Tuning query performance

Dear experts,
I have a question regarding as the performance of a BW query.
It takes 10 minutes to display about 23 thousands lines.
This query read the data from an ODS object.
According to the "where" clause in the "select" statement monitored via Oracle session when the query was running, I created an index for this ODS object.
After rerunning the query, I found that the index had been taken by Oracle in reading this table (estimated cost is reduced to 2 from about 3000).
However, it takes the same time as before.
Is there any other reason or other factors that I should consider in tuning the performance of this query?K
Thanks in advance

Hi David,
Query performance when reporting on ODS object is slower compared to infocubes, infosets, multiproviders etc because of no aggregates and other performance techinques in DSO.
Basically for DSO/ODS you need to turn on the BEx reporting flag, which again is an overhead for query execution and affects performance.
To improve the performance when reporting on ODS you can create secondary indexes from BW workbench.
Please check the below links.
[Re: performance issues of ODS]
[Which criteria to follow to pick InfoObj. as secondary index of ODS?;
Hope this helps.
Regards,
Haritha.

Similar Messages

Query Performance Issues on a cube sized 64GB.

Hi,
We have a non-time based cube whose size is 64 GB . Effectively, I can't use time dimension for partitioning. The transaction table has ~ 850 million records. We have 20+ dimensions among which 2 of the dimensions have 50 million records.
I have equally distributed the fact table records among 60 partitions. Each partition size is around 900 MB.
The processing of the cube is not an issue as it completes in 3.5 hours. The issue is with the query performance of the cube.
When an MDX query is submitted, unfortunately, in majority of the cases the storage engine has to scan all the partitions (as our cube is not time dependent and we can't find a suitable dimension that will fit the bill to partition measure group based
on it.)
I'm aware of the cache warming and usage based aggregation(UBO) techniques.
However, the cube is available for users to perform adhoc queries and hence the benefits of cache warming and UBO may cease to contribute to the performance gain as there is a high probability that each user may look at the data from different perspectives
(especially when we have 20 + dimensions) as day(s) progress.
Also, we have 15 + average calculations (calculated measures) in the cube. So, the storage engine sends all the granular data that the formula engine might have requested (could be millions of rows) and then perform the average calculation.
A look at the profiler suggested that considerable amount of time has been spent by storage engine to gather the records (from 60 partitions).
FYI - Our server has RAM 32 GB and 8 cores and it is exclusive to Analysis Services.
I would appreciate comments from anyone who has worked on a large cube that is not time dependent and the steps they took to improve the adhoc query performance for the users.
Thanks
CoolP

Hello CoolP,
Here is a good articles regarding how to tuning query performance in SSAS, please see:
Analysis Services Query Performance Top 10 Best Practices:
http://technet.microsoft.com/en-us/library/cc966527.aspx
Hope you can find some helpful clues to tuning your SSAS Server query performance. Moreover, there are two ways to improve the query response time for an increasing number of end-users:
Adding more power to the existing server (scale up)
Distributing the load among several small servers (scale out)
For detail information, please see:
http://technet.microsoft.com/en-us/library/cc966449.aspx
Regards,
Elvis Long
TechNet Community Support

Tuning SAP BW query performance

Dear experts,
I have a question regarding as the performance of a BW query.
It takes 10 minutes to display about 23 thousands lines.
This query read the data from an ODS object.
According to the "where" clause in the "select" statement monitored via Oracle session when the query was running, I created an index for this ODS object.
After rerunning the query, I found that the index had been taken by Oracle in reading this table (estimated cost is reduced to 2 from about 3000).
However, it takes the same time as before.
Is there any other reason or other factors that I should consider in tuning the performance of this query?K
Thanks in advance

check out tuning documents at [FAQ - The Future of SAP NetWeaver Business Intelligence in the Light of the NetWeaver BI&Business Objects Roadmap]

Performance Tuning : Query session

Dear Friends,
I am working with Hyperion Interactive reporting and I am very new to this environment, I am having a query session with 11 tables all are simple joins. when ever I am processing the query it talks long time to fetch the data ofcourse it has milions of records, do you have any idea how do I reduce query processing time. or else please tell me what are things I need to do and what are things I need not do. any query performance tips in brio.
Best Regards,
S.Murugan

