL	NULL	NULL	bigint(4)			select		NEVER	NULL
+def	information_schema	PROCESSLIST	QUERY_ID	16	0	NO	bigint	NULL	NULL	19	0	NULL	NULL	NULL	bigint(4)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	STAGE	10	0	NO	tinyint	NULL	NULL	3	0	NULL	NULL	NULL	tinyint(2)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	STATE	7	NULL	YES	varchar	64	192	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(64)			select		NEVER	NULL
-def	information_schema	PROCESSLIST	TID	17	0	NO	bigint	NULL	NULL	19	0	NULL	NULL	NULL	bigint(4)			select		NEVER	NULL
+def	information_schema	PROCESSLIST	TID	18	0	NO	bigint	NULL	NULL	19	0	NULL	NULL	NULL	bigint(4)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	TIME	6	0	NO	int	NULL	NULL	10	0	NULL	NULL	NULL	int(7)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	TIME_MS	9	0.000	NO	decimal	NULL	NULL	22	3	NULL	NULL	NULL	decimal(22,3)			select		NEVER	NULL
 def	information_schema	PROCESSLIST	USER	2	''	NO	varchar	128	384	NULL	NULL	NULL	utf8	utf8_general_ci	varchar(128)			select		NEVER	NULL
@@ -797,6 +798,7 @@ NULL	information_schema	PROCESSLIST	STAGE	tinyint	NULL	NULL	NULL	NULL	tinyint(2)
 NULL	information_schema	PROCESSLIST	MAX_STAGE	tinyint	NULL	NULL	NULL	NULL	tinyint(2)
 NULL	information_schema	PROCESSLIST	PROGRESS	decimal	NULL	NULL	NULL	NULL	decimal(7,3)
 NULL	information_schema	PROCESSLIST	MEMORY_USED	bigint	NULL	NULL	NULL	NULL	bigint(7)
+NULL	information_schema	PROCESSLIST	MAX_MEMORY_USED	bigint	NULL	NULL	NULL	NULL	bigint(7)
 NULL	information_schema	PROCESSLIST	EXAMINED_ROWS	int	NULL	NULL	NULL	NULL	int(7)
 NULL	information_schema	PROCESSLIST	QUERY_ID	bigint	NULL	NULL	NULL	NULL	bigint(4)
 1.0000	information_schema	PROCESSLIST	INFO_BINARY	blob	65535	65535	NULL	NULL	blob

mysys/my_alloc.c

@@ -68,6 +68,7 @@ void init_alloc_root(MEM_ROOT *mem_root, size_t block_size,
   mem_root->error_handler= 0;
   mem_root->block_num= 4;			/* We shift this with >>2 */
   mem_root->first_block_usage= 0;
+  mem_root->total_alloc= 0;
 
 #if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG))
   if (pre_alloc_size)
@@ -77,6 +78,7 @@ void init_alloc_root(MEM_ROOT *mem_root, size_t block_size,
 			       MYF(my_flags))))
     {
       mem_root->free->size= pre_alloc_size+ALIGN_SIZE(sizeof(USED_MEM));
+      mem_root->total_alloc= pre_alloc_size+ALIGN_SIZE(sizeof(USED_MEM));
       mem_root->free->left= pre_alloc_size;
       mem_root->free->next= 0;
     }
@@ -134,6 +136,7 @@ void reset_root_defaults(MEM_ROOT *mem_root, size_t block_size,
         {
           /* remove block from the list and free it */
           *prev= mem->next;
+          mem_root->total_alloc-= mem->size;
           my_free(mem);
         }
         else
@@ -145,9 +148,10 @@ void reset_root_defaults(MEM_ROOT *mem_root, size_t block_size,
                                                        block_size)))))
       {
         mem->size= size; 
+        mem_root->total_alloc+= size;
         mem->left= pre_alloc_size;
         mem->next= *prev;
-        *prev= mem_root->pre_alloc= mem; 
+        *prev= mem_root->pre_alloc= mem;
       }
       else
       {
@@ -190,8 +194,10 @@ void *alloc_root(MEM_ROOT *mem_root, size_t length)
     DBUG_RETURN((uchar*) 0);			/* purecov: inspected */
   }
   next->next= mem_root->used;
+  next->left= 0;
   next->size= length;
   mem_root->used= next;
+  mem_root->total_alloc+= length;
   DBUG_PRINT("exit",("ptr: %p", (((char*) next)+
                                  ALIGN_SIZE(sizeof(USED_MEM)))));
   DBUG_RETURN((uchar*) (((char*) next)+ALIGN_SIZE(sizeof(USED_MEM))));
@@ -244,6 +250,7 @@ void *alloc_root(MEM_ROOT *mem_root, size_t length)
       DBUG_RETURN((void*) 0);                      /* purecov: inspected */
     }
     mem_root->block_num++;
+    mem_root->total_alloc+= get_size;
     next->next= *prev;
     next->size= get_size;
     next->left= get_size-ALIGN_SIZE(sizeof(USED_MEM));
@@ -346,6 +353,7 @@ static inline void mark_blocks_free(MEM_ROOT* root)
   /* Now everything is set; Indicate that nothing is used anymore */
   root->used= 0;
   root->first_block_usage= 0;
+  root->block_num= 4;
 }
 
