2009年3月11日
摘要：
If there are latch free waits, then this script can be used to further diagnose the problem. For each latch type, it reports the estimated impact of sleeps, and the number of sleeps per get. It also r... 阅读全文
摘要：
This script compares spin gets to sleep gets as an indicator of the effectiveness of spinning, for each latch type. column name format a39 heading "LATCH TYPE" column spin_gets ... 阅读全文
摘要：
This script reports the breakdown of willing-to-wait gets for each latch type, into simple gets, spin gets and sleep gets. Spin gets and sleep gets are latch gets that require spinning or sleeping res... 阅读全文
摘要：
This scripts prints a list of the latch types, and reports the number of child latches for each type. If a latch type has multiple child latches, V$LATCH_CHILDREN can be used to determine whether ac... 阅读全文
摘要：
This script is one of our favorites. It finds the top N sessions that have been affected by a particular type of resource wait, and enables event 10046, level 8 in those sessions for the specified per... 阅读全文
摘要：
select e.event, e.time_waited from sys.v_$session_event e where e.sid = &Sid union all select n.name, s.value from sys.v_$statname n, sys.v_$sesstat s where s.sid = &Sid and n.s... 阅读全文
摘要：
reselect substr(e.event, 1, 40) event, e.time_waited, e.time_waited / decode( e.event, 'latch free', e.total_waits, decode( e.total_waits - e.total_timeouts, 0, 1, ... 阅读全文
摘要：
select substr(e.event, 1, 40) event, e.average_wait from sys.v_$system_event e, sys.v_$instance i where e.event = 'DFS lock handle' or e.event = 'rdbms ipc reply' or e.event like 'SQL... 阅读全文
摘要：
select x.ksppinm name, y.kspftctxvl value, y.kspftctxdf isdefault, decode(bitand(y.kspftctxvf,7),1,'MODIFIED',4,'SYSTEM_MOD','FALSE') ismod, decode(bitand(y.kspftctxvf,2),2,'TRUE','FALSE... 阅读全文
摘要：
select x.ksppinm name, decode(bitand(ksppiflg/256,1),1,'TRUE','FALSE') sesmod, decode( bitand(ksppiflg/65536,3), 1,'IMMEDIATE', 2,'DEFERRED', 3,'IMMEDIATE', 'FALSE' ) s... 阅读全文
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1. 选用适合的ORACLE优化器 ORACLE的优化器共有3种: a. RULE (基于规则) b. COST (基于成本) c. CHOOSE (选择性) 设置缺省的优化器,可以通过对init.ora文件中OPTIMIZER_MODE参数的各种声明,如RULE,COST,CHOOSE,ALL_ROWS,FIRST_ROWS . ... 阅读全文
摘要：
create or replace procedure put_line_unlimit( p_string in varchar2 ) is l_string long default p_string; begin loop exit when l_string is null; dbms_output.put_line( substr( l_string, 1... 阅读全文