question

Kalle L. avatar image
Kalle L. asked ·

CAS DB vs. SyntheticMonitoring DB & selective data purge

Hi,

I was looking into the selective data purge functionality (i.e. removing "false positive" / unwanted monitoring results), and noticed first of all that there are separate features for deleting CAS data (via DiagConsole) and the synthetic DB data (via the Synthetic Console). Deleting rows from the SyntheticMonitoring DB apparently has no impact when browsing the data via CAS. Seeing as CAS is the interface we use to browse the data, that is of course where we need to direct the data purge as well. Does it make sense to also delete from SyntheticMonitoring? If I only delete the rows from CAS, will it then later pick up the data from SyntheticMonitoring? I'm trying to understand the relationship between the two databases - if there's some documentation already about this, feel free to link me. The Agent Manager installation instructions do touch on the subject, but it's not quite clear to me yet overall.

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1 Answer

Carol O. avatar image
Carol O. answered ·

Hi,Kalle. In general, as you know, your reporting data will be in the CAS database. So, you may at times need to purge data there.

You will also want to maintain the ESM database to a reasonable size. The best approach here (if your database is not too large currently) is to use the Agent Manager Database Tab to configure the database scheduled maintenance. If your ESM DB is currently too large, you may want to purge some data first using Agent Manager Content Pane Commands and then configure the scheduled maintenance. I hope this helps. Thanks!

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Hi Carol,

Thanks for the response, though my question wasn't so much about database maintenance - I'm trying to understand when does CAS actually read data from the ESM database? And when only from it's own DB? The same kind of selective data purge functionality is there for both CAS and ESM databases, so when is it that I would want to also clean up the unwanted measurements from ESM? Might CAS at some point notice: "ok I have blank data for yesterday, but the ESM DB has all the data available - let me copy everything from there to my DB". So if I want to clean up a specific set of unwanted results, is it enough to do that for CAS, even though the data still remains at ESM DB?

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Hi, Kalle. The CAS never reads data from the ESM database; the ESM database is used by the ESM Console.. ESM prepares transdata files for the CAS, and that data is stored in the CAS database.

Yes, when you want to clean up a specific set of unwanted results in the reports, you only need to purge data from the CAS database. Thanks!

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Hmm, I have to say I'm a bit surprised about this comment: "CAS never reads data from the ESM database; the ESM database is used by the ESM Console". Because for example in the below installation instructions, it says: "CAS stores data for a limited period of time. For that reason, you may choose to install the Enterprise Synthetic database for historical and trend analysis reporting"

https://community.dynatrace.com/community/display/ENTSYM125/Install+Agent+Manager+and+create+database

Also, the fact that the Agent Manager's purge functionality allows me to wipe a specific set of data for an app/transaction/agent/etc. suggests that the data is indeed purged for reporting purposes. Your comment however suggests that the ESM database is there only for general management and administration, and everything related to reporting is only at CAS. So, what am I missing here?

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Hi, Kalle. Thanks for pointing out this in the documentation. We will correct the doc.

We understand that the evolution to the use of the CAS as our reporting engine may cause confusion and may not have been completely reflected in the documentation. In 12.5:

  • the only reporting engine for ESM is the CAS
  • the CAS uses data from the CAS database and now retains ESM data for longer periods of time than in the past.
  • some customers have their own uses of historical data in the ESM database
  • the ESM Console uses the ESM database for configuration and for limited reporting for diagnostic purposes
  • the purge data for the ESM database existed to remove old data (in prep for scheduled maintenance) and unwanted data for the reporting engine that was used in the past prior to the CAS. ESM purge data remains in the product for maintenance only and alternative customer reporting uses, not for CAS reporting.

When you want to clean up a specific set of unwanted results in the CAS reports, you only need to purge data from the CAS database. Thanks!

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Thank you for the thorough answer! Got it now :) The documentation indeed threw me off there.

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Great! I updated that doc and asked the team to look for more places we may have missed. Thanks for pointing this out and for all your patience and diligence!

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