From d720a4019460b6c284d0473249303c349df60a1f Mon Sep 17 00:00:00 2001 From: Sean Owen Date: Mon, 19 Sep 2016 09:38:25 +0100 Subject: [SPARK-17297][DOCS] Clarify window/slide duration as absolute time, not relative to a calendar ## What changes were proposed in this pull request? Clarify that slide and window duration are absolute, and not relative to a calendar. ## How was this patch tested? Doc build (no functional change) Author: Sean Owen Closes #15142 from srowen/SPARK-17297. --- .../src/main/scala/org/apache/spark/sql/functions.scala | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'sql') diff --git a/sql/core/src/main/scala/org/apache/spark/sql/functions.scala b/sql/core/src/main/scala/org/apache/spark/sql/functions.scala index 18e736ab69..960c87f60e 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/functions.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/functions.scala @@ -2606,12 +2606,15 @@ object functions { * The time column must be of TimestampType. * @param windowDuration A string specifying the width of the window, e.g. `10 minutes`, * `1 second`. Check [[org.apache.spark.unsafe.types.CalendarInterval]] for - * valid duration identifiers. + * valid duration identifiers. Note that the duration is a fixed length of + * time, and does not vary over time according to a calendar. For example, + * `1 day` always means 86,400,000 milliseconds, not a calendar day. * @param slideDuration A string specifying the sliding interval of the window, e.g. `1 minute`. * A new window will be generated every `slideDuration`. Must be less than * or equal to the `windowDuration`. Check * [[org.apache.spark.unsafe.types.CalendarInterval]] for valid duration - * identifiers. + * identifiers. This duration is likewise absolute, and does not vary + * according to a calendar. * @param startTime The offset with respect to 1970-01-01 00:00:00 UTC with which to start * window intervals. For example, in order to have hourly tumbling windows that * start 15 minutes past the hour, e.g. 12:15-13:15, 13:15-14:15... provide @@ -2660,11 +2663,15 @@ object functions { * The time column must be of TimestampType. * @param windowDuration A string specifying the width of the window, e.g. `10 minutes`, * `1 second`. Check [[org.apache.spark.unsafe.types.CalendarInterval]] for - * valid duration identifiers. + * valid duration identifiers. Note that the duration is a fixed length of + * time, and does not vary over time according to a calendar. For example, + * `1 day` always means 86,400,000 milliseconds, not a calendar day. * @param slideDuration A string specifying the sliding interval of the window, e.g. `1 minute`. * A new window will be generated every `slideDuration`. Must be less than * or equal to the `windowDuration`. Check - * [[org.apache.spark.unsafe.types.CalendarInterval]] for valid duration. + * [[org.apache.spark.unsafe.types.CalendarInterval]] for valid duration + * identifiers. This duration is likewise absolute, and does not vary + * according to a calendar. * * @group datetime_funcs * @since 2.0.0 -- cgit v1.2.3