db2数据库常用调试检测数据库语句

connect to [数据库名] user [操作用户名] using [密码]

连接到数据库指定数据库，不包含中括号

reorgchk on table EAS.T_User

检测是否需要重组表EAS.T_User

reorgchk update statistics on table all

检测所有表是否需要重组

select tabname, colcount, status  FROM syscat.tables   WHERE tabschema NOT LIKE 'SYS%'  ORDER BY tabname

状态是否正常状态列 N = 正常；C = 待审核

get snapshot for bufferpools on 数据库名

检测快照缓冲池命中率>95%？

get snapshot for Locks on EASdb

检测快照锁

get snapshot for Locks on EASdb
get snapshot for all  on EASdb

检测快照锁

select index_hit_ratio_percent  from sysibmadm.bp_hitratio 

缓冲池命中率

select agent_id,rows_selected,rows_read from sysibmadm.application_performance

查看系统性能

select elapsed_time_min,appl_status,agent_id from sysibmadm.long_running_sql order by elapsed_time_min desc fetch first 5 rows only

查看运行时间最长的应用

select * from sysibmadm.top_dynamic_sql order by num_executions desc 

查看运行次数最多的SQL

select tabschema, tabname  from syscat.tables where stats_time is null

查看没有统计信息的表

select  tabname  from syscat.indexes where stats_time is null

查看没有统计信息的索引

reorg table EAS.T_City

重组单表

 reorg indexes all for table 表名

只重组索引

runstats on table EAS.t_group and detailed indexes all

重新统计表和索引

list applications show detail

显示所用应用情况

list tablespaces show detail

显示所用表空间情况

create unique index t_groupIdCODEname  on eas.t_group  (G_ID asc,G_CODE,G_NAME)  allow reverse scans

创建可以反向扫描的唯一索引，在需要排序时

create index t_groupIdCODEname  on eas.t_group  (G_ID asc) include(G_CODE,G_NAME)

创建include的索引

create table eas.t1(c1 int,c2 double,c3 double generated always as c1+c2,c4 generated always as( case when c1>c2  then 1 else null end))

创建具有计算列的表

一般再有大量的删除，修改，增加时需要reorg table，在进行runstats on table