OLAP Cache for Query Performance

Hi Experts,
I have below 2 Questions before we implement OLAP Cache for our Queries:
1) We have 15 imporatant queries - which do NOT have any variable/selection screen.
(question here is will it work for those kind of queries which dont have any selection screen/ variant ? ) --> client wants to prime the cache for few queries which dont have variable screen.
In this case, say if data is later filtered on any CHAR , will it take the data from Cache?
2) I have a query which initially will have few characteristics in the drill down when we first execute and users would be drilling down on many other characteristics after that. So if I want to fill OLAP cache for this query then what is the best way so that each drilldown in the query gets data from cache.
Thank you,
-Su

Hi Raghavendra,
Thanks for your response.
For first Question, Do you mean , even if we do not have any Selection varaibale on Query--we still can fill OLAP cache for it for its all values (i.e. No selection means "*") ?
If this is the case, then what we need to defile in General Precalculation (Variable assignment) while creating a new setting for the query.
Thanks,
-Su

Similar Messages

Pre-fill the OLAP cache for a query on Data change event of infoprovider

Hi Gurus,
I have to pre-fill the OLAP cache for a query,which has bad performance.
I read a doc 'Periodic Jobs and Tasks in SAP BW'
which suggested sum steps to do this
i hav created the setting for Bex broadcasting for scheduling job Execution with data change in info provider
thereafter doc says "an event has to be raised in the process chain which loads the data to this InfoProvider.When the process chain executes the process u201CTrigger Event Data Change (for Broadcaster)u201D, an event is raised to inform the Broadcaster that the query can be filled in the OLAP cache."
how can this b done please provide with sum proper steps
Answers are always appreciated.
Thanks.

Hi
U need to create a process chain or use the existing process chain which you are using to load your current solution, just add event change process type in the process chian and inside it add the info provider which are going to be affected.
Once you are done with this go to the broadcaster and create new setting for that query...you will see the option for event data chainge in infoprovider just choose that and create the settings.
hope it helps

How to empty out Olap Cache for a query?

Hi experts,
I think the olap cache for a query should be resetted to zero after a data load (right?), if i have understood well how it works. Where can i check the olap cache for the query? I'd like to ckeck the change of the Olap Cache for a specific query.
I checkt in the Cache Monitor but I haven't found any data.
Francesco

Hi
You can use the Transaction code RSRCACHE
Regards
N Ganesh

Filling OLAP Cache for 3 Bex queries

Dear Experts,
Here, We would required to fill the OLAP cache for four bex queries using the Broadcaster Settings.
can any one please suggest for the following.
how to schedule the OLAP chache filling for 3 different queries at a time. do we need to perform this activity individually for three times for three different queries or can we club three queries and do schedule using only one varaint.
Request you to suggests the steps for performing this activity
Thanks in advance,
Mannu

Hey,
this may be useful for you.
http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/f048c590-31a4-2c10-8599-bd01fabb93d4?quicklink=index&overridelayout=true
Regards,
Kiran

Is aggregate DB index is required for query performance

Hi,
Cube mange tab when i check for the aggregate DB index it shows red, here my doubt is, is the DB index is required for query performance
is the check statics should be in green?
Please let me know
Regards,
Kiran

Hi,
Yes it improves the reports performance..
Using the Check Indexes button, you can check whether indexes already exist and whether these existing indexes are of the correct type (bitmap indexes).
Yellow status display: There are indexes of the wrong type
Red status display: No indexes exist, or one or more indexes are faulty
You can also list missing indexes using transaction DB02, pushbutton Missing Indexes. If a lot of indexes are missing, it can be useful to run the ABAP reports SAP_UPDATE_DBDIFF and SAP_INFOCUBE_INDEXES_REPAIR.
See SAP Help
http://help.sap.com/saphelp_nw2004s/helpdata/en/80/1a6473e07211d2acb80000e829fbfe/content.htm
Thanks
Reddy

Step by step usage of RSRT for Query performance

Hi,
Can I get any step by step document, how to test the query performance using RSRT?
I am sorry if this has been posted already. I tried my best to search for this but could not find this
Thanks
Ananth

Olap cache settings
RSRT u2013> choose a query u2013>properties u2013> Cache Mode: Persistent Cache per Application server, Persistence Mode: Flat File.
RSRT
http://www.sap-press.de/download/dateien/1049/sappress_bw_performance_optimization_guide_080.pdf