Query Performance is based on a variety of factors.
- Network speed
- size of dataset returning -- Are you really bringing back 1 million rows?
- properly tuned database -- Capture the SQL and have DBA review it
- proper created query - correct order of tables for the FROM clause -- This is based on order they were brought into the data model section
Wayne Van Sluys
TopDown Consulting

Reg: Process Chain, query performance tuning steps

Hi All,
I come across a question like, There is a process chain of 20 processes.out of which 5 processes are completed at the 6th step error occured and it cannot be rectified. I should start the chain again from the 7th step.If i go to a prticular step i can do that particular step, How can i start the entair chain again from step 7.i know that i need to use a function module but i dont know the name of FM. Please somebody help me out.
Please let me know the steps involved in query performance tuning and aggregate tuning.
Thanks & Regards
Omkar.K

Hi,
Process Chain
Method 1 (when it fails in a step/request)
/people/siegfried.szameitat/blog/2006/02/26/restarting-processchains
How is it possible to restart a process chain at a failed step/request?
Sometimes, it doesn't help to just set a request to green status in order to run the process chain from that step on to the end.
You need to set the failed request/step to green in the database as well as you need to raise the event that will force the process chain to run to the end from the next request/step on.
Therefore you need to open the messages of a failed step by right clicking on it and selecting 'display messages'.
In the opened popup click on the tab 'Chain'.
In a parallel session goto transaction se16 for table rspcprocesslog and display the entries with the following selections:
1. copy the variant from the popup to the variante of table rspcprocesslog
2. copy the instance from the popup to the instance of table rspcprocesslog
3. copy the start date from the popup to the batchdate of table rspcprocesslog
Press F8 to display the entries of table rspcprocesslog.
Now open another session and goto transaction se37. Enter RSPC_PROCESS_FINISH as the name of the function module and run the fm in test mode.
Now copy the entries of table rspcprocesslog to the input parameters of the function module like described as follows:
1. rspcprocesslog-log_id -> i_logid
2. rspcprocesslog-type -> i_type
3. rspcprocesslog-variante -> i_variant
4. rspcprocesslog-instance -> i_instance
5. enter 'G' for parameter i_state (sets the status to green).
Now press F8 to run the fm.
Now the actual process will be set to green and the following process in the chain will be started and the chain can run to the end.
Of course you can also set the state of a specific step in the chain to any other possible value like 'R' = ended with errors, 'F' = finished, 'X' = cancelled ....
Check out the value help on field rspcprocesslog-state in transaction se16 for the possible values.
Query performance tuning
General tips
Using aggregates and compression.
Using less and complex cell definitions if possible.
1. Avoid using too many nav. attr
2. Avoid RKF and CKF
3. Many chars in row.
By using T-codes ST03 or ST03N
Go to transaction ST03 > switch to expert mode > from left side menu > and there in system load history and distribution for a particual day > check query execution time.
/people/andreas.vogel/blog/2007/04/08/statistical-records-part-4-how-to-read-st03n-datasets-from-db-in-nw2004
/people/andreas.vogel/blog/2007/03/16/how-to-read-st03n-datasets-from-db
Try table rsddstats to get the statistics
Using cache memoery will decrease the loading time of the report.
Run reporting agent at night and sending results to email.This will ensure use of OLAP cache. So later report execution will retrieve the result faster from the OLAP cache.
Also try
1. Use different parameters in ST03 to see the two important parameters aggregation ratio and records transferred to F/E to DB selected.
2. Use the program SAP_INFOCUBE_DESIGNS (Performance of BW infocubes) to see the aggregation ratio for the cube. If the cube does not appear in the list of this report, try to run RSRV checks on the cube and aggregates.
Go to SE38 > Run the program SAP_INFOCUBE_DESIGNS
It will shown dimension Vs Fact tables Size in percent.If you mean speed of queries on a cube as performance metric of cube,measure query runtime.
3. --- sign is the valuation of the aggregate. You can say -3 is the valuation of the aggregate design and usage. ++ means that its compression is good and access is also more (in effect, performance is good). If you check its compression ratio, it must be good. -- means the compression ratio is not so good and access is also not so good (performance is not so good).The more is the positives...more is useful the aggregate and more it satisfies the number of queries. The greater the number of minus signs, the worse the evaluation of the aggregate. The larger the number of plus signs, the better the evaluation of the aggregate.
if "-----" then it means it just an overhead. Aggregate can potentially be deleted and "+++++" means Aggregate is potentially very useful.
Refer.
http://help.sap.com/saphelp_nw70/helpdata/en/b8/23813b310c4a0ee10000000a114084/content.htm
http://help.sap.com/saphelp_nw70/helpdata/en/60/f0fb411e255f24e10000000a1550b0/frameset.htm
4. Run your query in RSRT and run the query in the debug mode. Select "Display Aggregates Found" and "Do not use cache" in the debug mode. This will tell you if it hit any aggregates while running. If it does not show any aggregates, you might want to redesign your aggregates for the query.
Also your query performance can depend upon criteria and since you have given selection only on one infoprovider...just check if you are selecting huge amount of data in the report
Check for the query read mode in RSRT.(whether its A,X or H)..advisable read mode is X.
5. In BI 7 statistics need to be activated for ST03 and BI admin cockpit to work.
By implementing BW Statistics Business Content - you need to install, feed data and through ready made reports which for analysis.
http://help.sap.com/saphelp_nw70/helpdata/en/26/4bc0417951d117e10000000a155106/frameset.htm
/people/vikash.agrawal/blog/2006/04/17/query-performance-150-is-aggregates-the-way-out-for-me
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/1955ba90-0201-0010-d3aa-8b2a4ef6bbb2
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/ce7fb368-0601-0010-64ba-fadc985a1f94
http://help.sap.com/saphelp_nw04/helpdata/en/c1/0dbf65e04311d286d6006008b32e84/frameset.htm
You can go to T-Code DB20 which gives you all the performance related information like
Partitions
Databases
Schemas
Buffer Pools
Tablespaces etc
use tool RSDDK_CHECK_AGGREGATE in se38 to check for the corrupt aggregates
If aggregates contain incorrect data, you must regenerate them.
Note 646402 - Programs for checking aggregates (as of BW 3.0B SP15)
Thanks,
JituK

