Oracle Essbase 9 Implementation Guide- P72 doc

Advanced Techniques [ 340 ] When you actually get to tuning your system always keep in mind that what you read here, learn from others, or even glean from Oracle system documentation, is in most cases to be taken as guidelines for your own individual situation. The actual actions you'll be performing, when you are tuning your database, are items like adjusting several optional cache sizes through both the EAS and in the Essbase system conguration le or Essbase.cfg. You may also be taking steps to alter the order of the dimensions in the database outline. We know this isn't really performance related but it is very important! If there were anything that could be considered as a weakness anywhere in Essbase, it would be the Essbase security le or Essbase.sec. Because this le is more or less open all the time for system I/O operations, there is a high potential for the le to become corrupted in the event of a power outage or other serious event. If you do encounter a situation where the server needs to be rebooted unexpectedly, we highly recommend that before you restart the server or the Essbase service, you make a backup copy of the Essbase.sec le. The le itself can be found in the Essbase\bin folder. The shape of your database outline What are they talking about when we refer to the shape of an Essbase outline? How can an Essbase database outline have a shape? Well conceptually every Essbase database outline has a shape. What you want to be concerned with is what shape your outline has. Believe it or not, the shape of your outline is one of the most important considerations for overall database performance, but it is still a guideline. There will be times when this guideline simply will not work for you. Everyone knows what an hourglass looks like, right? An hourglass is wide at the ends and narrow in the middle. Well in most cases, you want your Essbase database outline to have the shape of an hourglass, really. The hourglass outline Here is what we mean by all of this shape nonsense. The shape is determined by the size and storage type of the dimensions in the Essbase database outline. It is generally recognized in the Essbase community that the optimal arrangement for your database outline is as follows: This material is copyright and is licensed for the sole use by Paul Corcorran on 5th July 2009 8601 ave. p #1, , lubbock, , 79423 Download at Boykma.Com Chapter 9 [ 341 ] • Largest Dense dimensions Ñ Most members • Smallest Dense dimensions Ñ Least members • Smallest aggregating Sparse dimensions Ñ Least members and usual consolidations • Largest aggregating Sparse dimensions Ñ Most members and usual consolidations • Non-aggregating Sparse dimensions Ñ Can have many or few members but little to no consolidations By looking at the following screenshot, you will see the recommended dimension structure, as seen in the EAS Database Properties screen: Notice how even with relatively few members, the database outline has the dimensions structured as recommended, wide at the ends and narrow in the middle. Just like an hourglass. The reason for this is the same as was given in Chapter 5 on calculation scripts. The structure of the database is extremely important to the functioning of the database. What the hourglass shape will tend to do is help keep the database block size down to manageable levels for optimal performance during calculations and data loads. This material is copyright and is licensed for the sole use by Paul Corcorran on 5th July 2009 8601 ave. p #1, , lubbock, , 79423 Download at Boykma.Com Advanced Techniques [ 342 ] While this database outline shape methodology will work for most situations, there are times when it will not. For example, in a large parts database, you may need to place your parts dimension last, regardless of the fact that it may have many parent/child consolidations. Database block size As previously mentioned, database block size is an important and integral part of overall database performance. From calculating the database, to retrieving data into a Microsoft Excel spreadsheet, bigger data blocks in an Essbase database usually mean slower performance. Of course, the number and type of dimensions directly affect the database data block size. The suggested ideal database data block size is between 50KB and 200KB. The really ideal block size is less than 100KB or in the 50KB to 80KB range. The number of dense dimensions in the database greatly affects the data block size, so the ideal recommended number of data dimensions in an Essbase database should be from 5 to 7. Of course, there are times when these recommendations are just not possible, but most applications will t within these parameters. Looking at the previous screenshot you can see the Statistics page of the Database Properties screen from the EAS tool. This screen tells you all there is to know about your database data block set up. It will be on this screen you will verify if the changes you have made to your Essbase outline have actually helped with block size, block usage, or block density. This material is copyright and is licensed for the sole use by Paul Corcorran on 5th July 2009 8601 ave. p #1, , lubbock, , 79423 Download at Boykma.Com Chapter 9 [ 343 ] Database conguration settings There are many database caches and settings available to help you with optimizing your database. As you know, optimally storing your data is the job of a properly congured database outline. A properly congured outline can also have an effect on calculation performance, data load performance, and data retrieval performance. Data retrieval buffers When it comes to loading, retrieving, calculating, and extracting your data, performance optimizing is the job of caches and buffers. During reporting, data retrieval cache and buffer settings are used to obtain optimal retrievals of the data. One pair of settings that you cannot go wrong with is the Data retrieval buffers settings, found on the General tab of the Database Properties screen (seen below). The memory used by these buffers is only allocated when an Essbase retrieve is executed from a Microsoft Excel spreadsheet or when an Essbase report script is executed. Because of this you can increase the retrieval buffer and the retrieval sort buffer sizes until you get the results you need, all the way upto the maximum size of 100,000 KB, which is 100MB. Best of all you will not rob the system of memory when they are not in use. These data cache settings are particularly useful when you are reporting on or retrieving larger amounts of dynamically calculated data. This material is copyright and is licensed for the sole use by Paul Corcorran on 5th July 2009 8601 ave. p #1, , lubbock, , 79423 Download at Boykma.Com Advanced Techniques [ 344 ] Data cache settings On the Caches tab of the Database Properties screen (seen below), you will nd an assortment of database cache settings that are congurable by the administrator through EAS. The rst option, Cache memory locking, will actually retain the memory needed for the database caches at all times. In order to set the Cache memory locking to true, you should use the Direct I/O memory setting on the Storage tab. The Direct I/O setting uses the memory set by the File Cache and does not consume Essbase server memory when not in use. By default, this is set to false. While this may give slight improvement during data loads, we have never noticed any real difference in day-to-day operations by checking this option. You may as well let the system enjoy the use of the memory until it is needed by one of these caches. One thing you will notice about Essbase is that it is certainly not bashful. Essbase will almost always use as much of the system resources that you allow. For the Index cache setting, you might as well use the maximum of 10240KB, which is 10MB. The Index cache setting sets the size of the buffer that is used to hold index page les in memory. The system will only grab this extra memory when it needs it and it will certainly use it, especially during large data loads. This material is copyright and is licensed for the sole use by Paul Corcorran on 5th July 2009 8601 ave. p #1, , lubbock, , 79423 Download at Boykma.Com . there were anything that could be considered as a weakness anywhere in Essbase, it would be the Essbase security le or Essbase. sec. Because this le is more or less open all the time for system. recommend that before you restart the server or the Essbase service, you make a backup copy of the Essbase. sec le. The le itself can be found in the Essbase bin folder. The shape of your database. they talking about when we refer to the shape of an Essbase outline? How can an Essbase database outline have a shape? Well conceptually every Essbase database outline has a shape. What you want