Warming up File System Cache for BDB Performance

Hi,
We are using BDB DPL - JE package for our application.
With our current machine configuration, we have
1) 64 GB RAM
2) 40-50 GB -- Berkley DB Data Size
To warm up File System Cache, we cat the .jdb files to /dev/null (To minimize the disk access)
e.g
// Read all jdb files in the directory
p = Runtime.getRuntime().exec("cat " + dirPath + "*.jdb >/dev/null 2>&1");
Our application checks if new data is available every 15 minutes, If new Data is available then it clears all old reference and loads new data along with Cat *.jdb > /dev/null
I would like to know that if something like this can be done to improve the BDB Read performance, if not is there any better method to Warm Up File System Cache ?
Thanks,

We've done a lot of performance testing with how to best utilize memory to maximize BDB performance.
You'll get the best and most predictable performance by having everything in the DB cache. If the on-disk size of 40-50GB that you mention includes the default 50% utilization, then it should be able to fit. I probably wouldn't use a JVM larger than 56GB and a database cache percentage larger than 80%. But this depends a lot on the size of the keys and values in the database. The larger the keys and values, the closer the DB cache size will be to the on disk size. The preload option that Charles points out can pull everything into the cache to get to peak performance as soon as possible, but depending on your disk subsystem this still might take 30+ minutes.
If everything does not fit in the DB cache, then your best bet is to devote as much memory as possible to the file system cache. You'll still need a large enough database cache to store the internal nodes of the btree databases. For our application and a dataset of this size, this would mean a JVM of about 5GB and a database cache percentage around 50%.
I would also experiment with using CacheMode.EVICT_LN or even CacheMode.EVICT_BIN to reduce the presure on the garbage collector. If you have something in the file system cache, you'll get reasonably fast access to it (maybe 25-50% as fast as if it's in the database cache whereas pulling it from disk is 1-5% as fast), so unless you have very high locality between requests you might not want to put it into the database cache. What we found was that data was pulled in from disk, put into the DB cache, stayed there long enough to be promoted during GC to the old generation, and then it was evicted from the DB cache. This long-lived garbage put a lot of strain on the garbage collector, and led to very high stop-the-world GC times. If your application doesn't have latency requirements, then this might not matter as much to you. By setting the cache mode for a database to CacheMode.EVICT_LN, you effectively tell BDB to not to put the value or (leaf node = LN) into the cache.
Relying on the file system cache is more unpredictable unless you control everything else that happens on the system since it's easy for parts of the BDB database to get evicted. To keep this from happening, I would recommend reading the files more frequently than every 15 minutes. If the files are in the file system cache, then cat'ing them should be fast. (During one test we ran, "cat *.jdb > /dev/null" took 1 minute when the files were on disk, but only 8 seconds when they were in the file system cache.) And if the files are not all in the file system cache, then you want to get them there sooner rather than later. By the way, if you're using Linux, then you can use "echo 1 > /proc/sys/vm/drop_caches" to clear out the file system cache. This might come in handy during testing. Something else to watch out for with ZFS on Solaris is that sequentially reading a large file might not pull it into the file system cache. To prevent the cache from being polluted, it assumes that sequentially reading through a large file doesn't imply that you're going to do a lot of random reads in that file later, so "cat *.jdb > /dev/null" might not pull the files into the ZFS cache.
That sums up our experience with using the file system cache for BDB data, but I don't know how much of it will translate to your application.

