increase upper value of max_prepared_stmt_count to UINT32_MAX

The upper 1M limit for max_prepared_stmt_count was set over 10 years
ago. It doesn't suite current hardware and a sysbench oltp_read_write
test with 512 threads will hit this limit.

mysql-test/r/perror.result

@@ -3,4 +3,4 @@ MySQL error code 1062 (ER_DUP_ENTRY): Duplicate entry '%-.192s' for key %d
 MySQL error code 1408 (ER_STARTUP): %s: ready for connections.
 Version: '%s'  socket: '%s'  port: %d  %s
 MySQL error code 1459 (ER_TABLE_NEEDS_UPGRADE): Table upgrade required. Please do "REPAIR TABLE `%-.32s`" or dump/reload to fix it!
-MySQL error code 1461 (ER_MAX_PREPARED_STMT_COUNT_REACHED): Can't create more than max_prepared_stmt_count statements (current value: %lu)
+MySQL error code 1461 (ER_MAX_PREPARED_STMT_COUNT_REACHED): Can't create more than max_prepared_stmt_count statements (current value: %u)

mysql-test/r/ps.result

@@ -820,7 +820,7 @@ Warnings:
 Warning	1292	Truncated incorrect max_prepared_stmt_count value: '10000000000000000'
 select @@max_prepared_stmt_count;
 @@max_prepared_stmt_count
-1048576
+4294967295
 set global max_prepared_stmt_count=default;
 select @@max_prepared_stmt_count;
 @@max_prepared_stmt_count

mysql-test/suite/sys_vars/r/max_prepared_stmt_count_basic.result

@@ -46,40 +46,40 @@ Warnings:
 Warning	1292	Truncated incorrect max_prepared_stmt_count value: '100000000000'
 SELECT @@global.max_prepared_stmt_count;
 @@global.max_prepared_stmt_count
-1048576
+4294967295
 SET @@global.max_prepared_stmt_count = 10000.01;
 ERROR 42000: Incorrect argument type to variable 'max_prepared_stmt_count'
 SELECT @@global.max_prepared_stmt_count;
 @@global.max_prepared_stmt_count
-1048576
+4294967295
 SET @@global.max_prepared_stmt_count = -1024;
 Warnings:
 Warning	1292	Truncated incorrect max_prepared_stmt_count value: '-1024'
 SELECT @@global.max_prepared_stmt_count;
 @@global.max_prepared_stmt_count
 0
-SET @@global.max_prepared_stmt_count = 1048577;
+SET @@global.max_prepared_stmt_count = 4294967296;
 Warnings:
-Warning	1292	Truncated incorrect max_prepared_stmt_count value: '1048577'
+Warning	1292	Truncated incorrect max_prepared_stmt_count value: '4294967296'
 SELECT @@global.max_prepared_stmt_count;
 @@global.max_prepared_stmt_count
-1048576
-SET @@global.max_prepared_stmt_count = 104857612;
+4294967295
+SET @@global.max_prepared_stmt_count = 4294967295*1024;
 Warnings:
-Warning	1292	Truncated incorrect max_prepared_stmt_count value: '104857612'
+Warning	1292	Truncated incorrect max_prepared_stmt_count value: '4398046510080'
 SELECT @@global.max_prepared_stmt_count;
 @@global.max_prepared_stmt_count
-1048576
+4294967295
 SET @@global.max_prepared_stmt_count = ON;
 ERROR 42000: Incorrect argument type to variable 'max_prepared_stmt_count'
 SELECT @@global.max_prepared_stmt_count;
 @@global.max_prepared_stmt_count
-1048576
+4294967295
 SET @@global.max_prepared_stmt_count = 'test';
 ERROR 42000: Incorrect argument type to variable 'max_prepared_stmt_count'
 SELECT @@global.max_prepared_stmt_count;
 @@global.max_prepared_stmt_count
-1048576
+4294967295
 '#-------------------FN_DYNVARS_081_05----------------------------#'
 SET @@session.max_prepared_stmt_count = 4096;
 ERROR HY000: Variable 'max_prepared_stmt_count' is a GLOBAL variable and should be set with SET GLOBAL

