Bug 18078 – All files seen as changed after Daylight Saving time change (Windows only)

Bug 18078 - All files seen as changed after Daylight Saving time change (Windows only)

Summary:

All files seen as changed after Daylight Saving time change (Windows only)

Status:	RESOLVED FIXED

Product:	Logitech Media Server
Classification:	Unclassified
Component:	Scanner
Version:	7.8.0
Platform:	PC Windows (legacy)

Importance:	-- normal (vote)
Target Milestone:	7.7.x
Assigned To:	Michael Herger

URL:
Keywords:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2014-03-21 21:07 UTC by Jim McAtee
Modified:	2016-03-15 10:19 UTC (History)
CC List:	0 users

See Also:
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Description Jim McAtee 2014-03-21 21:07:04 UTC

Due to how Windows handles Daylight Savings time changes on NTFS volumes, a new & changed scan following a DST time change will see all files as having different modified timestamps.

This results in an unusually slow new & changed scan twice a year for most users running LMS on Windows.

Comment 1 Michael Herger 2015-03-09 10:26:27 UTC

Do you happen to remember how to fake a DST change? I'm trying to get it to re-scan my library by changing timezones, disabling automatic DST changes etc, but to no avail.

Comment 2 Jim McAtee 2015-03-09 17:31:09 UTC

I don't recall faking it for testing. I probably tested by using a backup of the library database containing timestamps from prior to the time change.

Comment 3 Jim McAtee 2015-03-09 23:12:58 UTC

I just tested it and a timezone change on my system _does_ cause a new & changed scan to rescan all files in the library. Not sure why it wouldn't work for you. This is using local files on an NTFS volume.

Also, modifying the timestamps in the database by one hour via SQL should be equivalent to having a pre-time-change database. The following should effectively set all timestamps to what they were before the recent change.

update tracks
set timestamp = timestamp - 3600;

Comment 4 Michael Herger 2015-03-10 07:32:57 UTC

> update tracks
> set timestamp = timestamp - 3600;

Oh, that was too obvious for me to figure out :-). Thanks!

Comment 5 Michael Herger 2015-03-11 14:45:45 UTC

I think I finally fixed this. With a little luck we'll know in about two weeks, when Europe has switched to DST, too. If that test is positive, I'm going to back-port this change.

Comment 6 Jim McAtee 2016-03-15 08:45:46 UTC

Yep. I think it's fixed in 7.9. I would think it's safe to back-port to 7.8

Comment 7 Michael Herger 2016-03-15 10:19:34 UTC

Thanks! Back-ported to 7.7.6 & 7.8.1.