[20180826]GUID做主键.txt

[20180826]GUID做主键.txt --//我个人是反对使用GUID做主键的,我们有一个应用使用guid做主键,而且保存的类型不是raw类型,而是转换为varchar2(36), --//中间还使用"-"分隔.重复链接的测试:https://connor-mcdonald.com/2018/08/21/gooey-guids/ --//当然我个人也很矛盾,如果一个应用有许多sequence做主键(甚至上千),维护也是一个大问题. 1.环境: SCOTT@test01p> @ ver1 PORT_STRING                    VERSION        BANNER                                                                               CON_ID ------------------------------ -------------- -------------------------------------------------------------------------------- ---------- IBMPC/WIN_NT64-9.1.0           12.1.0.1.0     Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production              0 SCOTT@test01p> create table t ( sz int, dur interval day to second ); Table created. 2.测试脚本: declare   ts_start timestamp;   ts_end   timestamp;   iter int;   dummy raw(32); begin  for i in 1 .. 7 loop --// for i in 1 .. 8 loop   iter := power(10,i);   ts_start := systimestamp;   if iter <= 10000 then      select max(x) into dummy from      (      select sys_guid() x from      ( select 1 from dual connect by level <= iter )      );   else      select max(x) into dummy from      (      select sys_guid() x from      ( select 1 from dual connect by level <= iter/10000 ),      ( select 1 from dual connect by level <= 10000 )      );   end if;   ts_end := systimestamp;   insert into t values (iter, ts_end - ts_start );   commit;  end loop; end; / --//我仅仅测试执行7次(8次时间太长了). SCOTT@test01p> select * from t;         SZ DUR ---------- --------------------         10 +00 00:00:00.010000        100 +00 00:00:00.003000       1000 +00 00:00:00.030000      10000 +00 00:00:00.250000     100000 +00 00:00:02.264000    1000000 +00 00:00:24.194000   10000000 +00 00:03:54.217000 7 rows selected. --//当然集中看消耗CPU资源,如果主键全部都是消耗还是很可观的.我个人不建议使用它.