Sanjay,
Did you already look at this MoS note -2491760.1 ?
If this were to be applicable to your case, there is a patch and a workaround.
Regards,
Rajeev
On May 20, 2019 at 5:34 AM, <Stefan Koehler (mailto:contact@xxxxxxxx)>
wrote:
Hello Sanjay,
it seems like this is really an ASSM issue based on the stats of "ASSM gsp*"
and "ASSM cbk*".
Now it would be time to gather stack traces and check in more detail with the
already mentioned trace events 10320 and/or 10612.
You can also try to disable the ASSM rejection cache
(_enable_rejection_cache) or set event 10019 to level 1 but these would be
just some shot in the dark.
Best Regards
Stefan Koehler
Independent Oracle performance consultant and researcher
Website: http://www.soocs.de ;
Twitter: @OracleSK
Sanjay Mishra <smishra_97@xxxxxxxxx> hat am 18. Mai 2019 um 19:08--
geschrieben:
Stefan
Thanks for good document created by you to troubleshoot. Need to check as
what is best way to interpret snapper data but pasting the details and if
someone can provide any better guidance. Will also check more on Tanel site
for any demo to interpret the snapper report. As per Pages 20 and Explain
plan on Page 21 is exactly the same scenario.
Sampling SID 1070 with interval 1 seconds, taking 1 snapshots...
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
SID @INST, USERNAME , TYPE, STATISTIC , DELTA, HDELTA/SEC, %TIME, GRAPH ,
NUM_WAITS, WAITS/SEC, AVERAGES
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1070 @2, SYSADMIN, STAT, session logical reads , 13865, 7.73k, , , , ,
14.1k total buffer visits
1070 @2, SYSADMIN, STAT, user I/O wait time , 141, 78.65, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, non-idle wait time , 141, 78.65, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, non-idle wait count , 12230, 6.82k, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, physical read total IO requests , 6112, 3.41k, ,
, , , ~ per execution
1070 @2, SYSADMIN, STAT, physical read requests optimized , 6111, 3.41k, ,
, , , ~ per execution
1070 @2, SYSADMIN, STAT, physical read total bytes optimized , 50069504,
27.93M, , , , , ~ per execution
1070 @2, SYSADMIN, STAT, physical read total bytes , 50069504, 27.93M, , ,
, , ~ per execution
1070 @2, SYSADMIN, STAT, cell physical IO interconnect bytes , 50069504,
27.93M, , , , , ~ per execution
1070 @2, SYSADMIN, STAT, gcs messages sent , 3, 1.67, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, db block gets , 13860, 7.73k, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, db block gets from cache , 13860, 7.73k, , , , ,
~ per execution
1070 @2, SYSADMIN, STAT, db block gets from cache (fastpath) , 7737,
4.32k, , , , , ~ per execution
1070 @2, SYSADMIN, STAT, consistent gets , 1, .56, , , , , ~ per execution
1070 @2, SYSADMIN, STAT, consistent gets from cache , 1, .56, , , , , ~
per execution
1070 @2, SYSADMIN, STAT, consistent gets pin , 1, .56, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, consistent gets pin (fastpath) , 1, .56, , , , ,
~ per execution
1070 @2, SYSADMIN, STAT, logical read bytes from cache , 113541120,
63.34M, , , , , ~ per execution
1070 @2, SYSADMIN, STAT, physical reads , 6111, 3.41k, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, physical reads cache , 6111, 3.41k, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, physical read IO requests , 6112, 3.41k, , , , ,
8.19k bytes per request
1070 @2, SYSADMIN, STAT, physical read bytes , 50069504, 27.93M, , , , , ~
per execution
1070 @2, SYSADMIN, STAT, db block changes , 11, 6.14, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, free buffer requested , 6112, 3.41k, , , , , ~
per execution
1070 @2, SYSADMIN, STAT, hot buffers moved to head of LRU , 958, 534.39, ,
, , , ~ per execution
1070 @2, SYSADMIN, STAT, free buffer inspected , 6144, 3.43k, , , , , ~
per execution
1070 @2, SYSADMIN, STAT, shared hash latch upgrades - no wait , 7, 3.9, ,
, , , ~ per execution
1070 @2, SYSADMIN, STAT, blocks decrypted , 6110, 3.41k, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, redo entries , 6120, 3.41k, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, redo size , 465504, 259.67k, , , , , ~ bytes per
user commit
1070 @2, SYSADMIN, STAT, redo entries for lost write detection , 6110,
3.41k, , , , , ~ per execution
1070 @2, SYSADMIN, STAT, redo size for lost write detection , 464756,
259.25k, , , , , ~ per execution
1070 @2, SYSADMIN, STAT, redo subscn max counts , 7, 3.9, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, file io wait time , 1408659, 785.78k, , , , ,
230.47us bad guess of IO wait time per IO request
1070 @2, SYSADMIN, STAT, gc current blocks received , 3, 1.67, , , , , ~
per execution
1070 @2, SYSADMIN, STAT, gc local grants , 6116, 3.41k, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, ASSM cbk:blocks examined , 12366, 6.9k, , , , , ~
per execution
1070 @2, SYSADMIN, STAT, ASSM gsp:L1 bitmaps examined , 2478, 1.38k, , , ,
, ~ per execution
1070 @2, SYSADMIN, STAT, ASSM gsp:L2 bitmaps examined , 1, .56, , , , , ~
per execution
1070 @2, SYSADMIN, STAT, ASSM gsp:reject db , 12388, 6.91k, , , , , ~ per
execution
1070 @2, SYSADMIN, STAT, buffer is pinned count , 230, 128.3, , , , , 1.63
% buffer gets avoided thanks to buffer pin caching
1070 @2, SYSADMIN, STAT, cell flash cache read hits , 6723, 3.75k, , , , ,
~ per execution
1070 @2, SYSADMIN, TIME, background cpu time , 365192, 203.71ms, 20.4%,
[## ], , ,
1070 @2, SYSADMIN, TIME, background elapsed time , 1273623, 710.45ms,
71.0%, [######## ], , , 28.95 % unaccounted time
1070 @2, SYSADMIN, WAIT, gc current block busy , 629, 350.87us, .0%, [ ],
3, 1.67, 209.67us average wait
1070 @2, SYSADMIN, WAIT, cell single block physical read , 1557638,
868.88ms, 86.9%, [WWWWWWWWW ], 6746, 3.76k, 230.9us average wait
-- End of Stats snap 1, end=2019-05-18 12:58:58, seconds=1.8
//www.freelists.org/webpage/oracle-l ;
