#At file:///home/satya/WORK/37408/mysql-5.0-bugteam-37408/ based on revid:joro@stripped
2849 Satya B 2009-11-25
Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
When compressed myisam files are opened, they are always memory mapped
sometimes causing memory swapping problems.
When we mmap the myisam compressed tables of size greater than the memory
available, the kswapd0 process utilization is very high consuming 30-40% of
the cpu. This happens only with linux kernels older than 2.6.9
With newer linux kernels, we don't have this problem of high cpu consumption
and this option may not be required.
The option 'myisam_mmap_size' is added to limit the amount of memory used for
memory mapping of myisam files. This option is not dynamic.
The default value on 32 bit system is 4294967295 bytes and on 64 bit system it
is 18446744073709547520 bytes.
Note: Testcase only tests the option variable. The actual bug has be to
tested manually.
@ include/my_global.h
Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
define SIZE_T_MAX
@ include/myisam.h
Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
declare 'myisam_mmap_size' and 'myisam_mmap_used' variables and the mutex
THR_LOCK_myisam_mmap
@ myisam/mi_packrec.c
Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
add 'myisam_mmap_size' option which limits the memory available to mmap of
myisam files
@ myisam/mi_static.c
Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
declare 'myisam_mmap_size' and 'myisam_mmap_used' variables and the mutex
THR_LOCK_myisam_mmap
@ mysql-test/r/variables.result
Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
Testcase for BUG#37408 to test the myisam_mmap_size option
@ mysql-test/t/variables.test
Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
Testcase for BUG#37408 to test the myisam_mmap_size option
@ sql/mysqld.cc
Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
add the 'myisam_mmap_size' option
@ sql/set_var.cc
Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
add the 'myisam_mmap_size' to the SHOW VARIABLES list
@ sql/set_var.h
Fix for Bug #37408 - Compressed MyISAM files should not require/use mmap()
Add system variable type 'sys_var_ulonglong_const_ptr'
modified:
include/my_global.h
include/myisam.h
myisam/mi_packrec.c
myisam/mi_static.c
mysql-test/r/variables.result
mysql-test/t/variables.test
sql/mysqld.cc
sql/set_var.cc
sql/set_var.h
=== modified file 'include/my_global.h'
--- a/include/my_global.h 2009-09-17 15:10:30 +0000
+++ b/include/my_global.h 2009-11-25 12:46:32 +0000
@@ -793,6 +793,9 @@ typedef SOCKET_SIZE_TYPE size_socket;
#define DBL_MAX 1.79769313486231470e+308
#define FLT_MAX ((float)3.40282346638528860e+38)
#endif
+#ifndef SIZE_T_MAX
+#define SIZE_T_MAX (~((size_t) 0))
+#endif
#ifndef HAVE_FINITE
#define finite(x) (1.0 / fabs(x) > 0.0)
=== modified file 'include/myisam.h'
--- a/include/myisam.h 2009-10-27 13:11:06 +0000
+++ b/include/myisam.h 2009-11-25 12:46:32 +0000
@@ -270,6 +270,8 @@ extern ulong myisam_bulk_insert_tree_siz
/* usually used to check if a symlink points into the mysql data home */
/* which is normally forbidden */
extern int (*myisam_test_invalid_symlink)(const char *filename);
+extern ulonglong myisam_mmap_size, myisam_mmap_used;
+extern pthread_mutex_t THR_LOCK_myisam_mmap;