 
@@ -374,11 +382,17 @@ void free_root(MEM_ROOT *root, myf MyFlags)
   DBUG_ENTER("free_root");
   DBUG_PRINT("enter",("root: %p  flags: %u", root, (uint) MyFlags));
 
+#if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG))
+  /*
+    There is no point in using mark_blocks_free when using valgrind as
+    it will not reclaim any memory
+  */
   if (MyFlags & MY_MARK_BLOCKS_FREE)
   {
     mark_blocks_free(root);
     DBUG_VOID_RETURN;
   }
+#endif
   if (!(MyFlags & MY_KEEP_PREALLOC))
     root->pre_alloc=0;
 
@@ -386,13 +400,19 @@ void free_root(MEM_ROOT *root, myf MyFlags)
   {
     old=next; next= next->next ;
     if (old != root->pre_alloc)
+    {
+      root->total_alloc-= old->size;
       my_free(old);
+    }
   }
   for (next=root->free ; next ;)
   {
     old=next; next= next->next;
     if (old != root->pre_alloc)
+    {
+      root->total_alloc-= old->size;
       my_free(old);
+    }
   }
   root->used=root->free=0;
   if (root->pre_alloc)

sql/mysqld.cc

@@ -381,6 +381,7 @@ mysql_cond_t COND_thread_cache;
 static mysql_cond_t COND_flush_thread_cache;
 mysql_cond_t COND_slave_background;
 static DYNAMIC_ARRAY all_options;
+static longlong start_memory_used;
 
 /* Global variables */
 
@@ -4040,6 +4041,8 @@ static void my_malloc_size_cb_func(long long size, my_bool is_thread_specific)
                         (longlong) thd->status_var.local_memory_used,
                         size));
     thd->status_var.local_memory_used+= size;
+    set_if_bigger(thd->status_var.max_local_memory_used,
+                  thd->status_var.local_memory_used);
     if (size > 0 &&
         thd->status_var.local_memory_used > (int64)thd->variables.max_mem_used &&
         !thd->killed && !thd->get_stmt_da()->is_set())
@@ -6065,6 +6068,9 @@ int mysqld_main(int argc, char **argv)
 
   MYSQL_SET_STAGE(0 ,__FILE__, __LINE__);
 
