What is your backup target? Source media? Third-party backup application?
We had a problem with backing up to Oracle Cloud after moving to 19.15 and
the solution turned out to be re-installing the Oracle Database Cloud
Backup Module . Seems there is a mismatch with the older oci interface. I
wouldn't bet against a similar issue with the libraries in 19.14.
On Tue, Aug 16, 2022 at 10:38 AM Mladen Gogala <gogala.mladen@xxxxxxxxx>
wrote:
On 8/16/22 09:44, Beckstrom, Jeffrey wrote:
In a rare factual error my friend Mladen missed that the list is ascending.
Still probably a network issue. Smirk. Unless that is backup & recovery
read time (The key thing that **might** tell you a **lot** would be
separation of I/O into I and O). I cannot remember their detailed
description of this event and I’m too lazy to too it up. But I did
re-arrange the output for that one line into “What” and useful “How much”
columns.
Notice that the “also ran” second place was only about a minute of total
wait. So this one bundled line for I and O is pretty much everything. So 41
milliseconds per I/O and I have no idea what a raw system level I/O between
your source system and backup system is, or what size RMAN’s I/O unit is
(min, max, average) as configured. If you have some idea of the total bytes
written, you could do a system to system level I/O of that size (maybe a
bundle of 100 or 1000 repeats, so any possible begin and end process time
error is minimized) and get a clue whether I/O time between systems is the
problem, rather than something more complex inside Oracle.
Of course, Mark is right. I am using similar kind of query with "DESC"
option for the ordering so I assumed that Jeff does the same. Apparently,
my assupmtion was wrong. Not only that, rman network communication doesn't
use SQL*Net, so the "SQL Net data to client" message is unlikely to be
caused by rman. It *might*, however, be indicative of a network problem.
My advice would be to also check disk I/O and network throughput using the
Linux tools like atop, iotop and iptraf-ng. Even strace can be useful in
this situation. Also useful are "perf" tools, like "perf top" and system
wide profilers like "oprofile".
You may need to open a case with Oracle or your backup vendor.
Regards
--
Mladen Gogala
Database Consultant
Tel: (347) 321-1217https://dbwhisperer.wordpress.com