Oracle query performance tuning

Hi
I am doing Oracle programming.Iwould like to learn Query Performance Tuning.
Could you guide me , like how could i learn this online, which books to refer.
Thank you

I would recommend purchasing a copy of Cary Millsap's book now:
http://www.amazon.com/Optimizing-Oracle-Performance-Cary-Millsap/dp/059600527X/ref=sr_1_1?ie=UTF8&qid=1248985270&sr=8-1
And Jonathan Lewis' when you feel you are at a slightly more advanced level.
http://www.amazon.com/Cost-Based-Oracle-Fundamentals-Experts-Voice/dp/1590596366/ref=pd_sim_b_2
Both belong in everyone's bookcase.

Query Performance Issues

Hi Gurus,
I m woking on performance tuning at the moment and wants some tips
regarding the Query performance tuning,if anyone can helpme in that
rfrence.
the thing is that i have got an idea about the system and now the
issues r with DB space, Abap Dumps, problem in free space in table
space, no number range buffering,cubes r using too many aggrigates,
large IC,Large ODS, and many others.
So my questionis that is anyone can tell me that how to resolve the
issues with the Large master data tables,and large ODS,and one more
importnat issue is KPI´s exceding there refrence valuses so any idea
how to deal with them.
waiting for the valuable responces.
thanks In advance
Redards
Amit

Hi Amit
For Query performance issue u can go for :-
Aggregates : They will help u a lot to make ur query faster becuase query doesnt hits ur cube it hits the aggregates which has very less number of records in comp to ur cube
secondly i wud suggest u is use CKF in place of formulaes if any in the query
other thing is avoid upto the extent possible the use fo nav attr . if u want to use them use it upto the minimal level reason i am saying so is during the query exec whn ever there is nav attr it provides unncessary join to ur MD and thus dec query perfo
be specifc to rows and columns if u r not sure of a kf or a char then better put it in a free char.
use filters if possible
if u follow these m sure ur query perfo will inc
Assign points if applicable
Thanks
puneet

