[prev in list] [next in list] [prev in thread] [next in thread] 

List:       kde-core-devel
Subject:    Caching local time zone
From:       David Jarvie <lists () astrojar ! org ! uk>
Date:       2006-09-21 9:04:57
Message-ID: 6d3c5f22e9af11f11b8fe6bb331aade0 () webmail ! plus ! net
[Download RAW message or body]

Using KDateTime for date/times in the local time zone can potentially result in very frequent calls to \
KSystemTimeZones::local() which fetches  and returns the current local system time zone. Depending on the \
system, that function may open and read files, and compare their contents.  Even if the files are still \
cached (as would usually be the case on a UNIX system when the function calls are made in quick \
succession), the  overhead in file system function calls makes me feel uneasy when the function could be \
called many times a second if arrays of date/time values  are being converted to or from the local time \
zone.

Plainly, the system time zone is not going to change frequently, so I think that it would be better to \
cache it and only reread it periodically. I  propose to set a timer to refresh it once a minute. Any \
comments/objections?

Note that this caching applies to the time *zone* (e.g. "Europe/Paris"). It has no impact on the handling \
of daylight saving time shifts which will  still be handled without any time lag.

--
David Jarvie.
KAlarm author & maintainer.
http://www.astrojar.org.uk/linux/kalarm.html


[prev in list] [next in list] [prev in thread] [next in thread]