This is obviously not normal. So something is going wrong - probably a 
misbehaving client. If this happens again after creating a brand new 
account on the device, capture the *sync* log from this attempt at 
create a bug report (you may email me the sync log directly if privacy 
is a concern).
Sounds like a runaway client.
Yup, that's me :)

Thank you for your work and commentary on the bug report.

I am not sure what "misbehaves". Synchronisation works since I updated 
my Android phone, but then sometimes all calender entries vanish from 
the phone, after some hours, a block of them are back there again, 
only to vanish hours later again.

At the same time, I had problems (end in the end was not able to) log 
into Horde any more via Web Interface from my Linux Laptop. There were 
over 80 apache2-processes running, but neither the apache2-log nor the 
system log (debugging in Horde was not active at the time) were 
conclusive.

I am not sure what is going wrong, but I want to try to help you find out :)
Instead of asking stupid question here by opening an unneccesary bug 
report I might better ask those question in IRC #horde ...
Is '@mrubinsk' the correct way to address you there?

Thank you so far, and many greetings,

Mazze

This is how ActiveSync works. In order to "push" new data to the 
client the client maintains a connection with the server and performs 
a PING loop waiting for changes. Each iteration of the loop polls the 
history backend for changes. This (along with some ActiveSync state 
management) is what all the SQL queries you see are for.

I'm not sure what you consider "very busy", but it's definitely doing 
"something useful". If you are unable to login because of the 
ActiveSync connections, you need to increase the number of connections 
your server can handle.

If you feel that ActiveSync is misbehaving, you can enable the sync 
log and open another ticket with the details of what is going wrong.

I use Horde with SQLite, and when I use Activesync to synchronize data 
with my Android 4.0.4 smartphone, Horde gets very busy for hours, even 
after disabling data connection from the smartphone.

I will provide the debug log showing one hour of output, but from what 
I could say not doing something useful, probably just looping.

Please have a look into that, because even with the web interface, it 
is sometimes not possible to get logged in before timeout.

Thank you for your great work, and greetings,

Mazze