ORACLE CUP相关
遭遇cpu过多占用,表现为%usr很高,top 或者topas中cpu占用最多的进程为oracle server process. 则根据pid可以找出该pid对应的sql_text select se.username,se.machine,sq.cpu_time,sq.sql_text from v$process p,v$session se,v$sqlarea sq where p.addr=se.paddr and se.sql_hash_value=sq.hash_value and p.addr=‘&pid‘; 下面的句子列出cpu_time占用top 10的sql select cpu_time,sql_text from (select sql_text,cpu_time, rank() over (order by cpu_time desc) exec_rank from v$sql ) where exec_rank <=10; 执行次数最多的top 10 select sql_text,executions from (select sql_text,executions, rank() over (order by executions desc) exec_rank from v$sql) where exec_rank <=10;
1. 监控事例的等待 select event, sum(decode(wait_Time, 0, 0, 1)) "Prev", sum(decode(wait_Time, 0, 1, 0)) "Curr", count(*) "Tot" from v$session_Wait group by event order by 4; 2. 回滚段的争用情况 select name, waits, gets, waits / gets "Ratio" from v$rollstat a, v$rollname b where a.usn = b.usn; 3. 监控表空间的 I/O 比例 select df.tablespace_name name, df.file_name "file", f.phyrds pyr, f.phyblkrd pbr, f.phywrts pyw, f.phyblkwrt pbw from v$filestat f, dba_data_files df where f.file# = df.file_id order by df.tablespace_name; 4. 监控文件系统的 I/O 比例 select substr(a.file#, 1, 2) "#", substr(a.name, 1, 30) "Name", a.status, a.bytes, b.phyrds, b.phywrts from v$datafile a, v$filestat b where a.file# = b.file#; 5.在某个用户下找所有的索引 select user_indexes.table_name, user_indexes.index_name, uniqueness, column_name from user_ind_columns, user_indexes where user_ind_columns.index_name = user_indexes.index_name and user_ind_columns.table_name = user_indexes.table_name order by user_indexes.table_type, user_indexes.table_name, user_indexes.index_name, column_position; 6. 监控 SGA 的命中率 select a.value + b.value "logical_reads", c.value "phys_reads", round(100 * ((a.value + b.value) - c.value) / (a.value + b.value)) "BUFFER HIT RATIO" from v$sysstat a, v$sysstat b, v$sysstat c where a.statistic# = 38 and b.statistic# = 39 and c.statistic# = 40; 7. 监控 SGA 中字典缓冲区的命中率 select parameter, gets, Getmisses, getmisses / (gets + getmisses) * 100 "miss ratio", (1 - (sum(getmisses) / (sum(gets) + sum(getmisses)))) * 100 "Hit ratio" from v$rowcache where gets + getmisses <> 0 group by parameter, gets, getmisses; 8. 监控 SGA 中共享缓存区的命中率,应该小于1% select sum(pins) "Total Pins", sum(reloads) "Total Reloads", sum(reloads) / sum(pins) * 100 libcache from v$librarycache; select sum(pinhits - reloads) / sum(pins) "hit radio", sum(reloads) / sum(pins) "reload percent" from v$librarycache; 9. 显示所有数据库对象的类别和大小 select count(name) num_instances, type, sum(source_size) source_size, sum(parsed_size) parsed_size, sum(code_size) code_size, sum(error_size) error_size, sum(source_size) + sum(parsed_size) + sum(code_size) + sum(error_size) size_required from dba_object_size group by type order by 2; 10. 监控 SGA 中重做日志缓存区的命中率,应该小于1% SELECT name, gets, misses, immediate_gets, immediate_misses, Decode(gets, 0, 0, misses / gets * 100) ratio1, Decode(immediate_gets + immediate_misses, 0, 0, immediate_misses / (immediate_gets + immediate_misses) * 100) ratio2 FROM v$latch WHERE name IN (‘redo allocation‘, ‘redo copy‘); 11. 监控内存和硬盘的排序比率,最好使它小于 .10,增加 sort_area_size SELECT name, value FROM v$sysstat WHERE name IN (‘sorts (memory)‘, ‘sorts (disk)‘); 12. 监控当前数据库谁在运行什么SQL语句 SELECT osuser, username, sql_text from v$session a, v$sqltext b where a.sql_address = b.address order by address, piece; 13. 监控字典缓冲区 SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE" FROM V$LIBRARYCACHE; SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW CACHE" FROM V$ROWCACHE; SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSES WHILE EXECUTING" FROM V$LIBRARYCACHE; 后者除以前者,此比率小于1%,接近0%为好。 SELECT SUM(GETS) "DICTIONARY GETS", SUM(GETMISSES) "DICTIONARY CACHE GET MISSES" FROM V$ROWCACHE 14. 找ORACLE字符集 select * from sys.props$ where name=‘NLS_CHARACTERSET‘; 15. 监控 MTS select busy/(busy+idle) "shared servers busy" from v$dispatcher; 此值大于0.5时,参数需加大 select sum(wait)/sum(totalq) "dispatcher waits" from v$queue where type=‘dispatcher‘; select count(*) from v$dispatcher; select servers_highwater from v$mts; servers_highwater接近mts_max_servers时,参数需加大 16. 碎片程度 select tablespace_name,count(tablespace_name) from dba_free_space group by tablespace_name having count(tablespace_name)>10; alter tablespace name coalesce; alter table name deallocate unused; create or replace view ts_blocks_v as select tablespace_name,block_id,bytes,blocks,‘free space‘ segment_name from dba_free_space union all select tablespace_name,block_id,bytes,blocks,segment_name from dba_extents; select * from ts_blocks_v; select tablespace_name,sum(bytes),max(bytes),count(block_id) from dba_free_space group by tablespace_name; 查看碎片程度高的表 SELECT segment_name table_name, COUNT(*) extents FROM dba_segments WHERE owner NOT IN (‘SYS‘, ‘SYSTEM‘) GROUP BY segment_name HAVING COUNT(*) = (SELECT MAX(COUNT(*)) FROM dba_segments GROUP BY segment_name); 17. 表、索引的存储情况检查 select segment_name, sum(bytes), count(*) ext_quan from dba_extents where tablespace_name = ‘&tablespace_name‘ and segment_type = ‘TABLE‘ group by tablespace_name, segment_name; select segment_name, count(*) from dba_extents where segment_type = ‘INDEX‘ and owner = ‘&owner‘ group by segment_name; 18、找使用CPU多的用户session 12是cpu used by this session select a.sid, spid, status, substr(a.program, 1, 40) prog, a.terminal, osuser, value / 60 / 100 value from v$session a, v$process b, v$sesstat c where c.statistic# = 12 and c.sid = a.sid and a.paddr = b.addr order by value desc;
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