+  /* Memory used when everything is setup */
+  start_memory_used= global_status_var.global_memory_used;
+
 #if defined(_WIN32) || defined(HAVE_SMEM)
   handle_connections_methods();
 #else
@@ -8462,6 +8468,7 @@ SHOW_VAR status_vars[]= {
   {"Master_gtid_wait_time",    (char*) offsetof(STATUS_VAR, master_gtid_wait_time), SHOW_LONGLONG_STATUS},
   {"Max_used_connections",     (char*) &max_used_connections,  SHOW_LONG},
   {"Memory_used",              (char*) &show_memory_used, SHOW_SIMPLE_FUNC},
+  {"Memory_used_initial",      (char*) &start_memory_used, SHOW_LONGLONG},
   {"Not_flushed_delayed_rows", (char*) &delayed_rows_in_use,    SHOW_LONG_NOFLUSH},
   {"Open_files",               (char*) &my_file_opened,         SHOW_LONG_NOFLUSH},
   {"Open_streams",             (char*) &my_stream_opened,       SHOW_LONG_NOFLUSH},

sql/sql_class.h

@@ -815,6 +815,7 @@ typedef struct system_status_var
   double cpu_time, busy_time;
   /* Don't initialize */
   /* Memory used for thread local storage */
+  int64 max_local_memory_used;
   volatile int64 local_memory_used;
   /* Memory allocated for global usage */
   volatile int64 global_memory_used;
@@ -4513,7 +4514,6 @@ class THD :public Statement,
     See also sp_head::merge_lex().
   */
   bool restore_from_local_lex_to_old_lex(LEX *oldlex);
-
 };
 
 inline void add_to_active_threads(THD *thd)

sql/sql_const.h

@@ -175,6 +175,11 @@
 #define TABLE_ALLOC_BLOCK_SIZE		1024
 #define WARN_ALLOC_BLOCK_SIZE		2048
 #define WARN_ALLOC_PREALLOC_SIZE	1024
+/*
+  Note that if we are using 32K or less, then TCmalloc will use a local
+  heap without locks!
+*/
+#define SHOW_ALLOC_BLOCK_SIZE           (32768-MALLOC_OVERHEAD)
 
 /*
   The following parameters is to decide when to use an extra cache to

sql/sql_show.cc

@@ -93,7 +93,6 @@ enum enum_i_s_events_fields
 
 #define USERNAME_WITH_HOST_CHAR_LENGTH (USERNAME_CHAR_LENGTH + HOSTNAME_LENGTH + 2)
 
-
 static const LEX_CSTRING trg_action_time_type_names[]=
 {
   { STRING_WITH_LEN("BEFORE") },
@@ -3092,17 +3091,17 @@ int fill_schema_processlist(THD* thd, TABLE_LIST* tables, COND* cond)
       {
         table->field[7]->store(tmp->query(),
                                MY_MIN(PROCESS_LIST_INFO_WIDTH,
-                                   tmp->query_length()), cs);
+                                      tmp->query_length()), cs);
         table->field[7]->set_notnull();
       }
 
       /* INFO_BINARY */
       if (tmp->query())
       {
-        table->field[15]->store(tmp->query(),
+        table->field[16]->store(tmp->query(),
                                 MY_MIN(PROCESS_LIST_INFO_WIDTH,
                                 tmp->query_length()), &my_charset_bin);
-        table->field[15]->set_notnull();
+        table->field[16]->set_notnull();
       }
 
       /*
@@ -3125,14 +3124,14 @@ int fill_schema_processlist(THD* thd, TABLE_LIST* tables, COND* cond)
       */
       table->field[12]->store((longlong) tmp->status_var.local_memory_used,
                               FALSE);
-      table->field[12]->set_notnull();
-      table->field[13]->store((longlong) tmp->get_examined_row_count(), TRUE);
-      table->field[13]->set_notnull();
+      table->field[13]->store((longlong) tmp->status_var.max_local_memory_used,
+                              FALSE);
+      table->field[14]->store((longlong) tmp->get_examined_row_count(), TRUE);
 
       /* QUERY_ID */
-      table->field[14]->store(tmp->query_id, TRUE);
+      table->field[15]->store(tmp->query_id, TRUE);
 
