Re: Do you use ASSM (Automatic Segment Space Management)?
From: Noons <wizofoz2k_at_gmail.com>
Date: Mon, 3 Aug 2009 21:54:28 -0700 (PDT)
Message-ID: <f6378e1e-007d-4a27-8d08-7b702a7cfe34_at_a39g2000pre.googlegroups.com>
On Aug 4, 10:07 am, ca111026 <ca111..._at_gmail.com> wrote:
> Do you use ASSM (Automatic Segment Space Management)?
> This feature was introduced in 9.2. The benefits are unclear - have
> anyone seen test results proving that in real-life situation ASSM
> produces improvements?
> At the same time ASSM has so many bugs: slow performance, spin/hang,
> excessive space usage, space leaks, etc. Just search Metalink for
> ASSM. Almost all ASSM-related bugs are "private", i.e. no additional
> information is available.
>
> For example:
>
> Bug 7575925 – ASSM blocks may be marked with wrong “freeness” (private
> bug)
> Affected version: 10.2.0.4
> Fixed in: 10.2.0.5, 11.2 (Future Release)
>
> Bug 5728380 – DML may spin searching for space in ASSM (private bug)
> Affected versions: 9.2.0.8, 10.2.0.3
>
> We had several instances where Apps Support would run large uncomitted
> DELETE (in different apps) and performance of single-row INSERT would
> deteriorate dramatically: from 10 buffer gets per INSERT to 100,000.
Date: Mon, 3 Aug 2009 21:54:28 -0700 (PDT)
Message-ID: <f6378e1e-007d-4a27-8d08-7b702a7cfe34_at_a39g2000pre.googlegroups.com>
On Aug 4, 10:07 am, ca111026 <ca111..._at_gmail.com> wrote:
> Do you use ASSM (Automatic Segment Space Management)?
> This feature was introduced in 9.2. The benefits are unclear - have
> anyone seen test results proving that in real-life situation ASSM
> produces improvements?
> At the same time ASSM has so many bugs: slow performance, spin/hang,
> excessive space usage, space leaks, etc. Just search Metalink for
> ASSM. Almost all ASSM-related bugs are "private", i.e. no additional
> information is available.
>
> For example:
>
> Bug 7575925 – ASSM blocks may be marked with wrong “freeness” (private
> bug)
> Affected version: 10.2.0.4
> Fixed in: 10.2.0.5, 11.2 (Future Release)
>
> Bug 5728380 – DML may spin searching for space in ASSM (private bug)
> Affected versions: 9.2.0.8, 10.2.0.3
>
> We had several instances where Apps Support would run large uncomitted
> DELETE (in different apps) and performance of single-row INSERT would
> deteriorate dramatically: from 10 buffer gets per INSERT to 100,000.
We use ASSM extensively.
And most of the bugs in 10.2.0.3 have patches and fixes. Which we have
installed: I reckon it's a better use of our time than the silly CPUs.
Received on Mon Aug 03 2009 - 23:54:28 CDT