SAP HANA Smart Data Streaming: What You’ve Been Asking Us Lately, March 2017 Edition
The February blahs may have slowed you down, but they didn’t stop you from asking us questions! Here are some of the questions and answers from the past month.
Immediate failures are the best clue that something went wrong with your installation, but even seemingly innocuous errors may mean you should take a closer look under the hood.
I’m trying to create a server connection to streaming for the first time, but get an error.
So you’ve done a fresh install of SAP HANA and smart data streaming 1.0 SP 11, but can’t get streaming to connect to the server. Do you have a local role assigned? If not, that’s likely the problem. Running the ./hdbmodify –add_local_roles=streaming command after you install the streaming studio plugin is an important step, so don’t skip it! See How to Install SAP HANA Smart Data Streaming and SAP HANA on the Same Host for more information.
Note that this command is only applicable to 1.0 SP 11 and earlier installations.
My streaming project compiles, but doesn’t run.
If your log file says that The connection manager failed to start, ensure that you installed SAP HANA and smart data streaming on a supported operating system. These include versions of SLES and Redhat but not necessarily CentOS. For a full list of operating systems for streaming see SAP Note 2366318, and for HANA see SAP Note 2235581. Check out the original question, Unable to run SDS project, for the full log file errors to look for if you encounter a similar issue.
How do I connect to smart data streaming using the Streaming Web Output adapter?
Trying to connect a data source, such as Raspberry Pi, directly to smart data streaming will result in errors like Connection could not be established. You’ll need to first connect the Streaming Web output adapter to the Streaming Web Service and connect that to a smart data streaming server.
Make sure to use the appropriate configuration settings with this in mind, including using a port number different from the one you would use when connecting to the smart data streaming server. Take a look at the Streaming Web Output Adapter section for more information on configuring the adapter, and see the original question, Error in Connecting SDS with Raspberry Pi, for more information on this particular issue.
How do I remove old data from an aggregate window with the AGING clause?
Using the AGING clause won’t remove the old data, it will just flag it. Use a KEEP policy instead. Remember that the KEEP clause can be used twice in one window: once on its own to apply retention policies to the window, and another time with FROM to determine the age of the data being aggregated (as in FROM events no older than 3 months). Look at the FROM Clause and KEEP Clause documentation to learn more about using these clauses.
Do you have questions of your own? Ask a Question and add smart data streaming as the primary tag to get it posted to our developer page where one of our product experts can help you. Check out our complete list of smart data streaming questions to see if someone has already had the same question as you. Thanks for reading!