Explain plan for Query performance

Hi Gurus,
I need to improve the performance of a procedure. The procedure has the below QUery. I dont have Idea on how to imrpove the perf by seeing the explain plan. Can anyone please help me to explain where I need to change the code.
The below are the code and Explain plan for the same.
-----------Code----------------------------
SELECT IV_STORECODE AS STORECODE,
                               TO_CHAR(RD.ITEMCODE) AS ITEMCODE,
                               C.ITEMCATEGORYNAME,
                               ISUB.ITEMSUBCATEGORY1NAME
                          FROM RECEIPTS R
                         INNER JOIN RECEIPTDETAILS RD
                            ON R.RECEIPTID = RD.RECEIPTID
                         INNER JOIN ITEMCOMPANY IC
                            ON IC.ITEMCODE = RD.ITEMCODE
                         INNER JOIN ITEMCATEGORY C
                            ON IC.ITEMCATEGORY = C.ITEMCATEGORYID
                         LEFT OUTER JOIN ITEMSUBCATEGORY1 ISUB
                            ON ISUB.ITEMSUBCATEGORY1ID = IC.ITEMSUBCATEGORY1
                           AND ISUB.ITEMSUBCATEGORY1ID IN
                               (SELECT ITEMSUBCATEGORY1ID
                                  FROM ITEMSUBCATEGORY1
                                 WHERE ITEMCATEGORYID = IV_ITEMCATEGORY)
                         INNER JOIN STORE SE
                            ON SE.STORECODE = R.STORECODE
                         WHERE R.STORECODE = IV_STORECODE
                           AND SE.HOSPITALID = IV_HOSPITALID
                           AND TRUNC(R.CREATEDDATE) BETWEEN V_FROMDATE AND
                               V_TODATE
                           AND R.STATUSID NOT IN (99, 5)
                              AND
                               (IV_DRUGTYPE IS NULL OR
                               IC.DRUGTYPECATEGORYID = IV_DRUGTYPE)
                        UNION
                        SELECT IV_STORECODE AS STORECODE,
                               TO_CHAR(STD.ITEMCODE) AS ITEMCODE,
                               C.ITEMCATEGORYNAME,
                               ISUB.ITEMSUBCATEGORY1NAME
                          FROM STOCKTRANSACTION ST
                         INNER JOIN STOCKTRANSACTIONDETAILS STD
                            ON ST.STOCKTRANSACTIONID = STD.STOCKTRANSACTIONID
                         INNER JOIN ITEMCOMPANY IC
                            ON IC.ITEMCODE = STD.ITEMCODE
                         INNER JOIN ITEMCATEGORY C
                            ON IC.ITEMCATEGORY = C.ITEMCATEGORYID
                          LEFT OUTER JOIN ITEMSUBCATEGORY1 ISUB
                            ON ISUB.ITEMSUBCATEGORY1ID = IC.ITEMSUBCATEGORY1
                           AND ISUB.ITEMSUBCATEGORY1ID IN
                               (SELECT ITEMSUBCATEGORY1ID
                                  FROM ITEMSUBCATEGORY1
                                 WHERE ITEMCATEGORYID = IV_ITEMCATEGORY)
                         INNER JOIN STORE SE
                            ON SE.STORECODE = ST.STORECODE
                         WHERE ST.STORECODE = IV_STORECODE
                           AND SE.HOSPITALID = IV_HOSPITALID
                           AND TRUNC(ST.CREATEDDATE) BETWEEN V_FROMDATE AND
                               V_TODATE
                           AND ST.STATUS <> 99
                           AND STD.ITEMCODE NOT LIKE '%#%'
                           AND
                               (IV_DRUGTYPE IS NULL OR
                               IC.DRUGTYPECATEGORYID = IV_DRUGTYPE)
                        UNION
                        SELECT D.STORECODE,
                               TO_CHAR(D.ITEMCODE) AS ITEMCODE,
                               C.ITEMCATEGORYNAME,
                               ISUB.ITEMSUBCATEGORY1NAME
                          FROM DAILYINVENTORY D
                         INNER JOIN ITEMCOMPANY IC
                            ON IC.ITEMCODE = D.ITEMCODE
                         INNER JOIN ITEMCATEGORY C
                            ON IC.ITEMCATEGORY = C.ITEMCATEGORYID
                          LEFT OUTER JOIN ITEMSUBCATEGORY1 ISUB
                            ON ISUB.ITEMSUBCATEGORY1ID = IC.ITEMSUBCATEGORY1
                           AND ISUB.ITEMSUBCATEGORY1ID IN
                               (SELECT ITEMSUBCATEGORY1ID
                                  FROM ITEMSUBCATEGORY1
                                 WHERE ITEMCATEGORYID = IV_ITEMCATEGORY)
                         INNER JOIN STORE SE
                            ON SE.STORECODE = D.STORECODE
                         WHERE D.STORECODE = IV_STORECODE
                           AND SE.HOSPITALID = IV_HOSPITALID
                           AND TRUNC(D.UPDATEDDATE) <= V_TODATE
                           AND D.QTY > 0
                           AND D.ITEMCODE NOT LIKE '%#%'
                           AND C.ITEMCATEGORYID = IV_ITEMCATEGORY
                              AND (IV_DRUGTYPE IS NULL OR
                               IC.DRUGTYPECATEGORYID = IV_DRUGTYPE)
                           AND (IV_SUBITEMCATEGORY IS NULL OR
                               ISUB.ITEMSUBCATEGORY1ID = IV_SUBITEMCATEGORY) Will post the explain plan ..
Thanks in advance..

