Large calendars won't sync

[VegArchie]

I have a large calendar, going back 20+ years. I find that DAVx5 can't sync, fails to sync, or rarely completes a sync if I set the sync interval larger than 365 days.

This calendar used to be on Google (and synced fine) but was moved to my private, home hosted nextcloud account. The calendar events are there on the nextcloud server. When I try to sync with DAVx5, (on unlimited internal or a large number of days), it syncs indefinitely, never completing. I've only seen it compete once, but the next sync gets stuck.

I'm running android 14, and this issue has persisted on multiple DAVx versions including the current 4.4.0.1-gplay.

Please help.

[VegArchie]

FYI, the calendar, when backed up to a file, is only 8.4MB.

[exstntlmsnthrp]

I could be incorrect with my understanding, but I believe once a full sync is complete, it's only the changes that are synced after that.

I have a fairly large calendar as well (though not quite that large) of about 15 years (transferred from multiple sources) that I have running on Nextcloud and not had any problems.

My first guess would be that there's a chance it might be timing out. Have you optimized your server settings?

Have you enabled verbose logging in Davx⁵ to see what errors might be occurring?

Edit: I did have mine only set to sync the past 365 days. I'm attempting to sync all and see what happens.

[exstntlmsnthrp]

Ok I just completed a full sync. It took just under 1 minute to complete without any errors.

[VegArchie]

Thank you. I will look into the logs. Maybe there is an event somewhere in the past causing a hiccup. This calendar has passed from the Palm Pilot to ical to google to nextcloud over the years. Who knows what gremlins are in there.

[exstntlmsnthrp]

I think another user recently had a similar problem and found an old event that was causing issues. Once removing that event, they were able to sync without problems.

[VegArchie]

I was able to split the ICS file into smaller pieces using this web site: https://brokenvectors.github.io/

That allowed me to re-upload the calendar as multiple calendars Archive1, Archive2 etc.

I was then able to more easily find the culprits in two of the splits. A bunch of weird calendar entries titled "." and being recurring, but only showing once. After deleting them, all seems good! Being that there is 30,000 entries, it's better I keep them in separate 5,000-entry chunks.