mysql-test/suite/sys_vars/t/max_prepared_stmt_count_basic.test

@@ -92,9 +92,9 @@ SET @@global.max_prepared_stmt_count = 10000.01;
 SELECT @@global.max_prepared_stmt_count;
 SET @@global.max_prepared_stmt_count = -1024;
 SELECT @@global.max_prepared_stmt_count;
-SET @@global.max_prepared_stmt_count = 1048577;
+SET @@global.max_prepared_stmt_count = 4294967296;
 SELECT @@global.max_prepared_stmt_count;
-SET @@global.max_prepared_stmt_count = 104857612;
+SET @@global.max_prepared_stmt_count = 4294967295*1024;
 SELECT @@global.max_prepared_stmt_count;
 
 --Error ER_WRONG_TYPE_FOR_VAR

sql/mysqld.cc

@@ -532,7 +532,7 @@ bool max_user_connections_checking=0;
   Limit of the total number of prepared statements in the server.
   Is necessary to protect the server against out-of-memory attacks.
 */
-ulong max_prepared_stmt_count;
+uint max_prepared_stmt_count;
 /**
   Current total number of prepared statements in the server. This number
   is exact, and therefore may not be equal to the difference between
@@ -543,7 +543,7 @@ ulong max_prepared_stmt_count;
   two different connections, this counts as two distinct prepared
   statements.
 */
-ulong prepared_stmt_count=0;
+uint prepared_stmt_count=0;
 ulong thread_id=1L,current_pid;
 ulong slow_launch_threads = 0;
 uint sync_binlog_period= 0, sync_relaylog_period= 0,

sql/mysqld.h

@@ -178,7 +178,7 @@ extern ulong slave_trans_retries;
 extern uint  slave_net_timeout;
 extern int max_user_connections;
 extern ulong what_to_log,flush_time;
-extern ulong max_prepared_stmt_count, prepared_stmt_count;
+extern uint max_prepared_stmt_count, prepared_stmt_count;
 extern ulong open_files_limit;
 extern ulonglong binlog_cache_size, binlog_stmt_cache_size;
 extern ulonglong max_binlog_cache_size, max_binlog_stmt_cache_size;

sql/share/errmsg-utf8.txt

@@ -5577,8 +5577,8 @@ ER_SP_NO_AGGREGATE 42000
         eng "AGGREGATE is not supported for stored functions"
         ger "AGGREGATE wird bei gespeicherten Funktionen nicht unterstützt"
 ER_MAX_PREPARED_STMT_COUNT_REACHED 42000
-        eng "Can't create more than max_prepared_stmt_count statements (current value: %lu)"
-        ger "Kann nicht mehr Anweisungen als max_prepared_stmt_count erzeugen (aktueller Wert: %lu)"
+        eng "Can't create more than max_prepared_stmt_count statements (current value: %u)"
+        ger "Kann nicht mehr Anweisungen als max_prepared_stmt_count erzeugen (aktueller Wert: %u)"
 ER_VIEW_RECURSIVE
         eng "`%-.192s`.`%-.192s` contains view recursion"
         ger "`%-.192s`.`%-.192s` enthält View-Rekursion"

sql/sys_vars.cc

@@ -1932,11 +1932,11 @@ static Sys_var_ulong Sys_max_long_data_size(
        BLOCK_SIZE(1));
 
 static PolyLock_mutex PLock_prepared_stmt_count(&LOCK_prepared_stmt_count);
-static Sys_var_ulong Sys_max_prepared_stmt_count(
+static Sys_var_uint Sys_max_prepared_stmt_count(
        "max_prepared_stmt_count",
        "Maximum number of prepared statements in the server",
        GLOBAL_VAR(max_prepared_stmt_count), CMD_LINE(REQUIRED_ARG),
-       VALID_RANGE(0, 1024*1024), DEFAULT(16382), BLOCK_SIZE(1),
+       VALID_RANGE(0, UINT_MAX32), DEFAULT(16382), BLOCK_SIZE(1),
        &PLock_prepared_stmt_count);
 
 static Sys_var_ulong Sys_max_sort_length(