Bad Query Performance

Hi Experts,
I have a Query which was built on a multiprovider,Which has a slow preformance.
I think the main problem comes from selecting to many records from
I think it selects 1,1 million rows to display about 500 rows in the result.
Another point could be that the complicated restricted and calculated keyfigures, especially might spend a lot of time in the OLAP processor.
Here are the Statistics of the Query.
OLAP Initialization      : 3,186906
Wait Time, User         :   56,971169
OLAP: Settings               0,983193
Read Cache                     0,015642
Delete Cache                   0,019030
Write Cache                    0,087655
Data Manager                   462,039167
OLAP: Data Selection      0,671566
OLAP: Data Transfer       1,257884.
ST03 Stat:
%OLAP       :22,74
%DB           :77,18
OLAP Time :29,2
DBTime        :99,1
It seems that the maximum time is consuming in the Database
Any suggestion to speed up this Query response time would be great.
Thanks in advance.
BR
Srini.

Hi,
You need to have standard Query performance tuning done for the underlying cubes like better design, aggregates, etc
Improve Performance of Queries/Reports on Multi Cubes
Refer SAP Note Number: 869487
Performance optimization for MultiCubes
How to Create Efficient Multi-Provider Queries
Please see the How to Guide "How to Create Efficient MultiProvider Queries" at http://service.sap.com/bi > SAP NetWeaver 2004 - Release-Specific Information > How-to Guides > Business Intelligence
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/com.sap.km.cm.docs/library/biw/how%20to%20create%20efficient%20multiprovider%20queries.pdf
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/3f66ba90-0201-0010-ac8d-b61d8fd9abe9
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/afbad390-0201-0010-daa4-9ef0168d41b6
Performance of MultiProviders
Multiprovider performance / aggregate question
Query Performance
Multicube performances
Create Efficient MultiProvider Queries
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/b03b7f4c-c270-2910-a8b8-91e0f6d77096
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/751be690-0201-0010-5e80-f4f92fb4e4ab
Also try
Achieving BI Query Performance Building Business Intelligence
http://www.dmreview.com/issues/20051001/1038109-1.html
tuning, short dumps
Performance tuning in BW:
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/afbad390-0201-0010-daa4-9ef0168d41b6
Also notes
0000903559 MultiProvider optimization is only partially active
0000825396 Performance in reports with many selections
multiprovider explanation i need
Note 629541 - Multiprovider: Parallel Processing
Thanks,
JituK

Forms - Query - Performance

Hi,
I am working on a application Developed in Forms10g and Oralce 10g.
I have few very large transaction tables in db and most of the screens in my application based on these tables only.
When user performs a query (with out any filter conditions) the whole table(s) loaded into memory and takes very long time. Further queries on the same screen perform better.
How can I keep these tables in memory (buffer) always to reduce the initial query time?
or
Is there any way to share the session buffers with other sessions, sothat it does not take long time in each session?
or
Any query performance tuning suggestions will be appreciated.
Thanks in advance

Thanks a lot for your posts, very large means around
12 million rows. Yep, that's a large table
I have set the query all records to "No". Which is good. It means only enough records are fetched to fill the initial block. That's probably about 10 records. All the other records are not fetched from the database, so they're also not kept in memory at the Forms server.
Even when I try the query in SQL PLUS it is taking
long time. Sounds like a query performance problem, not a Forms issue. You're probably better of asking in the database or SQL forum. You could at least include the SELECT statement here if you want any help with it. We can't guess why a query is slow if we have no idea what the query is.
My concern is, when I execute the same query again or
in another session (some other user or same user),
can I increase the performance because the tables are
already in memory. any possibility for this? Can I
set any database parameters to share the data between
sessions like that... The database already does this. If data is retrieved from disk for one user it is cached in the SGA (Shared Global Area). Mind the word Shared. This caching information is shared by all sessions, so other users should benefit from it.
Caching also has its limits. The most obvious one is the size of the SGA of the database server. If the table is 200 megabyte and the server only has 8 megabyte of cache available, than caching is of little use.
Am I thinking in the right way? or I lost some where?Don't know.
There's two approaches:
- try to tune the query or database to have better performance. For starters, open SQL*Plus, execute "set timing on", then execute "set autotrace traceonly explain statistics", then execute your query and look at the results. it should give you an idea on how the database is executing the query and what improvements could be made. You could come back here with the SELECT statement and timing and trace results, but the database or SQL forum is probably better
- MORE IMPORTANTLY: think if it is necessary for users to perform such time consuming (and perhaps complex) queries. Do users really need the ability to query all records. Are they ever going to browse through millions of records?
>
>
Thanks

