Search a virtual index
Once you properly install and configure your virtual indexes, you can create reports and visualize data as you would against data in a traditional Splunk index. Using virtual indexes alongside traditional Splunk Enterprise indexes, you can gather data from the virtual index alone; or you can query both local and virtual indexes for a single report.
For the most part, you can create reports for virtual indexes much as you would for local indexes. For more information about creating reports, see the Splunk Enterprise Search Manual.
Due to the size and the nature of Hadoop datastores, there are certain Splunk Enterprise index behaviors that cannot be duplicated:
- Splunk Analytics for Hadoop currently doesn't support real-time searching of Hadoop data, although preview functionality is available.
- Data is not always returned as quickly as data is returned for a local index.
Since events are not sorted, any search command which depends on implicit time order will not work exactly the way you'd expect. (For example: head, delta, or transaction.) This means that a few search commands operate differently when used on virtual indexes, mostly because of the way Hadoop reports timestamps.
You can still use these commands, and may particularly want to when creating a single report for local and virtual indexes, but you should be aware of how they operate and return data differently.
How Splunk Analytics for Hadoop uses search language
For the most part, you can use Splunk Enterprise search language to create your reports. However, because Splunk Analytics for Hadoop does not support strict requirements on the order of events, there are a few differences.
The following commands are not supported when the search includes a virtual indexes:
The following commands work on virtual indexes, but their results may differ from Splunk. This is because in Splunk Analytics for Hadoop, descending time order of events is not guaranteed:
dedup(Since the command cannot distinguish order within an HDFS directory to pick the item to remove, Splunk Analytics for Hadoop will choose the item to remove based on modified time, or file order.)
Header extractions to avoid when working with virtual indexes
This documentation applies to the following versions of Splunk® Enterprise: 6.5.7, 7.0.0, 7.0.1, 7.0.2, 7.0.3, 7.0.4, 7.0.5, 7.0.6, 7.0.7, 7.0.8, 7.0.9, 7.0.10, 7.0.11, 7.0.13, 7.1.0, 7.1.1, 7.1.2, 7.1.3, 7.1.4, 7.1.5, 7.1.6, 7.1.7, 7.1.8, 7.1.9, 7.1.10, 7.2.0, 7.2.1, 7.2.2, 7.2.3, 7.2.4, 7.2.5, 7.2.6, 7.2.7, 7.2.8, 7.2.9, 7.2.10, 7.3.0, 7.3.1, 7.3.2, 7.3.3, 7.3.4, 7.3.5, 7.3.6, 7.3.7, 7.3.8, 7.3.9, 8.0.0, 8.0.1, 8.0.2, 8.0.3, 8.0.4, 8.0.5, 8.0.6, 8.0.7, 8.0.8, 8.0.9, 8.0.10, 8.1.0, 8.1.1, 8.1.2, 8.1.3, 8.1.4, 8.1.5, 8.1.6, 8.1.7, 8.1.8, 8.1.9, 8.1.10, 8.2.0, 8.2.1, 8.2.2, 8.2.3, 8.2.4, 8.2.5, 8.2.6, 9.0.0