Abdullah Alamoudi created ASTERIXDB-2194:
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Summary: Introduce datasource functions
Key: ASTERIXDB-2194
URL: https://issues.apache.org/jira/browse/ASTERIXDB-2194
Project: Apache AsterixDB
Issue Type: Improvement
Components: COMP - Compiler
Reporter: Abdullah Alamoudi
Assignee: Abdullah Alamoudi
Sometimes, we would like to be able to query system status. For example:
1. Disk space.
2. Number of components of a dataset.
3. Memory usage.
And many others. Being able to query such information and utilize the power of
the query language and the runtime makes a great investigative/diagnostic tool.
Currently, there is no easy way to do that. Such functionality can be achieved
through:
1. External datasets but that takes a lot of work in terms of development and
usage.
2. Use specific diagnostic end points but then that is also a lot of
development work and you end up losing the ability to use the query language.
Current proposal is to introduce datasource functions. A datasource function is
different from normal functions as:
1. Takes constants ( as opposed to variables).
2. Has location constraints "For a start, it can be on all nodes".
An example would be the function dataset_resources(String dataverse, String
dataset);
This function takes a dataverse and a dataset and produce a set of json
representing the disk resources of the dataset.
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