Join IIUG
 for   
 

Informix News
18 Nov 13 - ZDNet - Top 20 mobile skills in demand... Read
09 Sep 13 - telecompaper - Shaspa and Tatung have shown a new smart home platform at Ifa in Berlin. Powered by the IBM Informix software... Read
06 Sep 13 - IBM data magazine - Mission Accomplished - Miami, Florida will be the backdrop for the 2014 IIUG Informix Conference... Read
01 Feb 13 - IBM Data Magazine - Are your database backups safe? Lester Knutsen (IBM Champion) writes about database back up safety using "archecker"... Read
14 Nov 12 - IBM - IBM's Big Data For Smart Grid Goes Live In Texas... Read
3 Oct 12 - The Financial - IBM and TransWorks Collaborate to Help Louisiana-Pacific Corporation Achieve Supply Chain Efficiency... Read
28 Aug 12 - techCLOUD9 - Splunk kicks up a SaaS Storm... Read
10 Aug 12 - businessCLOUD9 - Is this the other half of Cloud monitoring?... Read
3 Aug 12 - IBM data management - Supercharging the data warehouse while keeping costs down IBM Informix Warehouse Accelerator (IWA) delivers superior performance for in-memory analytics processing... Read
2 Aug 12 - channelbiz - Oninit Group launches Pay Per Pulse cloud-based service... Read
28 May 12 - Bloor - David Norfolk on the recent Informix benchmark "pretty impressive results"... Read
23 May 12 - DBTA - Informix Genero: A Way to Modernize Informix 4GL Applications... Read
9 Apr 12 - Mastering Data Management - Upping the Informix Ante: Advanced Data Tools... Read
22 Mar 12 - developerWorks - Optimizing Informix database access... Read
14 Mar 12 - BernieSpang.com - International Informix User Group set to meet in San Diego... Read
1 Mar 12 - IBM Data Management - IIUG Heads West for 2012 - Get ready for sun and sand in San Diego... Read
1 Mar 12 - IBM Data Management - Running Informix on Solid-State Drives.Speed Up Database Access... Read
26 Feb 12 - BernieSpan.com - Better results, lower cost for a broad set of new IBM clients and partners... Read
24 Feb 12 - developerWorks - Informix Warehouse Accelerator: Continuous Acceleration during Data Refresh... Read
6 Feb 12 - PRLOG - Informix port delivers unlimited database scalability for popular SaaS application ... Read
2 Feb 12 - developerWorks - Loading data with the IBM Informix TimeSeries Plug-in for Data Studio... Read
1 Feb 12 - developerWorks - 100 Tech Tips, #47: Log-in to Fix Central... Read
13 Jan 12 - MC Press online - Informix Dynamic Server Entices New Users with Free Production Edition ... Read
11 Jan 12 - Computerworld - Ecologic Analytics and Landis+Gyr -- Suitors Decide to Tie the Knot... Read
9 Jan 12 - planetIDS.com - DNS impact on Informix / Impacto do DNS no Informix... Read
8 Sep 11 - TMCnet.com - IBM Offers Database Solution to Enable Smart Meter Data Capture... Read
1 Aug 11 - IBM Data Management Magazine - IIUG user view: Happy 10th anniversary to IBM and Informix... Read
8 Jul 11 - Database Trends and Applications - Managing Time Series Data with Informix... Read
31 May 11 - Smart Grid - The meter data management pitfall utilities are overlooking... Read
27 May 11 - IBM Data Management Magazine - IIUG user view: Big data, big time ( Series data, warehouse acceleration, and 4GLs )... Read
16 May 11 - Business Wire - HiT Software Announces DBMoto for Enterprise Integration, Adds Informix. Log-based Change Data Capture... Read
21 Mar 11 - Yahoo! Finance - IBM and Cable&Wireless Worldwide Announce UK Smart Energy Cloud... Read
14 Mar 11 - MarketWatch - Fuzzy Logix and IBM Unveil In-Database Analytics for IBM Informix... Read
11 Mar 11 - InvestorPlace - It's Time to Give IBM Props: How many tech stocks are up 53% since the dot-com boom?... Read
9 Mar 11 - DBTA - Database Administration and the Goal of Diminishing Downtime... Read
2 Feb 11 - DBTAs - Informix 11.7 Flexible Grid Provides a Different Way of Looking at Database Servers... Read
27 Jan 11 - exactsolutions - Exact to Add Informix Support to Database Replay, SQL Monitoring Solutions... Read
25 Jan 11 - PR Newswire - Bank of China in the UK Works With IBM to Become a Smarter, Greener Bank... Read
12 Oct 10 - Database Trends and Applications - Informix 11.7: The Beginning of the Next Decade of IBM Informix... Read
20 Sep 10 - planetIDS.com - ITG analyst paper: Cost/Benefit case for IBM Informix as compared to Microsoft SQL Server... Read
20 Jul 10 - IBM Announcements - IBM Informix Choice Edition V11.50 helps deploy low-cost scalable and reliable solutions for Apple Macintosh and Microsoft Windows... Read
20 Jul 10 - IBM Announcements - Software withdrawal: Elite Support for Informix Ultimate-C Edition... Read
24 May 10 - eWeek Europe - IBM Supplies Database Tech For EU Smart Grid... Read
23 May 10 - SiliconIndia - IBM's smart metering system allows wise use of energy... Read
21 May 10 - CNET - IBM to help people monitor energy use... Read
20 May 10 - ebiz - IBM Teams With Hildebrand To Bring Smart Metering To Homes Across Britain... Read
19 May 10 - The New Blog Times - Misurare il consumo energetico: DEHEMS è pronto... Read
19 May 10 - ZDNet - IBM software in your home? Pact enables five-city smart meter pilot in Europe... Read
17 March 10 - ZDNet (blog) David Morgenstern - TCO: New research finds Macs in the enterprise easier, cheaper to manage than... Read
17 March 2010 - Virtualization Review - ...key components of Big Blue's platform to the commercial cloud such as its WebSphere suite of application ser vers and its DB2 and Informix databases... Read
10 February 2010 - The Wall Street Journal - International Business Machines is expanding an initiative to win over students and professors on its products. How do they lure the college crowd?... Read


