MaxGekk opened a new pull request #28441: URL: https://github.com/apache/spark/pull/28441
### What changes were proposed in this pull request? Skip timestamps rebasing after a global threshold when there is no difference between Julian and Gregorian calendars. This allows to avoid checking hash maps of switch points, and fixes perf regressions in `toJavaTimestamp()` and `fromJavaTimestamp()`. ### Why are the changes needed? The changes fix perf regressions of conversions to/from external type `java.sql.Timestamp`. Before (see the PR's results https://github.com/apache/spark/pull/28440): ``` ================================================================================================ Conversion from/to external types ================================================================================================ OpenJDK 64-Bit Server VM 1.8.0_252-8u252-b09-1~18.04-b09 on Linux 4.15.0-1063-aws Intel(R) Xeon(R) CPU E5-2670 v2 @ 2.50GHz To/from Java's date-time: Best Time(ms) Avg Time(ms) Stdev(ms) Rate(M/s) Per Row(ns) Relative ------------------------------------------------------------------------------------------------------------------------ From java.sql.Timestamp 376 388 10 13.3 75.2 1.1X Collect java.sql.Timestamp 1878 1937 64 2.7 375.6 0.2X ``` After: ``` ================================================================================================ Conversion from/to external types ================================================================================================ OpenJDK 64-Bit Server VM 1.8.0_252-8u252-b09-1~18.04-b09 on Linux 4.15.0-1063-aws Intel(R) Xeon(R) CPU E5-2670 v2 @ 2.50GHz To/from Java's date-time: Best Time(ms) Avg Time(ms) Stdev(ms) Rate(M/s) Per Row(ns) Relative ------------------------------------------------------------------------------------------------------------------------ From java.sql.Timestamp 249 264 24 20.1 49.8 1.7X Collect java.sql.Timestamp 1503 1523 24 3.3 300.5 0.3X ``` Perf improvements in average of: 1. From java.sql.Timestamp is ~ 34% 2. To java.sql.Timestamps is ~16% ### Does this PR introduce _any_ user-facing change? No ### How was this patch tested? By existing test suites `DateTimeUtilsSuite` and `RebaseDateTimeSuite`. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
