[Koha-zebra] Updating zebradb

[Tümer Garip]

Hi,

This is the continuation of building zebradb thread.

As suggested by Sebastian we moved to zebra 1.4 but our problems have
not gone away.
Version 1.4 not being a release version we moved back to 1.3.34 to do
further tests.

Updating zebradb with just one process is not a problem. i.e a script
that reads 2000 random records modifies a flag and updates the zebradb
works OK. If you do not have shadow files search respone slows down
drastically but if you update with shadow files and do a single commit
everything looks fine.

But that is not a real life situation and it real life everything is
still hectic.
In real life you have about 20 searches going on and about 10-20 update
requests in queue. In those situations zebra can not handle things. If
you use shadow files we had a crashed db. I dont know the mechanics
behind zebra but when you have:

Update
 |
 |
 |		Update
 |		 |
Commit	 |
		 |
		 |
		commit

Processes like this going on is it safe? Is each commit knows what to
commit? I can not comment on this but just can say that it does not
work.

So we changed file handling not to use shadow files. Now we get lots of
TIMEOUT errors from updates and then zebraserver crashes. Well at least
the zebradb stayed intact. 

We tried all sorts of other things (like looping the process until it
updates) but all in vain.

I can definitely say that we have not managed to get zebra updates
coming from multiple clients work whatever we tried. Either ZEBRA does
not like this sort of updating or we have a long way of debugging. 

A little bit disappointed but not lost hope. We'll keep on trying and
reporting.

Regards
Tumer
NEU Grand Library
CYPRUS