How to improve query performance using infoset

I create one infoset that including 4 char.and 3 DSO which all are time-dependent.When query run, system show very poor perfomance, sometimes no data show in BEX anayzer. In this case I have to close BEX analyzer at first and then open it again, after that it show real results. It seems very strange. Does anybody has experience on infoset performance improvement. pls info, thanks!

Hi
As info set itself doesn't have any data so it improves Performance
also go through the below tips.
Find the query Run-time
where to find the query Run-time ?
557870 'FAQ BW Query Performance'
130696 - Performance trace in BW
This info may be helpful.
General tips
Using aggregates and compression.
Using less and complex cell definitions if possible.
1. Avoid using too many nav. attr
2. Avoid RKF and CKF
3. Many chars in row.
By using T-codes ST03 or ST03N
Go to transaction ST03 > switch to expert mode > from left side menu > and there in system load history and distribution for a particular day > check query execution time.
Statistical Records Part 4: How to read ST03N datasets from DB in NW2004
How to read ST03N datasets from DB
Try table rsddstats to get the statistics
Using cache memory will decrease the loading time of the report.
Run reporting agent at night and sending results to email. This will ensure use of OLAP cache. So later report execution will retrieve the result faster from the OLAP cache.
Also try
1. Use different parameters in ST03 to see the two important parameters aggregation ratio and records transferred to F/E to DB selected.
2. Use the program SAP_INFOCUBE_DESIGNS (Performance of BW infocubes) to see the aggregation ratio for the cube. If the cube does not appear in the list of this report, try to run RSRV checks on the cube and aggregates.
Go to SE38 > Run the program SAP_INFOCUBE_DESIGNS
It will shown dimension Vs Fact tables Size in percent.If you mean speed of queries on a cube as performance metric of cube,measure query runtime.
3. To check the performance of the aggregates,see the columns valuation and usage in aggregates.
Open the Aggregates...and observe VALUATION and USAGE columns.
"---" sign is the valuation of the aggregate. You can say -3 is the valuation of the aggregate design and usage. ++ means that its compression is good and access is also more (in effect, performance is good). If you check its compression ratio, it must be good. -- means the compression ratio is not so good and access is also not so good (performance is not so good).The more is the positives...more is useful the aggregate and more it satisfies the number of queries. The greater the number of minus signs, the worse the evaluation of the aggregate. The larger the number of plus signs, the better the evaluation of the aggregate.
if "-----" then it means it just an overhead. Aggregate can potentially be deleted and "+++++" means Aggregate is potentially very useful.
In valuation column,if there are more positive sign it means that the aggregate performance is good and it is useful to have this aggregate.But if it has more negative sign it means we need not better use that aggregate.
In usage column,we will come to know how far the aggregate has been used in query.
Thus we can check the performance of the aggregate.
Refer.
http://help.sap.com/saphelp_nw70/helpdata/en/b8/23813b310c4a0ee10000000a114084/content.htm
http://help.sap.com/saphelp_nw70/helpdata/en/60/f0fb411e255f24e10000000a1550b0/frameset.htm
performance ISSUE related to AGGREGATE
Note 356732 - Performance Tuning for Queries with Aggregates
Note 166433 - Options for finding aggregates (find optimal aggregates for an InfoCube)
4. Run your query in RSRT and run the query in the debug mode. Select "Display Aggregates Found" and "Do not use cache" in the debug mode. This will tell you if it hit any aggregates while running. If it does not show any aggregates, you might want to redesign your aggregates for the query.
Also your query performance can depend upon criteria and since you have given selection only on one infoprovider...just check if you are selecting huge amount of data in the report
Check for the query read mode in RSRT.(whether its A,X or H)..advisable read mode is X.
5. In BI 7 statistics need to be activated for ST03 and BI admin cockpit to work.
By implementing BW Statistics Business Content - you need to install, feed data and through ready made reports which for analysis.
http://help.sap.com/saphelp_nw70/helpdata/en/26/4bc0417951d117e10000000a155106/frameset.htm
/people/vikash.agrawal/blog/2006/04/17/query-performance-150-is-aggregates-the-way-out-for-me
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/1955ba90-0201-0010-d3aa-8b2a4ef6bbb2
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/ce7fb368-0601-0010-64ba-fadc985a1f94
http://help.sap.com/saphelp_nw04/helpdata/en/c1/0dbf65e04311d286d6006008b32e84/frameset.htm
You can go to T-Code DB20 which gives you all the performance related information like
Partitions
Databases
Schemas
Buffer Pools
Tablespaces etc
use tool RSDDK_CHECK_AGGREGATE in se38 to check for the corrupt aggregates
If aggregates contain incorrect data, you must regenerate them.
202469 - Using aggregate check tool
Note 646402 - Programs for checking aggregates (as of BW 3.0B SP15)
You can find out whether an aggregate is usefull or useless you can find out through a proccess of checking the tables RSDDSTATAGGRDEF*
Run the query in RSRT with statistics execute and come back you will get STATUID... copy this and check in the table...
This gives you exactly which infoobjects it's hitting, if any one of the object is missing it's useless aggregate.
6
Check SE11 > table RSDDAGGRDIR . You can find the last callup in the table.
Generate Report in RSRT
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/cccad390-0201-0010-5093-fd9ec8157802
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/4c0ab590-0201-0010-bd9a-8332d8b4f09c
Business Intelligence Journal Improving Query Performance in Data Warehouses
http://www.tdwi.org/Publications/BIJournal/display.aspx?ID=7891
Achieving BI Query Performance Building Business Intelligence
http://www.dmreview.com/issues/20051001/1038109-1.html
Assign points if useful
Cheers
SM

