adarshsanjeev opened a new pull request, #15689: URL: https://github.com/apache/druid/pull/15689
Druid currently does not allow export of tables in a programmatic manner. While is is possible to download results from a SELECT query, this relies on writing the results to a single query report, which cannot support large datasets. An export syntax which writes the results in a desired format directly to an external location (such as s3 or hdfs) would be useful. The scope could be explanded later to also have a directory structure that already partitions the data. This PR adds export capabilities to insert/replace statements by using EXTERN as a destination: ``` (INSERT/REPLACE) INTO EXTERN(<external source function>) AS <format>[(key1=value1,key2=value2)] [OVERWRITE ALL] <select query> ``` For example: A statement to export all rows from a table into S3 as CSV files would look like ``` REPLACE INTO EXTERN(s3(uri="s3://outputdirectory/", username=...)) AS CSV OVERWRITE ALL SELECT * FROM wikipedia ``` INSERT statements append to the files found at the destination, while replace deletes any files found at the root path and creates the new files. #### Release note <!-- Give your best effort to summarize your changes in a couple of sentences aimed toward Druid users. If your change doesn't have end user impact, you can skip this section. For tips about how to write a good release note, see [Release notes](https://github.com/apache/druid/blob/master/CONTRIBUTING.md#release-notes). --> - Adds export syntax to MSQ, as a part of INSERT and REPLACE statements. <hr> ##### Key changed/added classes in this PR * `sql/src/main/codegen/includes/common.ftl` * `sql/src/main/codegen/includes/replace.ftl` * `IngestHandler` <hr> <!-- Check the items by putting "x" in the brackets for the done things. Not all of these items apply to every PR. Remove the items which are not done or not relevant to the PR. None of the items from the checklist below are strictly necessary, but it would be very helpful if you at least self-review the PR. --> This PR has: - [ ] been self-reviewed. - [ ] using the [concurrency checklist](https://github.com/apache/druid/blob/master/dev/code-review/concurrency.md) (Remove this item if the PR doesn't have any relation to concurrency.) - [ ] added documentation for new or modified features or behaviors. - [ ] a release note entry in the PR description. - [ ] added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links. - [ ] added or updated version, license, or notice information in [licenses.yaml](https://github.com/apache/druid/blob/master/dev/license.md) - [ ] added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader. - [ ] added unit tests or modified existing tests to cover new code paths, ensuring the threshold for [code coverage](https://github.com/apache/druid/blob/master/dev/code-review/code-coverage.md) is met. - [ ] added integration tests. - [ ] been tested in a test Druid cluster. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
