Yes, index and table blocks. No DDL for quite a while and no large DML that
I’ve been able to uncover.
No memory pool resizing since January 9, 2019.
Sr. Oracle DBA
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Sayan Malakshinov
Sent: Thursday, March 14, 2019 6:06 PM
Subject: Re: Keep buffer cache question
Have you checked what is it reading? Index blocks, table blocks or undo? Were
there any DDL or huge DML operations? Have you checked v$bh? What about memory
settings? AMM/ASMM/manual? Have you checked v$sga_resize_ops?
On Fri, Mar 15, 2019 at 12:22 AM Redacted sender Jay.Miller for DMARC
Odd issue here. One of our apps reported slightly increased latency on a
heavily used database which started Monday evening and has been consistent
since. This is not large from a database perspective but the increase of
average response time from 1 to 3 microseconds has had a noticeable impact on
No execution plan changes, a slightly heavier load at peak times (up about 10%
from last week) but nothing that I would expect to have such an impact. We
still see the increased latency when the server is 90% idle and the load
average is 5 (32 cpus, 16 cores).
In doing an AWR report comparison for comparable times one major difference I
saw was that 2 frequently run queries were suddenly doing a lot of physical
i/o. For a comparable 2 hour period they went from 1.5 million to 1.8 million
executions but physical reads increased from 0 to 1.2 million. I sampled a few
other random times and this was consistent. The queries are both doing index
access. One is an index range scan and the other a unique scan against the
I checked with the app group and they have no explanation for why the app might
suddenly be querying blocks that aren't in cache whereas they weren't last week.
Sr. Oracle DBA
Oracle performance tuning engineer
Oracle ACE Associate