[SPARK-31874][SQL] Use FastDateFormat as the legacy fractional formatter
#28678
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Test build #123317 has finished for PR 28678 at commit
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MaxGekk
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FastDateFormat as the legacy fractional formatterFastDateFormat as the legacy fractional formatter
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@cloud-fan @HyukjinKwon @juliuszsompolski Please, review this PR. |
MaxGekk
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FastDateFormat as the legacy fractional formatterFastDateFormat as the legacy fractional formatter
MaxGekk
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FastDateFormat as the legacy fractional formatterFastDateFormat as the legacy fractional formatter
cloud-fan
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May 31, 2020
| TimestampFormatter.defaultPattern, | ||
| zoneId, | ||
| TimestampFormatter.defaultLocale, | ||
| LegacyDateFormats.FAST_DATE_FORMAT, |
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is it the same with Spark 2.4?
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Spark 2.4 uses SimpleDateFormat but output of FastDateFormat and SimpleDateFormat for the concrete pattern yyyy-MM-dd HH:mm:ss is the same. At least, all our tests show no difference.
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thanks, merging to master/3.0! |
cloud-fan
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May 31, 2020
…atter ### What changes were proposed in this pull request? 1. Replace `SimpleDateFormat` by `FastDateFormat` as the legacy formatter of `FractionTimestampFormatter`. 2. Optimise `LegacyFastTimestampFormatter` for `java.sql.Timestamp` w/o fractional part. ### Why are the changes needed? 1. By default `HiveResult`.`hiveResultString` retrieves timestamps values as instances of `java.sql.Timestamp`, and uses the legacy parser `SimpleDateFormat` to convert the timestamps to strings. After the fix #28024, the fractional formatter and its companion - legacy formatter `SimpleDateFormat` are created per every value. By switching from `LegacySimpleTimestampFormatter` to `LegacyFastTimestampFormatter`, we can utilize the internal cache of `FastDateFormat`, and avoid parsing the default pattern `yyyy-MM-dd HH:mm:ss`. 2. The second change in the method `def format(ts: Timestamp): String` of `LegacyFastTimestampFormatter` is needed to optimize the formatter for patterns without the fractional part and avoid conversions to microseconds. ### Does this PR introduce _any_ user-facing change? No ### How was this patch tested? By existing tests in `TimestampFormatter`. Closes #28678 from MaxGekk/fastdateformat-as-legacy-frac-formatter. Authored-by: Max Gekk <max.gekk@gmail.com> Signed-off-by: Wenchen Fan <wenchen@databricks.com> (cherry picked from commit 47dc332) Signed-off-by: Wenchen Fan <wenchen@databricks.com>
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What changes were proposed in this pull request?
SimpleDateFormatbyFastDateFormatas the legacy formatter ofFractionTimestampFormatter.LegacyFastTimestampFormatterforjava.sql.Timestampw/o fractional part.Why are the changes needed?
HiveResult.hiveResultStringretrieves timestamps values as instances ofjava.sql.Timestamp, and uses the legacy parserSimpleDateFormatto convert the timestamps to strings. After the fix [SPARK-31254][SQL] Use the current session time zone inHiveResult.toHiveString#28024, the fractional formatter and its companion - legacy formatterSimpleDateFormatare created per every value. By switching fromLegacySimpleTimestampFormattertoLegacyFastTimestampFormatter, we can utilize the internal cache ofFastDateFormat, and avoid parsing the default patternyyyy-MM-dd HH:mm:ss.def format(ts: Timestamp): StringofLegacyFastTimestampFormatteris needed to optimize the formatter for patterns without the fractional part and avoid conversions to microseconds.Does this PR introduce any user-facing change?
No
How was this patch tested?
By existing tests in
TimestampFormatter.