Re: Do you use ASSM (Automatic Segment Space Management)?
From: kevin <majunyue_at_hotmail.com>
Date: Tue, 4 Aug 2009 17:30:03 -0700 (PDT)
Message-ID: <addf6fc8-111e-4cfb-89eb-a3fd4365ede3_at_y10g2000prg.googlegroups.com>
On Aug 4, 8:07 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: Tue, 4 Aug 2009 17:30:03 -0700 (PDT)
Message-ID: <addf6fc8-111e-4cfb-89eb-a3fd4365ede3_at_y10g2000prg.googlegroups.com>
On Aug 4, 8:07 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.
Our compnay's DBs all use ASSM. It's fine! we don't need rebuild indexes again. Received on Tue Aug 04 2009 - 19:30:03 CDT