DEV EPM

Hey guys, how are you? Continuing the Essbase Statistics DW: How to automatically administrate Essbase using ODI series (Part 1 Here), today we’ll talk about Data File Cache and Data Cache.

The data file cache is deprecated, and I don’t know if much people use it, but it’s used to define the maximum size of the data cache. The data file cache is used to hold compressed data files (essn.pag) in memory and is used only when direct I/O option is in effect. To find it maximum size we need to sum all essn.pag files, if possible; otherwise, as large as possible.

We can find this information in EAS edit properties, storage or Maxl query database file information or in Esscmd list files or java using Maxl as we can see here:

EAS	MAXL	ESSCMD	JAVA
Right click in a cube edit properties->Storage	query database sample.basic list all file information;	listfiles “” “sample” “basic”;	maxl.execute(“query database ” + s_application + “.” + s_cube + ” list all file information”);

Now let’s talk about the data cache. The name looks almost the same, but his usage is very different. The data cache is used hold uncompressed data blocks in memory. It has a direct relationship with the Data file cache and the recommended size would be 12.5 % of the summing of all essn.pag files (or 0.125 * Data File Cache size. That is why we even talked about the data file cache and calculated its size before.

The same thing that happens with the index cache happens here with the data cache. If we have too much historical data, we may decrease the optimum size to fit the data usage.

We gather this information in the same way as the data cache file:

EAS	MAXL	ESSCMD	JAVA
Right click in a cube edit properties->Storage	query database sample.basic list all file information;	listfiles “” “sample” “basic”;	maxl.execute(“query database ” + s_application + “.” + s_cube + ” list all file information”);

Then to resume what we talked about in this post:

• The data file cache is used to hold compressed data files (essn.pag) in memory and is used only when direct I/O option is in effect.
• It is calculated by summing all essn.pag files, if possible; otherwise, as large as possible.
• The data cache is used hold uncompressed data blocks in memory.
• The recommended size would be 12.5 % of the summing of all essn.pag files (or 0.125 * Data File Cache size).
• Same case as Index cache, just the working blocks are used (no historical).

I’ll stop here since we have a big one coming and I want to address the Calculator Cache alone in the next post.

Be safe and see you soon.

This entry was posted on February 2, 2021 at 12:13 pm and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.