Query performed well in dev but hanging on prod

Hi DBAs,
Urgent help is required on this issue.
One of my sql query performed well in dev server, but now for 1 week it is hanging in prod server so,
* How can i proceed to troubleshoot the problem.
* What are areas i need to look for , and for what ?
Regards
Asif

Are they both the same version of databases?
How recent is your dev data (if possible update your dev from prod)?
If prod to dev copy is not possible
....AND stats for both db are up-to-date
....AND big differnce in db size for dev & prod
....=> You can copy prod's stats and import to dev then run your query on dev to localise the issue then you can start tuning the query on dev.

Poor query performance in Prod.

I am facing lots of issues in my queries.
The query is working fine in Dev. but after i transported it to Prod. the query is taking too much time to retreive the result.
Why i am facing this issue.
How can i do the performance tuning for the query.?
The query is built on multiprovider and it is also jumping to the ODS for ODS query.
But the query performance is really low and poor in Production.
And to surprise the query is wroking perfectly and faster in Dev.
What can be the suggestion.
Please send documents for performnace tuning, notes number... etc.

Are datavolumes huge in Prod Box...dat may be cause 4 d slow runtimes.
<b>Look at below performance improving techs</b>
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/cbd2d390-0201-0010-8eab-a8a9269a23c2
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/aec09790-0201-0010-8eb9-e82df5763455
Business Intelligence Performance Tuning [original link is broken]
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/cccad390-0201-0010-5093-fd9ec8157802
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/ce7fb368-0601-0010-64ba-fadc985a1f94
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/c8c4d794-0501-0010-a693-918a17e663cc
Note 565725 - Optimizing the performance of ODS objects

Query performance on RAC is a lot slower than single instance

I simply followed the steps provided by oracle to install a rac db of 2 nodes.
The performce on Insertion (java, thin ojdbc) is pretty much the same compared to a single instance on NFS
However the performance on the select query is very slow compared to single instance.
I have tried using different methods for the storage configuration (asm with raw, ocfs2) but the performance is still slow.
When I shut down one instance, leaving only one instance up, the query performance is very fast (as fast as one single instance)
I am using rhel5 64 bit (16G of physical memory) and oracle 11.1.0.6 with patchset 11.1.0.7
Could someone help me how to debug this problem?
Thanks,
Chau
Edited by: user638637 on Aug 6, 2009 8:31 AM

