huaxingao opened a new pull request #34311: URL: https://github.com/apache/spark/pull/34311
### What changes were proposed in this pull request? Push down Sample to data source for better performance. The new interface is implemented using JDBC for POC and end to end test. ### Why are the changes needed? Reduce IO and improve performance For SAMPLE, e.g. `SELECT * FROM t TABLESAMPLE (1 PERCENT)`, Spark retrieves all the data from table and then return 1% rows. It will dramatically reduce the transferred data size and improve performance if we can push Sample to data source side. ### Does this PR introduce _any_ user-facing change? Yes. new interface `SupportsPushDownTableSample` ### How was this patch tested? New test -- 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]