-      table->field[16]->store(tmp->os_thread_id);
+      table->field[17]->store(tmp->os_thread_id);
 
       if (schema_table_store_record(thd, table))
       {
@@ -4293,14 +4292,15 @@ static void get_table_engine_for_i_s(THD *thd, char *buf, TABLE_LIST *tl,
   @retval TRUE  - Failure.
 */
 static bool
-fill_schema_table_by_open(THD *thd, bool is_show_fields_or_keys,
+fill_schema_table_by_open(THD *thd, MEM_ROOT *mem_root,
+                          bool is_show_fields_or_keys,
                           TABLE *table, ST_SCHEMA_TABLE *schema_table,
                           LEX_CSTRING *orig_db_name,
                           LEX_CSTRING *orig_table_name,
                           Open_tables_backup *open_tables_state_backup,
                           bool can_deadlock)
 {
-  Query_arena i_s_arena(thd->mem_root,
+  Query_arena i_s_arena(mem_root,
                         Query_arena::STMT_CONVENTIONAL_EXECUTION),
               backup_arena, *old_arena;
   LEX *old_lex= thd->lex, temp_lex, *lex;
@@ -4877,8 +4877,11 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
 #endif
   uint table_open_method= tables->table_open_method;
   bool can_deadlock;
+  MEM_ROOT tmp_mem_root;
   DBUG_ENTER("get_all_tables");
 
+  bzero(&tmp_mem_root, sizeof(tmp_mem_root));
+
   /*
     In cases when SELECT from I_S table being filled by this call is
     part of statement which also uses other tables or is being executed
@@ -4914,7 +4917,7 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
     table_name.str= lsel->table_list.first->table_name;
     table_name.length= lsel->table_list.first->table_name_length;
 
-    error= fill_schema_table_by_open(thd, TRUE,
+    error= fill_schema_table_by_open(thd, thd->mem_root, TRUE,
                                      table, schema_table,
                                      &db_name, &table_name,
                                      &open_tables_state_backup,
@@ -4939,6 +4942,11 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
 
   if (make_db_list(thd, &db_names, &plan->lookup_field_vals))
     goto err;
+
+  /* Use tmp_mem_root to allocate data for opened tables */
+  init_alloc_root(&tmp_mem_root, SHOW_ALLOC_BLOCK_SIZE, SHOW_ALLOC_BLOCK_SIZE,
+                  MY_THREAD_SPECIFIC);
+
   for (size_t i=0; i < db_names.elements(); i++)
   {
     LEX_CSTRING *db_name= db_names.at(i);
@@ -5024,12 +5032,13 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
             }
 
             DEBUG_SYNC(thd, "before_open_in_get_all_tables");
-            if (fill_schema_table_by_open(thd, FALSE,
+            if (fill_schema_table_by_open(thd, &tmp_mem_root, FALSE,
                                           table, schema_table,
                                           db_name, table_name,
                                           &open_tables_state_backup,
                                           can_deadlock))
               goto err;
+            free_root(&tmp_mem_root, MY_MARK_BLOCKS_FREE);
           }
         }
       }
@@ -5039,6 +5048,7 @@ int get_all_tables(THD *thd, TABLE_LIST *tables, COND *cond)
   error= 0;
 err:
   thd->restore_backup_open_tables_state(&open_tables_state_backup);
+  free_root(&tmp_mem_root, 0);
 
   DBUG_RETURN(error);
 }
@@ -9064,6 +9074,7 @@ ST_FIELD_INFO processlist_fields_info[]=
   {"PROGRESS", 703, MYSQL_TYPE_DECIMAL,  0, 0, "Progress",
    SKIP_OPEN_TABLE},
   {"MEMORY_USED", 7, MYSQL_TYPE_LONGLONG, 0, 0, "Memory_used", SKIP_OPEN_TABLE},
+  {"MAX_MEMORY_USED", 7, MYSQL_TYPE_LONGLONG, 0, 0, "Max_memory_used", SKIP_OPEN_TABLE},
   {"EXAMINED_ROWS", 7, MYSQL_TYPE_LONG, 0, 0, "Examined_rows", SKIP_OPEN_TABLE},
   {"QUERY_ID", 4, MYSQL_TYPE_LONGLONG, 0, 0, 0, SKIP_OPEN_TABLE},
   {"INFO_BINARY", PROCESS_LIST_INFO_WIDTH, MYSQL_TYPE_BLOB, 0, 1,