[Evolution] Evolution unresponsive using 'autocomplete', triggers re-download of WebDAV address book

[Michael Wenyon <michael+evolution-list wengam com>]

Autocompleting addresses is generally slow for me, and often freezes
or stops working, then causes my WebDAV address book to re-download
from the WebDAV server. Re-download of my 2,700 entries takes 10
minutes+, during which autocomplete does not work (it makes no
suggestions).

Autocomplete often works for the first entry. But it freezes if I edit the
characters I have typed, for example by deleting the most recent
character entered. Then, the cursor stops flashing and the program
becomes unresponsive for a minute or more. When it comes back, I can
occasionally edit my typed characters and sometimes generate a new
autocomplete suggestion. More often, no suggestion appears, and when I
change to Contacts mode, I discover that the WebDAV address book is
empty and Evolution has begun to download it again from the server from
scratch, a time-consuming process. 

Generally I have difficulty adding a second entry: often I get no
suggestion then I discover that the GUI is frozen and the WebDAV address
book is downloading again.

Evolution 3.12.1 
Operating system: Debian jessie/sid 
Kernel Linux 3.13-1-686-pae (i686) 
Gnome 3.8.4 
WebDAV: OwnCloud server v 6.0.3 running on shared server (Dreamhost) 
Computer: Intel NUC DN2820FYKH with Celeron processor 2.13 GHZ and 4GB RAM, 
with 1 TB Toshiba hybrid HD/SSD

My WebDAV Address Book contains 2,700 entries. It was set up manually
within Evolution, I marked it as default, marked it for autocomplete
and marked it for copying the book content locally for offline
operation. The connection with my OwnCloud server is a secure https
connection.

The Personal Address Book ('On This Computer') contains a single entry
and is not marked for autocomplete use.