top 5 timed foreground events:
DB CPU: times 943(s), %db time (47.5%)
cursor.pin S wait on X: wait(13940), time (321s), avg wait(23ms), %db time (16.15%)
direct path read (95,436), times (288), avg watie (3ms), %db ime (14.51%)
IPC send completion sync: wait(546,712), times(149s), avg wait (0), %db time (7.49%)
gc cr multi block request: waits (7574), teims (78) avg wait (10 ms), %db time (4.0)
another thing i see is the "avg global cache cr block flush time (ms): is 37.6 msThe DB CPU Oracle metric is the amount of CPU time (in microseconds) spent on database user-level calls.
You should check your sql statement from report and tuning them.
- Check from Execute Plan.
- If not index, determine to use index.
SQL> set autot trace explain
SQL> sql statement;
cursor: pin S wait on X.
A session waits on this event when requesting a mutex for sharable operationsrelated to pins (such as executing a cursor), but the mutex cannot be granted becauseit is being held exclusively by another session (which is most likely parsing the cursor).
use variable SQL , avoid dynamic sql
http://blog.tanelpoder.com/2008/08/03/library-cache-latches-gone-in-oracle-11g/
check about memory MEMORY_TARGET initialization parameter.
By the way you have high "DB CPU"(47.5%), you should tune about your sql statement (check sql in report and tune)
Good Luck

Improve the query performance

Hi, I need help for improving query performance..
I have a query in which i am joining 2 tables, join after some aggregation. Both table has more than 50 million record.
There is no index created on these table,both tables are loaded after truncation. So is it required to create index on this table before joining? The query status was showing 'suspended' since it was running for long time. For temporary purpose, i just executed
the query multiple times by changing month filter each times.
How can i improve this instead of adding month filter and running multiple times

Hi Nikkred,
According to your description, you are joining 2 table which contain more than 50 million records. Now what you want is improving query performance, right?
Query tuning is not an easy task. Basically it depends on three factors: your degree of knowledge, the query itself and the amount of optimization required. So in your scenario, you can post your detail query, so that you can get more help. Besides, you
can create index on your table which can improve the performance. Here are some links about performance tuning tips for you reference.
http://www.mssqltips.com/sql-server-tip-category/9/performance-tuning/
http://www.infoworld.com/d/data-management/7-performance-tips-faster-sql-queries-262
Regards,
Charlie Liao
TechNet Community Support