/* Prototypes for myisam-functions */
=== modified file 'myisam/mi_packrec.c'
--- a/myisam/mi_packrec.c 2009-08-28 15:51:31 +0000
+++ b/myisam/mi_packrec.c 2009-11-25 12:46:32 +0000
@@ -1504,7 +1504,8 @@ my_bool _mi_memmap_file(MI_INFO *info)
if (!share->file_map)
{
my_off_t data_file_length= share->state.state.data_file_length;
- if (data_file_length > (my_off_t) (~((size_t) 0)) - MEMMAP_EXTRA_MARGIN)
+ if ((data_file_length + myisam_mmap_used + MEMMAP_EXTRA_MARGIN) >
+ myisam_mmap_size)
{
DBUG_PRINT("warning", ("File is too large for mmap"));
DBUG_RETURN(0);
@@ -1525,6 +1526,10 @@ my_bool _mi_memmap_file(MI_INFO *info)
DBUG_RETURN(0);
}
share->file_map= file_map;
+
+ pthread_mutex_lock(&THR_LOCK_myisam_mmap);
+ myisam_mmap_used+= (data_file_length + MEMMAP_EXTRA_MARGIN);
+ pthread_mutex_unlock(&THR_LOCK_myisam_mmap);
}
info->opt_flag|= MEMMAP_USED;
info->read_record=share->read_record=_mi_read_mempack_record;
@@ -1538,6 +1543,11 @@ void _mi_unmap_file(MI_INFO *info)
VOID(my_munmap(info->s->file_map,
(size_t) info->s->state.state.data_file_length+
MEMMAP_EXTRA_MARGIN));
+
+ pthread_mutex_lock(&THR_LOCK_myisam_mmap);
+ myisam_mmap_used-= info->s->state.state.data_file_length +
+ MEMMAP_EXTRA_MARGIN;
+ pthread_mutex_unlock(&THR_LOCK_myisam_mmap);
}
=== modified file 'myisam/mi_static.c'
--- a/myisam/mi_static.c 2009-10-27 13:11:06 +0000
+++ b/myisam/mi_static.c 2009-11-25 12:46:32 +0000
@@ -40,6 +40,8 @@ ulong myisam_concurrent_insert= 0;
my_off_t myisam_max_temp_length= MAX_FILE_SIZE;
ulong myisam_bulk_insert_tree_size=8192*1024;
ulong myisam_data_pointer_size=4;
+ulonglong myisam_mmap_size= SIZE_T_MAX, myisam_mmap_used= 0;
+pthread_mutex_t THR_LOCK_myisam_mmap;
static int always_valid(const char *filename __attribute__((unused)))
=== modified file 'mysql-test/r/variables.result'
--- a/mysql-test/r/variables.result 2009-06-19 09:27:19 +0000
+++ b/mysql-test/r/variables.result 2009-11-25 12:46:32 +0000
@@ -904,3 +904,9 @@ set global server_id =@m
set global slow_launch_time =@my_slow_launch_time;
set global storage_engine =@my_storage_engine;
set global thread_cache_size =@my_thread_cache_size;
+#
+# BUG#37408 - Compressed MyISAM files should not require/use mmap()
+#
+# Test 'myisam_mmap_size' option is not dynamic
+SET @@myisam_mmap_size= 500M;
+ERROR HY000: Variable 'myisam_mmap_size' is a read only variable
=== modified file 'mysql-test/t/variables.test'
--- a/mysql-test/t/variables.test 2009-06-19 09:27:19 +0000
+++ b/mysql-test/t/variables.test 2009-11-25 12:46:32 +0000
@@ -765,3 +765,9 @@ set global slow_launch_time =@m
set global storage_engine =@my_storage_engine;
set global thread_cache_size =@my_thread_cache_size;
+--echo #
+--echo # BUG#37408 - Compressed MyISAM files should not require/use mmap()
+--echo #
+--echo # Test 'myisam_mmap_size' option is not dynamic
+--error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SET @@myisam_mmap_size= 500M;
=== modified file 'sql/mysqld.cc'
--- a/sql/mysqld.cc 2009-10-27 13:11:06 +0000
+++ b/sql/mysqld.cc 2009-11-25 12:46:32 +0000
@@ -4975,7 +4975,8 @@ enum options_mysqld
OPT_MAX_WRITE_LOCK_COUNT, OPT_BULK_INSERT_BUFFER_SIZE,
OPT_MAX_ERROR_COUNT, OPT_MULTI_RANGE_COUNT, OPT_MYISAM_DATA_POINTER_SIZE,
OPT_MYISAM_BLOCK_SIZE, OPT_MYISAM_MAX_EXTRA_SORT_FILE_SIZE,
