Re: Database upgrade/move I/O waits performance

Hi,

how about the average I/O wait time in both AWR? How is the I/O wait histogram?
Get runtime stats from your queries. Did you license diagnostic and Tuning pack?
Did you disable adaptive features? Tried OFE 11.2.0.4? Why 12.1. which is known to have performance issues?

Regards

Lothar

Am 23.07.2019 um 18:39 schrieb Lyall Barbour:
> Hello gurus,
>   We've upgraded and moved the company's CRM OLTP Oracle database.
> Old: physical hardware, 512g RAM, 32 CPU -- Oracle 11.2.0.4
> Enterprise, 16g MEMORY_TARGET, SPM baselines used, one or two Profiles.
> New: VMWare VM, 224g RAM, 24 vCPU -- Oracle 12.1.0.2 Enterprise, 72g
> SGA_TARGET, HugePages, 12g PGA_TARGET, no SPM baselines, multiple
> Profiles.
> Having said all that, there's a consistency to the slowness that's
> very interesting.  We are constantly having I/O waits on all (?)
> queries, if not all, the main top sqls that are running in
> v$session_longops.
> Comparing one query.  Explain Plan, Cost, disk reads, buffer gets, all
> line up pretty well in 11g and 12c.  The 2 things that are different
> is the actual time, slowest in 11g is 2.5 seconds, 12c is 14 seconds. 
> and percentage of work, 11g disk work is 85% and cpu work is 15%.  12c
> disk work is 98%, cpu 2%.
> I'm not trying to get any solutions from everyone here, i'm trying to
> get direction on where to look next so i know who to talk to at my
> company with this issue.  Do i talk to the SAN folks and see what
> their graphs are like?  VM team?  keep digging into AWR stats and
> comparisons on the database?
> Comparing AWR hour periods from today (oracle 12.1) to last week,
> tuesday, (oracle 11.2) the amount of buffer gets and disk reads all
> line up with the issue i described above. 420T of buffer cache
> reads last week, 10T today, in that hour period.  ALL work is waiting
> on disk.
> Any help... helps.
> Thanks,
> Lyall Barbour
> -- http://www.freelists.org/webpage/oracle-l

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