Query performance to increase

hi i'm using cte's as defined and took a temp table to take the columns from temp table.now,when i'm executing this logic of sp..its taking 7min for 3lakhs records. can any one pls help me how to improve my query performance..
the code which i'm using is:
create temtable as(cols);WITH Datematrix(AllocationDate)/*cte*/
As
SELECT @StartDate AS AllocationDate
UNION ALL
SELECT DATEADD(D,1,AllocationDate) AS AllocationDate
FROM Datematrix WHERE AllocationDate<@EndDate
/*cte*/ Allocation (Division,DivisionID,ResourceName,ResourceEmailID,ResourceID,Project
,ProjectID,Scope,ScopeID,WorkItem,TaskStartDate,TaskEndDate
,ProgramID ,Program,PortfolioID ,Portfolio,StatusID,Status,TaskID,EstimateHrs,ScopeEstimateHrs)
AS
SELECT
DIV.Division
,RES.DivisionID
,RES.ResourceName
,ResourceEmailID = STUFF((
SELECT COALESCE( ', ' + CONVERT(VARCHAR,RES.Email1), '')
FROM dbo.TasksResource TSKRES WITH(NOLOCK) LEFT OUTER JOIN
dbo.tb_Resource RES WITH(NOLOCK) ON RES.UID = TSKRES.ResourceID
WHERE TSKRES.TaskID = TSK.TaskID
FOR XML PATH('')), 1, 1, '')
,RES.UID ResourceID
,PRJ.Project + ' (' + CONVERT(VARCHAR(15),PRJ.StartDate,101) +' - ' + CONVERT(VARCHAR(15),PRJ.EndDate,101) + ')' as Project
,PRJ.UID ProjectID
,SCP.Title Scope
,SCP.ScopeID
,TSK.Title WorkItem
,TSK.StartDate TaskStartDate
,TSK.EndDate TaskEndDate
,PRJ.ProgramID
,PR.Program
,PR.PortfolioID
,PF.Portfolio
,TSK.StatusID
,ST.Status
,TSK.TaskID
,TSK.EstimateHrs
,(isnull(SCP.EstimateARCH,0) + isnull(SCP.EstimateBA,0) + isnull(SCP.EstimateDev,0) + isnull(SCP.EstimatePM,0) + isnull(SCP.EstimateQA,0) + isnull(SCP.EstimateRM,0)) as ScopeEstimateHrs
--SCP.EstimateARCH + SCP.EstimateBA +SCP.EstimateDev +SCP.EstimatePM +SCP.EstimateQA +SCP.EstimateRM as ScopeEstimateHrs
FROM Tasks TSK WITH(NOLOCK)
INNER JOIN dbo.Scope SCP WITH(NOLOCK) ON TSK.ScopeID = SCP.ScopeID
INNER JOIN dbo.tb_Project PRJ WITH(NOLOCK)ON TSK.ProjectID = PRJ.UID
INNER JOIN dbo.tb_Program PR WITH(NOLOCK) ON PR.UID=PRJ.ProgramID
INNER JOIN dbo.tb_Portfolio PF WITH(NOLOCK)ON PF.UID=PR.PortfolioID
LEFT OUTER JOIN dbo.TasksResource TSKRES WITH(NOLOCK)ON TSKRES.TaskID = TSK.TaskID
LEFT OUTER JOIN dbo.tb_Resource RES WITH(NOLOCK) ON RES.UID = TSKRES.ResourceID
LEFT JOIN dbo.tb_Division DIV WITH(NOLOCK) ON RES.DivisionID = DIV.UID
LEFT JOIN dbo.tb_Status ST WITH(NOLOCK) ON TSK.StatusID=ST.UID /*relating with the high level work items */
WHERE (PRJ.UID = @Project OR @Project = -1)
AND (PRJ.ProgramID = @Program OR @Program = -1)
AND (PRJ.PortfolioID =@Portfolio OR @Portfolio = -1)
,/*columns used in 2 cte's are taken in below maindata*/
MainData (AllocationDate,Division,DivisionID,ResourceName,ResourceEmailID,ResourceID,Project,ProjectID
,Scope,ScopeID,WorkItem,TaskStartDate,TaskEndDate
,ProgramID ,Program,PortfolioID ,Portfolio,StatusID,Status,TaskID,EstimateHrs,ScopeEstimateHrs,Allocated)
AS
( SELECT
Datematrix.*
,Allocation.*
,CASE WHEN ISDATE(TaskStartDate)=1 THEN 1 ELSE 0 END AS Allocated
FROM Datematrix FULL OUTER JOIN Allocation
ON ( Datematrix.AllocationDate>= Allocation.TaskStartDate
AND Datematrix.AllocationDate<=Allocation.TaskEndDate
)INSERT INTO #TempTable
SELECT * FROM MainData
OPTION (MAXRECURSION 0);this way the code goes...please help.. i need my query to be tuned..!!thanks in advance..
lucky

When asking performance related questions, it is usually a bad idea to use pseudo code. In this case, I am referring to the fact that your "temtable" declaration is invalid, and the fact that it is unclear where the local variables and/or parameter originate
from.
In your query, you are using the "optional parameter" pattern for local variables and/or parameters @Project, @Program and @Portfolio. I therefore assume that we are talking about a stored procedure here.
In stored procedures, optional parameters often have a negative effect on performance. You can cancel some of that effect by adding the OPTION(RECOMPILE) hint (assuming it is part of the stored procedure, and we are talking about parameters, not local variables).
Also, you could consider using a calendar table instead of the Datematrix CTE. Reason for that is, that it is now probably a difficult join with Allocation, because the optimizer probably hasn't established that Datematrix is a unique range of dates. Also,
it will not have any index. A calendar table with unique index on the date can help.
The rest is probably up to the indexes on the base tables. Since you did not post any DDL, I can't comment on that. Lack of proper indexes are usually the biggest reason of Select performance problems.
Gert-Jan

Tuning query performance

Similar Messages

Maybe you are looking for