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/dev/null
[5]+ Done sqlplus / as sysdba <<< "@ exclusive_latch.txt 'test excl. parent2 l0' 0 5 6 6" > /dev/null
[2]+ Done seq 20 | xargs -I{} echo -e 'sqlplus -s -l / as sysdba <<< @latch_free\nsleep 1' | bash >|/tmp/latch_freeo_${zdate}.txt
SYS@book> select addr,name,level#,latch#,gets,misses,sleeps,immediate_gets,immediate_misses,waiters_woken,waits_holding_latch,spin_gets,wait_time from v$latch_parent where lower(name) like '%'||lower('test excl. parent2 l0')||'%';
ADDR NAME LEVEL# LATCH# GETS MISSES SLEEPS IMMEDIATE_GETS IMMEDIATE_MISSES WAITERS_WOKEN WAITS_HOLDING_LATCH SPIN_GETS WAIT_TIME
---------------- --------------------- ------ ---------- ---------- ---------- ---------- -------------- ---------------- ------------- ------------------- ---------- ----------
0000000060009978 test excl. parent2 l0 0 5 5 0 0 7 5 0 0 0 0
--//可以发现gets增加1,IMMEDIATE_GETS增加1次,IMMEDIATE_MISSES增加1次.
--//我希望这个这个帖子对于理解latch的统计有所帮助.以前我对于这些统计参数的理解一片混乱.
--//大家可以适当调整sleep参数,测试看看各种情况.
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