mysql默认时区:
mysql> show variables like \'%time_zone%\'; +------------------+--------+ | Variable_name | Value | +------------------+--------+ | system_time_zone | PDT | | time_zone | SYSTEM | +------------------+--------+ 2 rows in set (0.01 sec)
my.cnf配制文件修改： 可以通过修改my.cnf 在 [mysqld] 之下加 default-time-zone=timezone 来修改时区。如： default-time-zone = \'+8:00\'
通过命令:
set time_zone = timezone 比如北京时间（GMT+0800） set time_zone = \'+8:00\';
美国pst时间（GMT-08:00） set time_zone = \'-8:00\';
eg：
mysql> set time_zone = \'+8:00\'; Query OK, 0 rows affected (0.17 sec) mysql> select now(); +---------------------+ | now() | +---------------------+ | 2016-06-23 16:32:53 | +---------------------+ 1 row in set (0.00 sec) mysql> set time_zone = \'-8:00\'; Query OK, 0 rows affected (0.00 sec) mysql> select now(); +---------------------+ | now() | +---------------------+ | 2016-06-23 00:33:21 | +---------------------+ 1 row in set (0.00 sec)
mysql 数据库中的时区信息默认为空：
mysql> show tables like "%time%";
+---------------------------+
| Tables_in_mysql (%time%) |
+---------------------------+
| time_zone |
| time_zone_leap_second |
| time_zone_name |
| time_zone_transition |
| time_zone_transition_type |
+---------------------------+
5 rows in set (0.00 sec)
导入时区信息到MYSQL中
mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql -u root mysql查看导入后的信息:
mysql> SELECT * FROM time_zone_name WHERE name LIKE \'America/%\' limit 10; +----------------------------------+--------------+ | Name | Time_zone_id | +----------------------------------+--------------+ | America/Adak | 54 | | America/Anchorage | 55 | | America/Anguilla | 56 | | America/Antigua | 57 | | America/Araguaina | 58 | | America/Argentina/Buenos_Aires | 59 | | America/Argentina/Catamarca | 60 | | America/Argentina/ComodRivadavia | 61 | | America/Argentina/Cordoba | 62 | | America/Argentina/Jujuy | 63 | +----------------------------------+--------------+ 10 rows in set (0.00 sec)
美国不仅有时区,还有夏令时,冬令时,提前一小时,或者减慢一小时(在时区时间基础上)
美国2016年夏令时将于2016年03月13日当地时间早上02:00(北京时间14:00)开始，至2016年11月6日结束，届时美国的交易时间将较冬令时提前1个小时
mysql> SELECT CONVERT_TZ(\'2016-03-13 01:30:00\',\'-8:00\',\'America/Los_Angeles\') AS TIME\G *************************** 1. row *************************** TIME: 2016-03-13 01:30:00 1 row in set (0.00 sec)
mysql> SELECT CONVERT_TZ(\'2016-03-13 02:30:00\',\'-8:00\',\'America/Los_Angeles\') AS TIME\G
*************************** 1. row ***************************
TIME: 2016-03-13 03:30:00
1 row in set (0.00 sec)
内核专家:
目前在MySQL数据库中，在初始化time_zone相关表元信息以后，MySQL就可以自己完成夏令时（Daylight Saving Time）和闰秒（Leap Second）的修正，不需要额外的服务器
高手:
设置timezone后，不需要再通过__tz_convert()来转换，各个线程之间并无锁冲突， now()的影响将微乎其微。性能自然获得大大提升。
公司有人实验过，高并发下now()性能有8倍之差。
NOW()函数 不设时区信息需要__tz_convert()进行转换，带时区信息NOW(),就不需要__tz_convert()进行转换
now()不带时区转换过程：