End of Support Dates

IIUG on Facebook IIUG on Twitter

[ View Thread ] [ Post Response ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

IDS Forum

Re: Fw: Optimizer

Posted By: Peter_Logan@spartanstores.com
Date: Thursday, 29 March 2012, at 8:27 a.m.

In Response To: Re: Fw: Optimizer (Fernando Nunes)

Thanks for the reply ... Yes, the auto stats updating has been disabled
.. and I am aware of the external optimizer directives ...

Let me try to sum this up a little differently ... when the date was say
9/15/2011 .... one query plan was followed ... the one that works ... now
that the date is 3/28/2012 ... the optimizer is choosing a different path
.. so, what it seems to me is that the optimizer must be evaluating that
part of the query .. and then figuring out the query plan from there ... I
could understand that if this was a constant, but this isn't ... the
select weekid(today, -1) from systables where tabid = 1 is a procedure
that brings back the fiscal week id .. ie 201252 ... does that make a
little ore sense ... I'm trying to figure out if the optimizer is making
that evaluation .. then coming up with the plan.... and if so, how to keep
it from doing that ....

Peter Logan
Senior Database Administrator
Phone: 616/878-8309

From: "Fernando Nunes" <domusonline@gmail.com>
To: ids@iiug.org
Date: 03/28/2012 05:11 PM
Subject: Re: Fw: Optimizer [26592]
Sent by: ids-bounces@iiug.org

I'm afraid I didn't understand your point correctly. You mention the
select
from systables but I didn't understand how it's relevant for the problem.
Are you saying that query presented works fine but if you use the select
from systables instead of:

and a12.fiscal_week_id in (201253)

It will break the query plan?

In any case a few warnings and maybe some useful information:

- 11.7 alreay includes the AUTO_STAT_MODE parameter. This activates or
deactivates the optimization that says to the engine that "if the table
doesn't change too much don't bother to update it's statistics". I had a
recent situation where the default threshold was causing some stalled
statistics and it made a difference on the query plans. And the
probability
that this happens with queries involving time/dates is higher than with
other types of filters (because these fields many times tend to be
populated with constantly increasing values, so statistically something
that makes the filter "column > today - some_time" look good will in time
lead to bad choices)

- You can activate optimizer directives for any query outside the
applications by using the External Directives feature. I will not go into
details, because it could take a while, but if you're not aware of this
and
need further information, please tell. In any case I'm against the
principle of using directives to solve query plans problems... after all
we
have an optimizer... we're not Oracle :)

So, my advise:
- Verify that the distributions are really up to date (disable
AUTO_STAT_MODE) and run them (it's dynamic and I believe there's a way to
control it inside the session (either with SET ENVIRONMENT or with a
environment variable)
- If you never used the external optimizer directives, please investigate
them. Sometimes you can get away with them to quickly solve a performance
problem. But my advise is to always investigate this kind of problems and
find a definitive solution
- You could of course re-post your problem in a manner I can understand,
or
wait until someone smarter to answer you :)

Regards.