Ensure you also include all the other information people will need to help you, e.g. database version, table structures/relationships and cardinalities, row counts etc.
See the two threads linked to in the FAQ: {message:id=9360003}

Olap cache not storing result sets for certain queries

Hi - another cache question
my result set for a query is not getting set in OLAP CACHE - the query variable level is stored ok but not the result set.
different queries store the result sets ok.
there is nothing in the query or cube properties that should disable the caching of the result set.
there is plenty of space available and there has not been any changes to the query or data loaded or aggregates changed.
any ideas?
cheers - Neil

I would do a performance check in RSRT2. This will usually give you some additional information related to olap cache.
Hope that helps.

How to improve query performance built on a ODS

Hi,
I've built a report on FI_GL ODS (BW3.5). The report execution time takes almost 1hr.
Is there any method to improve or optimize th query performance that build on ODS.
The ODS got huge volume of data ~ 300 Million records for 2 years.
Thanx in advance,
Guru.

Hi Raj,
Here are some few tips which helps you in improving ur query performance
Checklist for Query Performance
1. If exclusions exist, make sure they exist in the global filter area. Try to remove exclusions by subtracting out inclusions.
2. Use Constant Selection to ignore filters in order to move more filters to the global filter area. (Use ABAPer to test and validate that this ensures better code)
3. Within structures, make sure the filter order exists with the highest level filter first.
4. Check code for all exit variables used in a report.
5. Move Time restrictions to a global filter whenever possible.
6. Within structures, use user exit variables to calculate things like QTD, YTD. This should generate better code than using overlapping restrictions to achieve the same thing. (Use ABAPer to test and validate that this ensures better code).
7. When queries are written on multiproviders, restrict to InfoProvider in global filter whenever possible. MultiProvider (MultiCube) queries require additional database table joins to read data compared to those queries against standard InfoCubes (InfoProviders), and you should therefore hardcode the infoprovider in the global filter whenever possible to eliminate this problem.
8. Move all global calculated and restricted key figures to local as to analyze any filters that can be removed and moved to the global definition in a query. Then you can change the calculated key figure and go back to utilizing the global calculated key figure if desired
9. If Alternative UOM solution is used, turn off query cache.
10. Set read mode of query based on static or dynamic. Reading data during navigation minimizes the impact on the R/3 database and application server resources because only data that the user requires will be retrieved. For queries involving large hierarchies with many nodes, it would be wise to select Read data during navigation and when expanding the hierarchy option to avoid reading data for the hierarchy nodes that are not expanded. Reserve the Read all data mode for special queriesu2014for instance, when a majority of the users need a given query to slice and dice against all dimensions, or when the data is needed for data mining. This mode places heavy demand on database and memory resources and might impact other SAP BW processes and tasks.
11. Turn off formatting and results rows to minimize Frontend time whenever possible.
12. Check for nested hierarchies. Always a bad idea.
13. If "Display as hierarchy" is being used, look for other options to remove it to increase performance.
14. Use Constant Selection instead of SUMCT and SUMGT within formulas.
15. Do review of order of restrictions in formulas. Do as many restrictions as you can before
calculations. Try to avoid calculations before restrictions.
17. Turn off warning messages on queries.
18. Check to see if performance improves by removing text display (Use ABAPer to test and validate that this ensures better code).
19. Check to see where currency conversions are happening if they are used.
20. Check aggregation and exception aggregation on calculated key figures. Before aggregation is generally slower and should not be used unless explicitly needed.
21. Avoid Cell Editor use if at all possible.
22. Make sure queries are regenerated in production using RSRT after changes to statistics, consistency changes, or aggregates.
23. Within the free characteristics, filter on the least granular objects first and make sure those come first in the order.