now()或current_timestamp()等获取带有时区信息的时间时，数据库会在server层解析填充其field时，
通过内核层将gmt时间转化为所需的time类型。而转换是通内核层的libc动态库的接口__tz_convert()来实现。
这个实现一个致命的缺点是：串行化
select now();
Breakpoint 2, 0x00007f50e68a5ab0 in __tz_convert () from /lib64/libc.so.6 (gdb) bt #0 0x00007f50e68a5ab0 in __tz_convert () from /lib64/libc.so.6 #1 0x00000000008a40ef in Time_zone_system::gmt_sec_to_TIME (this=0x180ee30 <tz_SYSTEM>, tmp=0x48e0830, t=1467609071) at /usr/src/mysql-5.6.28/sql/tztime.cc:1079 #2 0x00000000006e9ce0 in Time_zone::gmt_sec_to_TIME (this=0x180ee30 <tz_SYSTEM>, tmp=0x48e0830, tv=...) at /usr/src/mysql-5.6.28/sql/tztime.h:60 #3 0x00000000006e5e61 in MYSQL_TIME_cache::set_datetime (this=0x48e0830, tv=..., dec_arg=0 \'\000\', tz=0x180ee30 <tz_SYSTEM>) at /usr/src/mysql-5.6.28/sql/item_timefunc.cc:1747 #4 0x00000000006e7bda in Item_func_now::fix_length_and_dec (this=0x48e0760) at /usr/src/mysql-5.6.28/sql/item_timefunc.cc:1866 #5 0x000000000069e0e7 in Item_func::fix_fields (this=0x48e0760, thd=0x492acb0, ref=0x48e0890) at /usr/src/mysql-5.6.28/sql/item_func.cc:231 #6 0x000000000075c155 in setup_fields (thd=0x492acb0, ref_pointer_array=..., fields=..., mark_used_columns=MARK_COLUMNS_READ, sum_func_list=0x48e0bb0, allow_sum_func=true) at /usr/src/mysql-5.6.28/sql/sql_base.cc:8400 #7 0x00000000007f749d in JOIN::prepare (this=0x48e0968, tables_init=0x0, wild_num=0, conds_init=0x0, og_num=0, order_init=0x0, group_init=0x0, having_init=0x0, select_lex_arg=0x492d248, unit_arg=0x492cc00) at /usr/src/mysql-5.6.28/sql/sql_resolver.cc:168 #8 0x00000000008080cd in mysql_prepare_select (thd=0x492acb0, tables=0x0, wild_num=0, fields=..., conds=0x0, og_num=0, order=0x0, group=0x0, having=0x0, select_options=2147748608, result=0x48e0940, unit=0x492cc00, select_lex=0x492d248, free_join=0x7f5081ec5e6b) at /usr/src/mysql-5.6.28/sql/sql_select.cc:1055 #9 0x0000000000808222 in mysql_select (thd=0x492acb0, tables=0x0, wild_num=0, fields=..., conds=0x0, order=0x492d410, group=0x492d348, having=0x0, select_options=2147748608, result=0x48e0940, unit=0x492cc00, select_lex=0x492d248) at /usr/src/mysql-5.6.28/sql/sql_select.cc:1178 #10 0x000000000080854d in handle_select (thd=0x492acb0, result=0x48e0940, setup_tables_done_option=0) at /usr/src/mysql-5.6.28/sql/sql_select.cc:110 #11 0x00000000007cdc4e in execute_sqlcom_select (thd=0x492acb0, all_tables=0x0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:5134 #12 0x00000000007cf185 in mysql_execute_command (thd=0x492acb0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:2656 #13 0x00000000007d67c4 in mysql_parse (thd=0x492acb0, rawbuf=0x48e06d0 "select now()", length=12, parser_state=0x7f5081ec7910) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:6386 #14 0x00000000007d83f4 in dispatch_command (command=COM_QUERY, thd=0x492acb0, packet=0x4910c51 "select now()", packet_length=12) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:1340 #15 0x00000000007d9c80 in do_command (thd=0x492acb0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:1037 #16 0x000000000078e3fb in do_handle_one_connection (thd_arg=0x492acb0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:982 #17 0x000000000078e4c1 in handle_one_connection (arg=0x492acb0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:898 #18 0x0000000000b11172 in pfs_spawn_thread (arg=0x47900b0) at /usr/src/mysql-5.6.28/storage/perfschema/pfs.cc:1860 #19 0x00007f50e744083d in start_thread () from /lib64/libpthread.so.0 #20 0x00007f50e68edfdd in clone () from /lib64/libc.so.6 #21 0x0000000000000000 in ?? ()
select sysdate();
(gdb) bt #0 0x00007f50e68a5ab0 in __tz_convert () from /lib64/libc.so.6 #1 0x00000000008a40ef in Time_zone_system::gmt_sec_to_TIME (this=0x180ee30 <tz_SYSTEM>, tmp=0x7f5081ec5770, t=1467609724) at /usr/src/mysql-5.6.28/sql/tztime.cc:1079 #2 0x00000000006e54de in Item_func_sysdate_local::get_date (this=0x48e0770, now_time=0x7f5081ec5770, fuzzy_date=1) at /usr/src/mysql-5.6.28/sql/item_timefunc.cc:1910 #3 0x0000000000634940 in Item::send (this=0x48e0770, protocol=0x492b1d0, buffer=0x7f5081ec5b70) at /usr/src/mysql-5.6.28/sql/item.cc:6925 #4 0x000000000070f558 in Protocol::send_result_set_row (this=0x492b1d0, row_items=0x492d368) at /usr/src/mysql-5.6.28/sql/protocol.cc:847 #5 0x00000000007833a9 in select_send::send_data (this=0x48e0900, items=...) at /usr/src/mysql-5.6.28/sql/sql_class.cc:2531 #6 0x00000000007a3ffa in JOIN::exec (this=0x48e0928) at /usr/src/mysql-5.6.28/sql/sql_executor.cc:149 #7 0x0000000000807992 in mysql_execute_select (thd=0x492acb0, select_lex=0x492d248, free_join=true) at /usr/src/mysql-5.6.28/sql/sql_select.cc:1101 #8 0x0000000000808351 in mysql_select (thd=0x492acb0, tables=0x0, wild_num=0, fields=..., conds=0x0, order=0x492d410, group=0x492d348, having=0x0, select_options=2147748608, result=0x48e0900, unit=0x492cc00, select_lex=0x492d248) at /usr/src/mysql-5.6.28/sql/sql_select.cc:1222 #9 0x000000000080854d in handle_select (thd=0x492acb0, result=0x48e0900, setup_tables_done_option=0) at /usr/src/mysql-5.6.28/sql/sql_select.cc:110 #10 0x00000000007cdc4e in execute_sqlcom_select (thd=0x492acb0, all_tables=0x0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:5134 #11 0x00000000007cf185 in mysql_execute_command (thd=0x492acb0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:2656 #12 0x00000000007d67c4 in mysql_parse (thd=0x492acb0, rawbuf=0x48e06d0 "select sysdate()", length=16, parser_state=0x7f5081ec7910) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:6386 #13 0x00000000007d83f4 in dispatch_command (command=COM_QUERY, thd=0x492acb0, packet=0x4910c51 "", packet_length=16) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:1340 #14 0x00000000007d9c80 in do_command (thd=0x492acb0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:1037 #15 0x000000000078e3fb in do_handle_one_connection (thd_arg=0x492acb0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:982 #16 0x000000000078e4c1 in handle_one_connection (arg=0x492acb0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:898 #17 0x0000000000b11172 in pfs_spawn_thread (arg=0x47900b0) at /usr/src/mysql-5.6.28/storage/perfschema/pfs.cc:1860 #18 0x00007f50e744083d in start_thread () from /lib64/libpthread.so.0 #19 0x00007f50e68edfdd in clone () from /lib64/libc.so.6 #20 0x0000000000000000 in ?? ()
select now() -2
(gdb) bt #0 0x00007ff8c1c1c1c0 in localtime_r () from /lib64/libc.so.6 #1 0x00000000008a40ef in Time_zone_system::gmt_sec_to_TIME (this=0x180ee30 <tz_SYSTEM>, tmp=0x49afae0, t=1467636107) at /usr/src/mysql-5.6.28/sql/tztime.cc:1079 #2 0x00000000006e9ce0 in Time_zone::gmt_sec_to_TIME (this=0x180ee30 <tz_SYSTEM>, tmp=0x49afae0, tv=...) at /usr/src/mysql-5.6.28/sql/tztime.h:60 #3 0x00000000006e5e61 in MYSQL_TIME_cache::set_datetime (this=0x49afae0, tv=..., dec_arg=0 \'\000\', tz=0x180ee30 <tz_SYSTEM>) at /usr/src/mysql-5.6.28/sql/item_timefunc.cc:1747 #4 0x00000000006e7bda in Item_func_now::fix_length_and_dec (this=0x49afa10) at /usr/src/mysql-5.6.28/sql/item_timefunc.cc:1866 #5 0x000000000069e0e7 in Item_func::fix_fields (this=0x49afa10, thd=0x48c3db0, ref=0x49afb40) at /usr/src/mysql-5.6.28/sql/item_func.cc:231 #6 0x000000000075c155 in setup_fields (thd=0x48c3db0, ref_pointer_array=..., fields=..., mark_used_columns=MARK_COLUMNS_READ, sum_func_list=0x49afe60, allow_sum_func=true) at /usr/src/mysql-5.6.28/sql/sql_base.cc:8400 #7 0x00000000007f749d in JOIN::prepare (this=0x49afc18, tables_init=0x0, wild_num=0, conds_init=0x0, og_num=0, order_init=0x0, group_init=0x0, having_init=0x0, select_lex_arg=0x48c6348, unit_arg=0x48c5d00) at /usr/src/mysql-5.6.28/sql/sql_resolver.cc:168 #8 0x00000000008080cd in mysql_prepare_select (thd=0x48c3db0, tables=0x0, wild_num=0, fields=..., conds=0x0, og_num=0, order=0x0, group=0x0, having=0x0, select_options=2147748608, result=0x49afbf0, unit=0x48c5d00, select_lex=0x48c6348, free_join=0x7ff85d1fce6b) at /usr/src/mysql-5.6.28/sql/sql_select.cc:1055 #9 0x0000000000808222 in mysql_select (thd=0x48c3db0, tables=0x0, wild_num=0, fields=..., conds=0x0, order=0x48c6510, group=0x48c6448, having=0x0, select_options=2147748608, result=0x49afbf0, unit=0x48c5d00, select_lex=0x48c6348) at /usr/src/mysql-5.6.28/sql/sql_select.cc:1178 #10 0x000000000080854d in handle_select (thd=0x48c3db0, result=0x49afbf0, setup_tables_done_option=0) at /usr/src/mysql-5.6.28/sql/sql_select.cc:110 #11 