When searching by tag, there is no need to join with Event; especially when
just counting results or determining first/last digest_order (for navigation).
(For the above "no need" to be actually true, digest_order was denormalized
into EventTag).
The above is implemented in `search_events_optimized`.
Further improvements:
* the bounds of `digest_order` are fetched only once; for first/last this info
is reused.
* explicitly pass `event_qs_count` to the templates
* non-event pages used to calculate a "last event" to generate a tab with a
correct event.id; since we simply have the "last" idiom, better use that.
this also makes clear the "none" idiom was never needed, we remove it again.
Results:
Locally (60K event DB, 30K events on largest issue) my testbatch now
runs in 25% of time (overall).
* The effect on the AND-ing are in fact very large (13% runtime remaining)
* The event details page is not noticably improved.
Now that we have eviction, events may disappear. Deal with it:
* event-specific 404 that still allows for navigation
* first/last buttons
* navigation to prev/next when prev/next is not just 1 step away
* don't use HttpRedirect for "lookup based" views
in principle, the thing you were looking for might go missing in-between
drawback: these URLs are not "stable"
* issue.event_count to digested_event_count
* event.ingest_order to event.digest_order
* issue.ingest_order to digest_order
This is generally more correct/explicit, and is also in preparation
of doing work on-digest (which may or may not happen)
Klaas van Schelven