- OPT_MYISAM_MAX_SORT_FILE_SIZE, OPT_MYISAM_SORT_BUFFER_SIZE,
+ OPT_MYISAM_MAX_SORT_FILE_SIZE, OPT_MYISAM_MMAP_SIZE,
+ OPT_MYISAM_SORT_BUFFER_SIZE,
OPT_MYISAM_STATS_METHOD,
OPT_NET_BUFFER_LENGTH, OPT_NET_RETRY_COUNT,
OPT_NET_READ_TIMEOUT, OPT_NET_WRITE_TIMEOUT,
@@ -6254,6 +6255,10 @@ The minimum value for this variable is 4
(gptr*) &max_system_variables.myisam_max_sort_file_size, 0,
GET_ULL, REQUIRED_ARG, (longlong) LONG_MAX, 0, (ulonglong) MAX_FILE_SIZE,
0, 1024*1024, 0},
+ {"myisam_mmap_size", OPT_MYISAM_MMAP_SIZE,
+ "Can be used to restrict the total memory used for memory mmaping of myisam files",
+ (gptr*) &myisam_mmap_size, (gptr*) &myisam_mmap_size, 0,
+ GET_ULL, REQUIRED_ARG, SIZE_T_MAX, 0, SIZE_T_MAX, 0, 1, 0},
{"myisam_repair_threads", OPT_MYISAM_REPAIR_THREADS,
"Number of threads to use when repairing MyISAM tables. The value of 1 disables parallel repair.",
(gptr*) &global_system_variables.myisam_repair_threads,
=== modified file 'sql/set_var.cc'
--- a/sql/set_var.cc 2009-07-16 12:37:38 +0000
+++ b/sql/set_var.cc 2009-11-25 12:46:32 +0000
@@ -290,6 +290,9 @@ sys_var_long_ptr sys_myisam_data_pointer
sys_var_thd_ulonglong sys_myisam_max_sort_file_size("myisam_max_sort_file_size", &SV::myisam_max_sort_file_size, fix_myisam_max_sort_file_size, 1);
sys_var_thd_ulong sys_myisam_repair_threads("myisam_repair_threads", &SV::myisam_repair_threads);
sys_var_thd_ulong sys_myisam_sort_buffer_size("myisam_sort_buffer_size", &SV::myisam_sort_buff_size);
+sys_var_ulonglong_const_ptr sys_myisam_mmap_size("myisam_mmap_size",
+ &myisam_mmap_size);
+
sys_var_thd_enum sys_myisam_stats_method("myisam_stats_method",
&SV::myisam_stats_method,
@@ -723,6 +726,7 @@ sys_var *sys_variables[]=
&sys_multi_range_count,
&sys_myisam_data_pointer_size,
&sys_myisam_max_sort_file_size,
+ &sys_myisam_mmap_size,
&sys_myisam_repair_threads,
&sys_myisam_sort_buffer_size,
&sys_myisam_stats_method,
@@ -1026,6 +1030,7 @@ struct show_var_st init_vars[]= {
{sys_myisam_data_pointer_size.name, (char*) &sys_myisam_data_pointer_size, SHOW_SYS},
{sys_myisam_max_sort_file_size.name, (char*) &sys_myisam_max_sort_file_size,
SHOW_SYS},
+ {sys_myisam_mmap_size.name, (char*) &sys_myisam_mmap_size, SHOW_SYS},
{"myisam_recover_options", (char*) &myisam_recover_options_str, SHOW_CHAR_PTR},
{sys_myisam_repair_threads.name, (char*) &sys_myisam_repair_threads,
SHOW_SYS},
=== modified file 'sql/set_var.h'
--- a/sql/set_var.h 2009-06-19 09:27:19 +0000
+++ b/sql/set_var.h 2009-11-25 12:46:32 +0000
@@ -148,6 +148,22 @@ public:
{ return (byte*) value; }
};
+class sys_var_ulonglong_const_ptr :public sys_var
+{
+public:
+ ulonglong *value;
+ sys_var_ulonglong_const_ptr(const char *name_arg, ulonglong *value_ptr_arg)
+ :sys_var(name_arg),value(value_ptr_arg) {}
+ sys_var_ulonglong_const_ptr(const char *name_arg, ulonglong *value_ptr_arg,
+ sys_after_update_func func)
+ :sys_var(name_arg,func), value(value_ptr_arg) {}
+ bool update(THD *thd, set_var *var) { return 1; }
+ void set_default(THD *thd, enum_var_type type) {};
+ SHOW_TYPE show_type() { return SHOW_LONGLONG; }
+ byte *value_ptr(THD *thd, enum_var_type type, LEX_STRING *base)
+ { return (byte*) value; }
+ bool is_readonly() const { return 1; }
+};
class sys_var_bool_ptr :public sys_var
{
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