0x00000000007cdc4e in execute_sqlcom_select (thd=0x48c3db0, all_tables=0x0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:5134 #12 0x00000000007cf185 in mysql_execute_command (thd=0x48c3db0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:2656 #13 0x00000000007d67c4 in mysql_parse (thd=0x48c3db0, rawbuf=0x49af980 "select now()", length=12, parser_state=0x7ff85d1fe910) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:6386 #14 0x00000000007d83f4 in dispatch_command (command=COM_QUERY, thd=0x48c3db0, packet=0x49a5751 "select now()", packet_length=12) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:1340 #15 0x00000000007d9c80 in do_command (thd=0x48c3db0) at /usr/src/mysql-5.6.28/sql/sql_parse.cc:1037 #16 0x000000000078e3fb in do_handle_one_connection (thd_arg=0x48c3db0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:982 #17 0x000000000078e4c1 in handle_one_connection (arg=0x48c3db0) at /usr/src/mysql-5.6.28/sql/sql_connect.cc:898 #18 0x0000000000b11172 in pfs_spawn_thread (arg=0x4794e60) at /usr/src/mysql-5.6.28/storage/perfschema/pfs.cc:1860 #19 0x00007ff8c27b883d in start_thread () from /lib64/libpthread.so.0 #20 0x00007ff8c1c65fdd in clone () from /lib64/libc.so.6 #21 0x0000000000000000 in ?? () (gdb) disas Dump of assembler code for function localtime_r: => 0x00007ff8c1c1c1c0 <+0>: mov %rsi,%rdx 0x00007ff8c1c1c1c3 <+3>: mov $0x1,%esi 0x00007ff8c1c1c1c8 <+8>: jmpq 0x7ff8c1c1dab0 <__tz_convert> End of assembler dump. (gdb) next Single stepping until exit from function localtime_r, which has no line number information. 0x00007ff8c1c1dab0 in __tz_convert () from /lib64/libc.so.6 (gdb) diaas Undefined command: "diaas". Try "help". (gdb) disas Dump of assembler code for function __tz_convert: => 0x00007ff8c1c1dab0 <+0>: push %r12 0x00007ff8c1c1dab2 <+2>: mov %esi,%r12d 0x00007ff8c1c1dab5 <+5>: push %rbp 0x00007ff8c1c1dab6 <+6>: mov %rdi,%rbp 0x00007ff8c1c1dab9 <+9>: push %rbx 0x00007ff8c1c1daba <+10>: mov %rdx,%rbx 0x00007ff8c1c1dabd <+13>: sub $0x10,%rsp 0x00007ff8c1c1dac1 <+17>: test %rdi,%rdi 0x00007ff8c1c1dac4 <+20>: je 0x7ff8c1c1dc6e <__tz_convert+446> 0x00007ff8c1c1daca <+26>: mov $0x1,%esi 0x00007ff8c1c1dacf <+31>: xor %eax,%eax 0x00007ff8c1c1dad1 <+33>: cmpl $0x0,0x2cb458(%rip) # 0x7ff8c1ee8f30 <__libc_multiple_threads> 0x00007ff8c1c1dad8 <+40>: je 0x7ff8c1c1daea <__tz_convert+58> 0x00007ff8c1c1dada <+42>: lock cmpxchg %esi,0x2c8ab2(%rip) # 0x7ff8c1ee6594 <tzset_lock> 0x00007ff8c1c1dae2 <+50>: jne 0x7ff8c1c1dd9a <_L_lock_1685> 0x00007ff8c1c1dae8 <+56>: jmp 0x7ff8c1c1daf7 <__tz_convert+71> 0x00007ff8c1c1daea <+58>: cmpxchg %esi,0x2c8aa3(%rip) # 0x7ff8c1ee6594 <tzset_lock> 0x00007ff8c1c1daf1 <+65>: jne 0x7ff8c1c1dd9a <_L_lock_1685> 0x00007ff8c1c1daf7 <+71>: lea 0x2cb1c2(%rip),%rax # 0x7ff8c1ee8cc0 <_tmbuf> 0x00007ff8c1c1dafe <+78>: xor %edi,%edi 0x00007ff8c1c1db00 <+80>: cmp %rax,%rdx 0x00007ff8c1c1db03 <+83>: sete %dil 0x00007ff8c1c1db07 <+87>: xor %esi,%esi 0x00007ff8c1c1db09 <+89>: callq 0x7ff8c1c1d160 <tzset_internal> 0x00007ff8c1c1db0e <+94>: mov 0x2cb1ec(%rip),%eax # 0x7ff8c1ee8d00 <__use_tzfile> 0x00007ff8c1c1db14 <+100>: test %eax,%eax 0x00007ff8c1c1db16 <+102>: je 0x7ff8c1c1db94 <__tz_convert+228> 0x00007ff8c1c1db18 <+104>: mov 0x0(%rbp),%rdi 0x00007ff8c1c1db1c <+108>: lea 0xc(%rsp),%rcx 0x00007ff8c1c1db21 <+113>: mov %rsp,%rdx 0x00007ff8c1c1db24 <+116>: mov %rbx,%r8 0x00007ff8c1c1db27 <+119>: mov %r12d,%esi 0x00007ff8c1c1db2a <+122>: callq 0x7ff8c1c1de60 <__tzfile_compute> 0x00007ff8c1c1db2f <+127>: test %rbx,%rbx 0x00007ff8c1c1db32 <+130>: je 0x7ff8c1c1db64 <__tz_convert+180> 0x00007ff8c1c1db34 <+132>: test %r12d,%r12d 0x00007ff8c1c1db37 <+135>: je 0x7ff8c1c1dbc8 <__tz_convert+280> 0x00007ff8c1c1db3d <+141>: mov 0x2cb1bd(%rip),%eax # 0x7ff8c1ee8d00 <__use_tzfile> 0x00007ff8c1c1db43 <+147>: test %eax,%eax 0x00007ff8c1c1db45 <+149>: je 0x7ff8c1c1dc13 <__tz_convert+355> 0x00007ff8c1c1db4b <+155>: mov 0x28(%rbx),%rsi 0x00007ff8c1c1db4f <+159>: sub (%rsp),%rsi 0x00007ff8c1c1db53 <+163>: mov %rbx,%rdx 0x00007ff8c1c1db56 <+166>: mov %rbp,%rdi 0x00007ff8c1c1db59 <+169>: callq 0x7ff8c1c1ba90 <__offtime> 0x00007ff8c1c1db5e <+174>: test %eax,%eax 0x00007ff8c1c1db60 <+176>: jne 0x7ff8c1c1dbc0 <__tz_convert+272> 0x00007ff8c1c1db62 <+178>: xor %ebx,%ebx 0x00007ff8c1c1db64 <+180>: cmpl $0x0,0x2cb3c5(%rip) # 0x7ff8c1ee8f30 <__libc_multiple_threads> 0x00007ff8c1c1db6b <+187>: je 0x7ff8c1c1db7c <__tz_convert+204> 0x00007ff8c1c1db6d <+189>: lock decl 0x2c8a20(%rip) # 0x7ff8c1ee6594 <tzset_lock> 0x00007ff8c1c1db74 <+196>: jne 0x7ff8c1c1ddb9 <_L_unlock_1746> 0x00007ff8c1c1db7a <+202>: jmp 0x7ff8c1c1db88 <__tz_convert+216> 0x00007ff8c1c1db7c <+204>: decl 0x2c8a12(%rip) # 0x7ff8c1ee6594 <tzset_lock> 0x00007ff8c1c1db82 <+210>: jne 0x7ff8c1c1ddb9 <_L_unlock_1746> 0x00007ff8c1c1db88 <+216>: add $0x10,%rsp 0x00007ff8c1c1db8c <+220>: mov %rbx,%rax 0x00007ff8c1c1db8f <+223>: pop %rbx 0x00007ff8c1c1db90 <+224>: pop %rbp 0x00007ff8c1c1db91 <+225>: pop %r12 0x00007ff8c1c1db93 <+227>: retq 0x00007ff8c1c1db94 <+228>: xor %esi,%esi 0x00007ff8c1c1db96 <+230>: mov %rbx,%rdx 0x00007ff8c1c1db99 <+233>: mov %rbp,%rdi 0x00007ff8c1c1db9c <+236>: callq 0x7ff8c1c1ba90 <__offtime> 0x00007ff8c1c1dba1 <+241>: test %eax,%eax 0x00007ff8c1c1dba3 <+243>: jne 0x7ff8c1c1dbe7 <__tz_convert+311> 0x00007ff8c1c1dba5 <+245>: xor %ebx,%ebx 0x00007ff8c1c1dba7 <+247>: movq $0x0,(%rsp) 0x00007ff8c1c1dbaf <+255>: movl $0x0,0xc(%rsp) 0x00007ff8c1c1dbb7 <+263>: jmpq 0x7ff8c1c1db2f <__tz_convert+127> 0x00007ff8c1c1dbbc <+268>: nopl 0x0(%rax) 0x00007ff8c1c1dbc0 <+272>: mov 