Waits, Enqueues, and Latches - Expert Oracle RAC Performance Diagnostics and Tuning - page 576

gets / misses RATIO,
sleeps,
spin_gets,
immediate_gets Igets,
immediate_misses Imisses,
wait_time / 1000000 "WT"
FROM gv$latch
WHERE misses > 1000
ORDER BY inst_id,
spin_gets DESC;
The preceding V$LATCH output gives you details about misses and gets across various latches. To understand the
memory structure and for what memory address these latches are being requested, we query the V$LATCH_CHILDREN views.
Step 2
The task here is to determine the memory address that is consistently being missed and that has the highest miss rate.
Querying the view V$LATCH_CHILDREN can help us arrive at the address that has the highest miss rate.
Script: MVRACPDnTap_latchchildren.sql
SELECT inst_id INT,
latch#,
level#,
child# "Child",
addr "Address",
name "Name",
gets "Gets",
misses "Misses",
sleeps "Sleeps"
FROM gv$latch_children
WHERE misses > 1000
ORDER BY 1,
6,
2,
3;