On Wed, Mar 28, 2012 at 9:00 PM, Peter_Logan@spartanstores.com <
Peter_Logan@spartanstores.com> wrote:

> Aix 6.1
> IDS 11.70.fc3
>
> The below query was executing ok, and then recently it started taking a
> lot longer... In looking at the query plans, the order of the tables
> changed a few weeks ago... Amount of data and stats in the tables
haven't
> changed dramatically ...
>
> The question I have, is ... Is the optimizer smart enough to execute the

> (select weekid(today, -1) from systables where tabid = 1 ... I can
> duplicate if I take that select out and hard code the fiscal week id ..
> runs about a minute .. then runs about 4 minutes. The query plan changes

> ... If I do run the query with the directive ... then I can consistently

> get it to run around a minute .. The problem is that this is a Micro
> Strategies report, so that optimizer directive can't be included ....
> Any help would be appreciated ...
>
> Peter Logan
> Senior Database Administrator
> Phone: 616/878-8309
> ----- Forwarded by Peter Logan/Corporate/Spartan on 03/28/2012 03:53 PM
> -----
>
> From: plisad0 (spartan02) <plisad0@spartanstores.com>
> To: Peter_Logan@spartanstores.com
> Date: 03/28/2012 03:52 PM
> Subject: Optimizer
>
> -- select --+ORDERED
> select
> a18.mdse_grp_key mdse_grp_key,
>
> a12.fiscal_week_id fiscal_week_id,
>
> a13.catgy_manager_key catgy_manager_key,
>
> (sum(a11.total_sales_amt) * 0.001) WJXBFS1,
>
> sum(a11.ext_profit_amt) WJXBFS2,
>
> sum(a11.total_sales_amt) WJXBFS3,
>
> sum(a11.ext_profit_amt) WJXBFS4
> from
>
> week_to_year_lkp a12,
>
> channel a16,
>
> chain a15,
>
> line a14,
> efin_wk_line_cls a11,
>
> mdse_class_manager a13,
>
> mdse_class a17,
>
> mdse_category a18,
>
> mdse_group a19,
>
> department a110,
>
> business_dept a111
> where a11.fiscal_week_id = a12.fiscal_wty_id and
>
> a11.mdse_class_key = a13.mdse_class_key and
>
> a11.sales_line_id = a14.sales_line_id and
>
> a14.sales_chain_id = a15.sales_chain_id and
>
> a15.sales_channel_id = a16.sales_channel_id and
>
> a11.mdse_class_key = a17.mdse_class_key and
>
> a17.mdse_catgy_key = a18.mdse_catgy_key and
>
> a18.mdse_grp_key = a19.mdse_grp_key and
>
> a19.dept_key = a110.dept_key and
>
> a110.bus_dept_key = a111.bus_dept_key
>
> and (a16.enterprise_id in (18)
>
> and a13.catgy_manager_key in (70)
>
> and a110.dept_grp_key not in (525, 9)
>
> and a14.format_type_id in ('SUPERMKT ')
>
> and a12.fiscal_week_id in (201253)
>
> and a111.dept_grp_type_key in (1))
> group by a18.mdse_grp_key,
>
> a12.fiscal_week_id,
>
> a13.catgy_manager_key
> into temp ZZMD03 with no log
>
>
>
>
*******************************************************************************

> Forum Note: Use "Reply" to post a response in the discussion forum.
>
>

--
Fernando Nunes
Portugal

http://informix-technology.blogspot.com
My email works... but I don't check it frequently...

--0023544710d08e6fef04bc540bf4

*******************************************************************************

Forum Note: Use "Reply" to post a response in the discussion forum.

Messages In This Thread

  • Fw: Optimizer
    Peter_Logan@spartanstores.com -- Wednesday, 28 March 2012, at 3:59 p.m.

[ View Thread ] [ Post Response ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

IDS Forum is maintained by Administrator with WebBBS 5.12.