0xc(%rsp),%eax 0x00007ff8c1c1dbc4 <+276>: add %eax,(%rbx) 0x00007ff8c1c1dbc6 <+278>: jmp 0x7ff8c1c1db64 <__tz_convert+180> 0x00007ff8c1c1dbc8 <+280>: lea 0x951ae(%rip),%rax # 0x7ff8c1cb2d7d 0x00007ff8c1c1dbcf <+287>: movl $0x0,0x20(%rbx) 0x00007ff8c1c1dbd6 <+294>: movq $0x0,0x28(%rbx) 0x00007ff8c1c1dbde <+302>: mov %rax,0x30(%rbx) 0x00007ff8c1c1dbe2 <+306>: jmpq 0x7ff8c1c1db4b <__tz_convert+155> 0x00007ff8c1c1dbe7 <+311>: mov 0x14(%rbx),%esi 0x00007ff8c1c1dbea <+314>: lea 0x2c89af(%rip),%rdi # 0x7ff8c1ee65a0 <tz_rules> 0x00007ff8c1c1dbf1 <+321>: add $0x76c,%esi 0x00007ff8c1c1dbf7 <+327>: callq 0x7ff8c1c1ce00 <compute_change> 0x00007ff8c1c1dbfc <+332>: mov 0x14(%rbx),%esi 0x00007ff8c1c1dbff <+335>: lea 0x2c89ca(%rip),%rdi # 0x7ff8c1ee65d0 <tz_rules+48> 0x00007ff8c1c1dc06 <+342>: add $0x76c,%esi 0x00007ff8c1c1dc0c <+348>: callq 0x7ff8c1c1ce00 <compute_change> 0x00007ff8c1c1dc11 <+353>: jmp 0x7ff8c1c1dba7 <__tz_convert+247> 0x00007ff8c1c1dc13 <+355>: mov 0x2c89a6(%rip),%rcx # 0x7ff8c1ee65c0 <tz_rules+32> 0x00007ff8c1c1dc1a <+362>: mov 0x2c89cf(%rip),%rdi # 0x7ff8c1ee65f0 <tz_rules+80> 0x00007ff8c1c1dc21 <+369>: cmp %rdi,%rcx 0x00007ff8c1c1dc24 <+372>: jg 0x7ff8c1c1dc83 <__tz_convert+467> 0x00007ff8c1c1dc26 <+374>: mov 0x0(%rbp),%rsi 0x00007ff8c1c1dc2a <+378>: xor %eax,%eax 0x00007ff8c1c1dc2c <+380>: cmp %rsi,%rcx 0x00007ff8c1c1dc2f <+383>: jg 0x7ff8c1c1dc39 <__tz_convert+393> 0x00007ff8c1c1dc31 <+385>: xor %eax,%eax 0x00007ff8c1c1dc33 <+387>: cmp %rsi,%rdi 0x00007ff8c1c1dc36 <+390>: setg %al 0x00007ff8c1c1dc39 <+393>: movslq %eax,%rdx 0x00007ff8c1c1dc3c <+396>: mov %eax,0x20(%rbx) 0x00007ff8c1c1dc3f <+399>: mov 0x2c617a(%rip),%rax # 0x7ff8c1ee3dc0 0x00007ff8c1c1dc46 <+406>: mov (%rax,%rdx,8),%rax 0x00007ff8c1c1dc4a <+410>: mov %rax,0x30(%rbx) 0x00007ff8c1c1dc4e <+414>: lea (%rdx,%rdx,1),%rax 0x00007ff8c1c1dc52 <+418>: add %rdx,%rax 0x00007ff8c1c1dc55 <+421>: lea 0x2c894c(%rip),%rdx # 0x7ff8c1ee65a8 <tz_rules+8> 0x00007ff8c1c1dc5c <+428>: shl $0x4,%rax 0x00007ff8c1c1dc60 <+432>: mov 0x10(%rax,%rdx,1),%rax 0x00007ff8c1c1dc65 <+437>: mov %rax,0x28(%rbx) 0x00007ff8c1c1dc69 <+441>: jmpq 0x7ff8c1c1db4b <__tz_convert+155> 0x00007ff8c1c1dc6e <+446>: mov 0x2c6333(%rip),%rax # 0x7ff8c1ee3fa8 0x00007ff8c1c1dc75 <+453>: xor %ebx,%ebx 0x00007ff8c1c1dc77 <+455>: movl $0x16,%fs:(%rax) 0x00007ff8c1c1dc7e <+462>: jmpq 0x7ff8c1c1db88 <__tz_convert+216> 0x00007ff8c1c1dc83 <+467>: mov 0x0(%rbp),%rdx 0x00007ff8c1c1dc87 <+471>: mov $0x1,%eax 0x00007ff8c1c1dc8c <+476>: cmp %rdx,%rdi 0x00007ff8c1c1dc8f <+479>: jg 0x7ff8c1c1dc39 <__tz_convert+393> 0x00007ff8c1c1dc91 <+481>: xor %eax,%eax 0x00007ff8c1c1dc93 <+483>: cmp %rdx,%rcx 0x00007ff8c1c1dc96 <+486>: setle %al 0x00007ff8c1c1dc99 <+489>: jmp 0x7ff8c1c1dc39 <__tz_convert+393> End of assembler dump.
