Hbase filters

[Matus Zamborsky <za...@b-ideas.eu>]

Is anybody using filters when scanning table? I recently created 
"(HBASE-1790) filters are not working correctly" and submitted a patch, 
but latter I found that stateful filters are still not working. I have 
already rewrited the HRegion::nextInternal function and filters(not 
submitted patch yet). As I see it, there were more problems.
1. filters are applyed before deleted rows were discarted(so they were 
count in when scaning, this is problem for PageFilter)
2. filters like PageFilter reset their state in reset function, but this 
function is called in HRegion::nextInternal, so it would be good to 
mention in javadoc for Filter::reset, where in the process of filtering 
is this method called.
3. last problem is a question, why there is Filter::filterRow called in 
HRegion::nextInternal, when it should be called after 
Filter::filterKeyValue(KeyValue) which is not called in 
HRegion::nextInternal.

So my last question is, is anybody using filters, because their are 
seriously not working correctly at all. And if there is someone, which 
filter do you use?