Query Performance - Query very slow to run

I have built a query to show payroll costings per month per employee by cost centres for the current fiscal year. The cost centres are selected with a hierarchy variable - it's quite a latrge hierarchy. The problem is the query takes ages to run - nearly ten minutes. It's built on a DSO so I cant aggregate it. Is there anything I can do to improve performance.

Hi Joel,
Walkthrough Checklist for Query Performance:
1. If exclusions exist, make sure they exist in the global filter area. Try to remove exclusions by subtracting out inclusions.
2. Use Constant Selection to ignore filters in order to move more filters to the global filter area. (Use ABAPer to test and validate that this ensures better code)
3. Within structures, make sure the filter order exists with the highest level filter first.
4. Check code for all exit variables used in a report.
5. Move Time restrictions to a global filter whenever possible.
6. Within structures, use user exit variables to calculate things like QTD, YTD. This should generate better code than using overlapping restrictions to achieve the same thing. (Use ABAPer to test and validate that this ensures better code).
7. When queries are written on multiproviders, restrict to InfoProvider in global filter whenever possible. MultiProvider (MultiCube) queries require additional database table joins to read data compared to those queries against standard InfoCubes (InfoProviders), and you should therefore hardcode the infoprovider in the global filter whenever possible to eliminate this problem.
8. Move all global calculated and restricted key figures to local as to analyze any filters that can be removed and moved to the global definition in a query. Then you can change the calculated key figure and go back to utilizing the global calculated key figure if desired
9. If Alternative UOM solution is used, turn off query cache.
10. Set read mode of query based on static or dynamic. Reading data during navigation minimizes the impact on the R/3 database and application server resources because only data that the user requires will be retrieved. For queries involving large hierarchies with many nodes, it would be wise to select Read data during navigation and when expanding the hierarchy option to avoid reading data for the hierarchy nodes that are not expanded. Reserve the Read all data mode for special queriesu2014for instance, when a majority of the users need a given query to slice and dice against all dimensions, or when the data is needed for data mining. This mode places heavy demand on database and memory resources and might impact other SAP BW processes and tasks.
11. Turn off formatting and results rows to minimize Frontend time whenever possible.
12. Check for nested hierarchies. Always a bad idea.
13. If "Display as hierarchy" is being used, look for other options to remove it to increase performance.
14. Use Constant Selection instead of SUMCT and SUMGT within formulas.
15. Do review of order of restrictions in formulas. Do as many restrictions as you can before calculations. Try to avoid calculations before restrictions.
16. Check Sequential vs Parallel read on Multiproviders.
17. Turn off warning messages on queries.
18. Check to see if performance improves by removing text display (Use ABAPer to test and validate that this ensures better code).
19. Check to see where currency conversions are happening if they are used.
20. Check aggregation and exception aggregation on calculated key figures. Before aggregation is generally slower and should not be used unless explicitly needed.
21. Avoid Cell Editor use if at all possible.
22. Make sure queries are regenerated in production using RSRT after changes to statistics, consistency changes, or aggregates.
23. Within the free characteristics, filter on the least granular objects first and make sure those come first in the order.
24. Leverage characteristics or navigational attributes rather than hierarchies. Using a hierarchy requires reading temporary hierarchy tables and creates additional overhead compared to characteristics and navigational attributes. Therefore, characteristics or navigational attributes result in significantly better query performance than hierarchies, especially as the size of the hierarchy (e.g., the number of nodes and levels) and the complexity of the selection criteria increase.
25. If hierarchies are used, minimize the number of nodes to include in the query results. Including all nodes in the query results (even the ones that are not needed or blank) slows down the query processing. The u201Cnot assignedu201D nodes in the hierarchy should be filtered out, and you should use a variable to reduce the number of hierarchy nodes selected.
Regards
Vivek Tripathi

Filling Cache for a Web Template

HI Folks,
We are in BI7.0. We have some reports which are taking huge amount of time to get executed. So we would like to fill the OLAP cache for these reports. I know the concept of pre calculating web templates in BW3.5. I am not sure, whether do we have to adopt the same concept here in BI7.0 or not?
Please let us know which process better suits our requirement in BI7.0 and provide the steps to perform it accordingly.
Any links, documents or PDFs on this topic are most welcome.
Many thanks.
regards,
SN

Hi,
Please have a look into the below article.
http://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/f048c590-31a4-2c10-8599-bd01fabb93d4
Regards,
Raghavendra.

