Re: Informal poll: What's your avg redo write time?
- From: "Mladen Gogala" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "mgogala@xxxxxxxxx" for DMARC)
- To: oracle-l@xxxxxxxxxxxxx
- Date: Thu, 19 Feb 2015 17:28:29 -0500
On 02/19/2015 04:10 PM, Rich Jesse wrote:
Hey all,
In 11.2.0.3 on AIX 7.1, I'm tracing down an issue on an SR and
stumbled into the world of LGWR. It's causing blocking locks (falsely
being reported, I believe) when stressed, so I'm looking at LGWR
performance.
Using Kyle Hailey's average log write time query at the bottom of --
*NOTE: TUNING PACK LICENSE REQUIRED* --
http://www.oaktable.net/content/lgwr-redo-write-times-log-file-parallel-write
<javascript:void(0);/*1424380114607*/> my average is about 0.52ms with
90% of all between 0.4ms and 0.6ms, and another 8.4% at 0.7ms.
Knowing that there's over-committing going on, I'm thinking that
0.52ms isn't my issue, but what are other folks getting?
TIA!
Rich
p.s. Testing HTML formatting -- apologies if this message doesn't
look like it should!
Hi Rich,
I am now a consultant so I don't have the database that I am in charge
of and, consequently, no numbers for you. However, from the numbers you
presented, the duration of commit at this particular database is about
half a millisecond. That means that the database would theoretically be
able to commit 2000 times per second, which is not a shabby performance
by any standard. With all due respect, and we communicate by email on
and off this list for about two decades, you don't have a problem with
the duration of commit.
However I have recently encountered falsely reported blocking lock which
were happening whenever TEMP tablespace was being extended.
--
Mladen Gogala
Oracle DBA
http://mgogala.freehostia.com
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