( order by id ) case3 from mynumber) as tt where case1<=10 (1) 取前10条不同id记录,假如最后1条记录的ID依然有相同的,那么全部取出来。 select * from mynumber where id in (select distinct id from mynumber fetch first 10 rows only) select * from (select id,name,RANK() over ( orde...
DB2 Sql性能查看与优化 1.执行次数最多的TOP10SQL" db2 "select * from sysibmadm.snapdyn_sql order by NUM_EXECUTIONS desc fetch first 10 rows only" 2、平均执行时间最长的TOP10SQL" db2 "select * from sysibmadm.top_dynamic_sql order by average_execution_time_s desc fetch first 10 rows only" ...
1.执行次数最多的TOP10SQL" db2 "select * from sysibmadm.snapdyn_sql order by NUM_EXECUTIONS desc fetch first 10 rows only" 2、平均执行时间最长的TOP10SQL" db2 "select * from sysibmadm.top_dynamic_sql order by average_execution_time_s desc fetch first 10 rows only" 3、排序最多的TOP10SQL...
因此为了使用户更方便地理解应用程序之间的锁关系,db2top工具提供了一个有用的特性:动态地绘制锁链。 通过输入大写L可展示锁链,如图12所示: 图12.锁等待–Lock chain 3.7表监控 (T) 表监控模式显示数据库中的表信息。在当前时间内未被访问的空闲表以白色显示。正在访问(活动)的表以绿色显示。 列Delta RowsRead(...
(1) 取前10条不同id记录,假如最后1条记录的ID依然有相同的,那么取出来。 select id,name from mynumber where id in (select id from (select distinct id from mynumber) tt where rownum<=10); select * from (select id,name,RANK() over ( order by id ) case1,DENSE_RANK() ...
db2: select * from tab fetch first 10 rows only oracle: select * from tab where rownum =10 sqlserver: select top 1
2、执行次数最多的TOP10SQL" db2 "select substr(stmt_text,1,500) as stmt_text,NUM_EXECUTIONS,TOTAL_USR_CPU_TIME,TOTAL_EXEC_TIME,SORT_OVERFLOWS from sysibmadm.snapdyn_sql order by NUM_EXECUTIONS desc fetch first 10 rows only"|grep -iv selected ...
DB2中请使用 select * from A fetch first 10 rows only
在学Oracle ,突然发现Top 关键字用不了。哎!原来是中了SqlServer的毒 db2: select * from tab fetch first 10 rows only oracle: select * from tab where rownum <=10 sqlserver: select top 10 * from tab mysql: select * from tab limit 10...
如果想要从热点数据的角度去分析问题，找到对应的表，然后再找到对应的热点语句，就可以分析是否存在问题，是否需要优化。db2top 首页键入 T 可以进入 Tables 的监控界面。在这个界面里能看到 Delta RowsRead 和 Delta RowsWritten 等信息，从而获取当前热点表信息。清单 12. db2top 查看热点表[/]15:52:03,refresh...