Warming up the OLAP cache

Hi,
I would like to schedule execution of some queries in order to put the results in the OLAP cache for fast use.
Each user run the query with very restricted selection: one period, one node in the CostCenter hierarchy and one currency type! All the selections are obligatory and for single values.
I created a "super" query with the same characteristics, all in the rows or columns, with not mandatory variables, ...
I scheduled the "super" query and it create an entry in the OLAP cache.
When I now run the production query (other query on the same cube, for one node, one period, one currency) the system doesn't use the OLAP cache, but create a new line in the OLAP cache.
It is impossible to schedule every combination.
Is there a way to worm up the cache with a different Q?
Should the seedling be done with Broadcaster or Reporting Agent (in NW2004s)? I think this should be the same ?!
Any suggestion to fill the cache for my situation?
Thanks, Tom

The OLAP cache is at a query level, so to warm up the cache, you must run the actual query that the users will run, not just a similar or "super" query that is similar.
SDN has some doc on effectively using Global cache which would be good to review.
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/9f4a452b-0301-0010-8ca6-ef25a095834a
The other key thing to understand is how the setting on variable "Can be changed during query navigation" works. If this setting is NOT set on your variables, then in order for a query to access the data in the cache, the query must have been run previously with the exact same variable values, as the varaiable values get saved as part of the cached info.
Selecting the "Can be changed during navigation" variable setting changes the way the system considers the variable - it behaves as a filter. This has some implications with way prompts for variables appear to the user, so there are user impacts. In BEx, a variable is normally presented for input when you first run the query and then whenver you refresh it, but when you change the variable setting to Can be changed..., the variable prompt will be presented teh frist time the query is run, but NOT when a refresh is done, it now behaces as if you added a filter to the query.
So if you change all the variables (or create new ones) used bythe query to Can be changed..., then run your query thru reporting agent or info broadcasting wide open, or with restrictions that encompass all your user's query executions, the subsequent user executions will use the global Olap cache.

Reseeding cache for users with role based security

I have role based security and trying to set up cache by purging all cache and later seeding cache by query. The query would be different for different users. What is the best way to purge all cache and reseed cache for administrator as well as all users. The EPT would purge cache based on updated tables. But how do I next go about reseeding cache for better performance to all the users. Thanks.

I have created an ibot with the following:
General - Normal Priority, Personalized (recipient's data visibility)
Conditional Request - example_report
Schedule - some schedule
Recipients - Me(administrator) and User1
Destinations - Oracle BI Server cache
when the ibot runs 2 cache entries are created (for the 2 recipients).
I have the report (example_report) on the dashboard (1 dashboard, 1 page, 1 report).
After the ibot runs:
When the administrator logs in first, there is a cache hit on the report. Followed by when the User1 logs in there is NO cache hit.
On the other hand when the User1 logs in first, there is a cache hit on the report. Followed by when the administrator logs in there is no cache hit. The query log creates a Query issued to the database instead of cache hit on query.
The User1 has a data level security.
Please let me know where was I making an error in setting the ibot and how to get the cache seeding work for the different users with different role based security.
Thanks for your inputs.

How to improve Query Performance

Hi Friends...
I Want to improve query performance.I need following things.
1.What is the process to findout the performance?. Any transaction code's and how to use?.
2.How can I know whether the query is running good or bad ,ie. in performance praspect.
3.I want to see the values i.e. how much time it is taking to run?. and where the defect is?.
4.How to improve the query performance?. After I did the needfull things to improve performance, I want to see the query execution time. i.e. it is running fast or not?.
Eg..
Eg 1.   Need to create aggregates.
Solution: where can I create aggregates?. Now I'm in production system. So where I need to create? .i.e. indevelopment or in Quality or in Production system?.
Any chenges I need to do in Development?.Because I'm in Production system.
So please tell me solution for my questions.
Thanks
Ganga
Message was edited by: Ganga N

