On 30/03/15 20:13, Richard wrote: > > > ------------ Original Message ------------ >> Date: Monday, March 30, 2015 20:04:56 +0100 >> From: Lester Caine <lester@xxxxxxxxxxx> >> >> On 30/03/15 16:41, Larry Martell wrote: >>>>> The use case is that I have a server uptime reporting script >>>>> and it >>>>>>> uses a database of times that the server was able to be >>>>>>> pinged. If there is no entry for a period it indicated the >>>>>>> server was down. So on March 29, running in London, it found >>>>>>> no entries from 1am to 2am and it reported the server was >>>>>>> down for an hour, when in fact the period from 1am to 2am >>>>>>> did not exist because of the switch to summer time. >>>>> >>>>> If you are logging ANYTHING other than UTC then your reporting >>>>> system is the problem. You DISPLAY times using the local time, >>>>> and log everything using a clean UTC time. >>> I 100% agree with you, but this client does not do that. I have >>> told them they should, but they did not want to change. >> >> As Ryan says ... convert to UTC to do the check, but personally >> I'd be looking at why 1amGMT and 2amBST is reporting 2 hours >> rather than 1 hour. I've been through this many years ago now with >> clients who simply recorded the 'time'. Railway timetables never >> used to run over night at that time, but when they started, >> timetables got interesting ;) When the underlying process was >> switched to UTC and all of the hacks to get the correct running >> times were removed the objections were also removed. >> >> I presume that all you get from the database is '1am' or '2am', so >> you just need to add the missing offset information from the >> calendar. So you have 1amGMT and 2amBST to compare. >> > > You can get the information you're after with "zdump -v" of the > zoneinfo file for a timezone, e.g., > > zdump -v GB | grep 2015 > > GB Sun Mar 29 00:59:59 2015 UTC = Sun Mar 29 00:59:59 2015 GMT > isdst=0 gmtoff=0 > GB Sun Mar 29 01:00:00 2015 UTC = Sun Mar 29 02:00:00 2015 BST > isdst=1 gmtoff=3600 > GB Sun Oct 25 00:59:59 2015 UTC = Sun Oct 25 01:59:59 2015 BST > isdst=1 gmtoff=3600 > GB Sun Oct 25 01:00:00 2015 UTC = Sun Oct 25 01:00:00 2015 GMT > isdst=0 gmtoff=0 > > how you deal with it from there is up to you -- there are many > options I would think, including loading it into a DB that you > check. The system TZ files do change from time to time, as the local > rules change, so you'd need to manage for that. Or just use a DateTimeZone object? Larry's original question was about checking if a time was 'within the DST switchover' but that would not help. What is needed is simply the offset for each time in the raw data ... that is if Larry simply has raw times as the data. -- Lester Caine - G8HFL ----------------------------- Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk Rainbow Digital Media - http://rainbowdigitalmedia.co.uk -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
