Re: Informal poll: What's your avg redo write time?

From: Mladen Gogala <>
Date: Thu, 19 Feb 2015 17:28:29 -0500
Message-ID: <>

On 02/19/2015 04:10 PM, Rich Jesse wrote:
> Hey all,
> In 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 --
> <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

Received on Thu Feb 19 2015 - 23:28:29 CET

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