[20190423]简单测试latch nowilling等待模式.txt

--//我对这个问题的理解就是如果参数willing=0,表示无法获取该latch，直接退出，再寻找类似的latch。
--//我仅仅知道redo copy latch具有这个特性：
> select addr,name,level#,latch#,gets,misses,sleeps,immediate_gets,immediate_misses,waiters_woken,waits_holding_latch,spin_gets,wait_time from v$latch_children where lower(name) like '%'||lower('redo copy')||'%' ;
ADDR             NAME       LEVEL#     LATCH#       GETS     MISSES     SLEEPS IMMEDIATE_GETS IMMEDIATE_MISSES WAITERS_WOKEN WAITS_HOLDING_LATCH  SPIN_GETS  WAIT_TIME
---------------- ---------- ------ ---------- ---------- ---------- ---------- -------------- ---------------- ------------- ------------------- ---------- ----------
00000012D720ADA8 redo copy       4        208         53          0          0      500627938           304381             0                   0          0          0
00000012D720ACD0 redo copy       4        208         53          0          0      497827706           323330             0                   0          0          0
..
00000012D72086D8 redo copy       4        208         53          0          0      491448415           365472             0                   0          0          0
00000012D7208600 redo copy       4        208         53