[root@localhost ~]# stap -v -e \'probe process("/lib64/libc-2.5.so").function("__tz_convert").call{ if( tid()==15267) printf("%s:%s %d \n",execname(),probefunc(),tid());print_ubacktrace()}\' -d /usr/local/mysql56/bin/mysqld |c++filt Pass 1: parsed user script and 109 library script(s) using 110724virt/34364res/2112shr/32900data kb, in 260usr/100sys/385real ms. Pass 2: analyzed script: 1 probe(s), 9 function(s), 4 embed(s), 0 global(s) using 113460virt/38036res/3108shr/35636data kb, in 60usr/1050sys/2125real ms. Pass 3: using cached /root/.systemtap/cache/a1/stap_a10e8693bbc550250f91b5363abb795b_3427.c Pass 4: using cached /root/.systemtap/cache/a1/stap_a10e8693bbc550250f91b5363abb795b_3427.ko Pass 5: starting run. WARNING: Missing unwind data for module, rerun with \'stap -d /usr/local/mysql56/bin/mysql\' mysqld:__tz_convert 15267 0x7fbcecdb1ab0 : __tz_convert+0x0/0x1f0 [/lib64/libc-2.5.so] 0x8a40ef : Time_zone_system::gmt_sec_to_TIME(st_mysql_time*, long) const+0x29/0x4c [/usr/local/mysql56/bin/mysqld] 0x6e9ce0 : Time_zone::gmt_sec_to_TIME(st_mysql_time*, timeval)+0x3a/0x4c [/usr/local/mysql56/bin/mysqld] 0x6e5e61 : MYSQL_TIME_cache::set_datetime(timeval, unsigned char, Time_zone*)+0x33/0x5e [/usr/local/mysql56/bin/mysqld] 0x6e7bda : Item_func_now::fix_length_and_dec()+0x98/0xba [/usr/local/mysql56/bin/mysqld] 0x69e0e7 : Item_func::fix_fields(THD*, Item**)+0x4d1/0x548 [/usr/local/mysql56/bin/mysqld] 0x75c155 : setup_fields(THD*, Bounds_checked_array<Item*>, List<Item>&, enum_mark_columns, List<Item>*, bool)+0x313/0x688 [/usr/local/mysql56/bin/mysqld] 0x7f749d : JOIN::prepare(TABLE_LIST*, unsigned int, Item*, unsigned int, st_order*, st_order*, Item*, st_select_lex*, st_select_lex_unit*)+0x6c3/0x1768 [/usr/local/mysql56/bin/mysqld] 0x8080cd : mysql_prepare_select(THD*, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*, bool*)+0x2f9/0x34a [/usr/local/mysql56/bin/mysqld] 0x808222 : mysql_select(THD*, TABLE_LIST*, unsigned int, List<Item>&, Item*, SQL_I_List<st_order>*, SQL_I_List<st_order>*, Item*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*)+0x104/0x23e [/usr/local/mysql56/bin/mysqld] 0x80854d : handle_select(THD*, select_result*, unsigned long)+0x1f1/0x29e [/usr/local/mysql56/bin/mysqld] 0x7cdc4e : execute_sqlcom_select(THD*, TABLE_LIST*)+0x336/0x3ba [/usr/local/mysql56/bin/mysqld] 0x7cf185 : mysql_execute_command(THD*)+0xc91/0x7ec8 [/usr/local/mysql56/bin/mysqld] 0x7d67c4 : mysql_parse(THD*, char*, unsigned int, Parser_state*)+0x408/0x690 [/usr/local/mysql56/bin/mysqld] 0x7d83f4 : dispatch_command(enum_server_command, THD*, char*, unsigned int)+0xd0a/0x227e [/usr/local/mysql56/bin/mysqld] 0x7d9c80 : do_command(THD*)+0x318/0x394 [/usr/local/mysql56/bin/mysqld] 0x78e3fb : do_handle_one_connection(THD*)+0x1ad/0x246 [/usr/local/mysql56/bin/mysqld] 0x78e4c1 : handle_one_connection+0x2d/0x34 [/usr/local/mysql56/bin/mysqld] 0xb11172 : pfs_spawn_thread+0x18c/0x194 [/usr/local/mysql56/bin/mysqld] 0x7fbced94c83d [/lib64/libpthread-2.5.so+0x683d/0x218000] 0x7fc104aaeab0 : __tz_convert+0x0/0x1f0 [/lib64/libc-2.5.so] 0x410901 [/usr/local/mysql56/bin/mysql+0x10901/0x15e000] ^CPass 5: run completed in 10usr/120sys/10618real ms.