Want to know The Truth About CPM?

22 August 2014

Essbase is available for download

It’s out

I must give a hat tip to Steph who commented on my post as I didn’t know about the patch release.

Two things that I found interesting

  1. No stated (although I could swear that Gabby said there was) improvements to Hybrid BSO
  2. Fragmentation (storage engine not stated, but I am not aware of significant ASO .dat fragmentation) no longer matters
Here's the relevant quote with emphasis added:
Historically, fragmentation has been perceived as degrading performance. However, with advances in hardware, memory, and disk architectures, the correlation between fragmentation and performance is no longer significant. Furthermore, several enhancements have been made to algorithms within Essbase, making the older statistics pertaining to fragmentation less relevant. Oracle recommends the use of the latest efficient storage systems to store Essbase data files, such as Storage Area Network (SAN) or flash.

That’s going to blow up the rule of thumb “defrag for performance”.   <grin>  One thing that the documentation does not note is when this became true.  Presumably it’s in the .502 patch as that’s when this went into the ReadMe but sometimes documentation lags a bit, particularly when it doesn’t address a defect.

Oracle do go on to state that fragmentation is still somewhat important because it increases disk requirements:
The second implication of fragmentation is related to increase in the size of data files. Oracle recommends regular monitoring of the number of blocks and the data file size. If the size of the data files increases even though the number of data blocks remains the same, and available disk space is diminishing, consider taking steps to reduce fragmentation.

So Essbase continues to eat disk when it’s fragmented but that’s only a worry if the database is constrained on space.  Verrrrry interesting.

I’m not sure how one would test this – I suppose a series of benchmarks against a db when it’s 100% defragmented and then when it is nicely fragmented would do it although per their comment, if the statistics are no longer totally relevant, how will you know?  I look forward to someone other than myself doing the testing.  <even bigger grin>

There’s quite a bit more to the ReadMe so you should Read The Whole Thing (login to Oracle Support required).

Be seeing you.

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