hi ganga
please refer oss note :557870 : Frequently asked questions on query performance
also refer to
Prakash's weblog
/people/prakash.darji/blog/2006/01/27/query-creation-checklist
/people/prakash.darji/blog/2006/01/26/query-optimization
performance docs on query
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/3f66ba90-0201-0010-ac8d-b61d8fd9abe9
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
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/064fed90-0201-0010-13ae-b16fa4dab695
This is the oss notes of FAQ on query performance
1. What kind of tools are available to monitor the overall Query Performance?
1.     BW Statistics
2.     BW Workload Analysis in ST03N (Use Export Mode!)
3.     Content of Table RSDDSTAT
2. Do I have to do something to enable such tools?
Yes, you need to turn on the BW Statistics:
RSA1, choose Tools -> BW statistics for InfoCubes
(Choose OLAP and WHM for your relevant Cubes)
3. What kind of tools is available to analyze a specific query in    detail?
1.     Transaction RSRT
2.     Transaction RSRTRACE
4. Do I have an overall query performance problem?
i. Use ST03N -> BW System load values to recognize the problem. Use the number given in table 'Reporting - InfoCubes:Share of total time (s)' to check if one of the columns %OLAP, %DB, %Frontend shows a high   number in all Info Cubes.
ii. You need to run ST03N in expert mode to get these values
5. What can I do if the database proportion is high for all queries?
Check:
1.     If the database statistic strategy is set up properly for your DB platform (above all for the BW specific tables)
2.     If database parameter set up accords with SAP Notes and SAP Services   (EarlyWatch)
3.     If Buffers, I/O, CPU, memory on the database server are exhausted?
4.     If Cube compression is used regularly
5.     If Database partitioning is used (not available on all DB platforms)
6. What can I do if the OLAP proportion is high for all queries?
Check:
1.     If the CPUs on the application server are exhausted
2.     If the SAP R/3 memory set up is done properly (use TX ST02 to find bottlenecks)
3.     If the read mode of the queries is unfavourable (RSRREPDIR, RSDDSTAT, Customizing default)
7. What can I do if the client proportion is high for all queries?
Check whether most of your clients are connected via a WAN connection and the amount of data which is transferred   is rather high.
8. Where can I get specific runtime information for one query?
1.     Again you can use ST03N -> BW System Load
2.     Depending on the time frame you select, you get historical data or current data.
3.     To get to a specific query you need to drill down using the InfoCube name
4.      Use Aggregation Query to get more runtime information about a   single query. Use tab All data to get to the details.   (DB, OLAP, and Frontend time, plus Select/ Transferred records, plus number of cells and formats)
9. What kind of query performance problems can I recognize using ST03N
   values for a specific query?
(Use Details to get the runtime segments)
1.     High Database Runtime
2.     High OLAP Runtime
3.     High Frontend Runtime
10. What can I do if a query has a high database runtime?
1.     Check if an aggregate is suitable (use All data to get values "selected records to transferred records", a high number here would be an indicator for query performance improvement using an aggregate)
2.     o Check if database statistics are update to data for the   Cube/Aggregate, use TX RSRV output (use database check for statistics and indexes)
3.     Check if the read mode of the query is unfavourable - Recommended (H)
11. What can I do if a query has a high OLAP runtime?
1.     Check if a high number of Cells transferred to the OLAP (use "All data" to get value "No. of Cells")
2.     Use RSRT technical Information to check if any extra OLAP-processing is necessary (Stock Query, Exception Aggregation, Calc. before   Aggregation, Virtual Char. Key Figures, Attributes in Calculated   Key Figs, Time-dependent Currency Translation) together with a high number of records transferred.
3.     Check if a user exit Usage is involved in the OLAP runtime?
4.     Check if large hierarchies are used and the entry hierarchy level is as deep as possible. This limits the levels of the hierarchy that must be processed. Use SE16 on the inclusion tables and use the List of Value feature on the column successor and predecessor to see which entry level of the hierarchy is used.
5.     Check if a proper index on the inclusion table exist
12. What can I do if a query has a high frontend runtime?
1.     Check if a very high number of cells and formatting are transferred   to the Frontend (use "All data" to get value "No. of Cells") which   cause high network and frontend (processing) runtime.
2.     Check if frontend PC are within the recommendation (RAM, CPU MHz)
3.     Check if the bandwidth for WAN connection is sufficient
REWARDING POINTS IS THE WAY OF SAYING THANKS IN SDN
CHEERS
RAVI

OLAP Cache for Query Performance

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