Hi all, One of the difficulties is that time intervals and periods have different use cases, but they share the same type in Avro.
Often, a time interval is used within a day only. Thus, it can be expressed using milliseconds. Larger periods usually span entire days, and don't need milliseconds. But they do need months and days. Although translating the Avro type to a specific language may be tricky (Avro durations support more values than Java intervals and periods, for example), I think it's best to keep it as is. Kind regards, Oscar -- Oscar Westra van Holthe - Kind <[email protected]> Op wo 13 apr. 2022 23:11 schreef kyle minmaxcorp.com <[email protected]>: > If I'm being honest I would only do days, hours, milliseconds. Months > doesn't really have a defined standard (unless I know the datetime that I > am adding to or subtracting to). I can't add or subtract 30 days and know > that it is a month. The actual is same for a year. So, based on some of the > implementations I'm seeing. The first value isn't month, but should be > referred to as 30 day intervals. > > > On April 13, 2022 12:05 PM Micah Kornfield <[email protected]> > wrote: > > > > > > Hi Kyle, > > > We would have to know the start datetime and end datetime to calculate > the actual values. > > I believe this is intended. There are two types of durations, those that > relate to calendars (you need to know when they start) and those that are > independent of any notion of calendar and measure an absolute time delta. > Both are useful. It's unfortunate that there isn't common terminology, > Avro's duration is referred to as interval in other systems. > > > > > The duration logical type represents an amount of time defined by the > number of weeks, days, and milliseconds. > > Changing to weeks seems like a fundamentally breaking change? What value > do weeks have over days? For context in SQL systems there are generally two > different durations (Year-Month) and (Days/Seconds). Some systems combine > the two (e.g. Postgres and BigQuery). > > > > Cheers, > > Micah > > > > > > On Wed, Apr 13, 2022 at 11:22 AM kyle minmaxcorp.com ( > http://minmaxcorp.com) <[email protected]> wrote: > > > When it comes to a duration type, both years and months are not > standard increments. We would have to know the start datetime and end > datetime to calculate the actual values. > > > > > > Current Text: > > > > > > Duration > > > > > > The duration logical type represents an amount of time defined by a > number of months, days and milliseconds. This is not equivalent to a number > of milliseconds, because, depending on the moment in time from which the > duration is measured, the number of days in the month and number of > milliseconds in a day may differ. Other standard periods such as years, > quarters, hours and minutes can be expressed through these basic periods. > > > > > > > > > > > > A duration logical type annotates Avro fixed type of size 12, which > stores three little-endian unsigned integers that represent durations at > different granularities of time. The first stores a number in months, the > second stores a number in days, and the third stores a number in > milliseconds. > > > > > > > > > > > > Updated text: > > > > > > Duration > > > > > > The duration logical type represents an amount of time defined by the > number of weeks, days, and milliseconds. Other standard periods such as > hours, minutes, and seconds can be expressed through these basic periods. > > > > > > > > > > > > A duration logical type annotates Avro fixed type of size 12, which > stores three little-endian unsigned integers that represent durations at > different granularities of time. The first stores a number in weeks, the > second stores a number in days, and the third stores a number in > milliseconds. > > > > > > > > > Additional discussions: > > > > https://issues.apache.org/jira/browse/AVRO-739?focusedCommentId=14083646&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-14083646 >
