Its not a question of their solution not working. Its that it takes a lot more resources on the read than the alternative.
On Aug 14, 2013, at 5:35 PM, lars hofhansl <[email protected]> wrote: > Yep. > > 1. highly selective indexes + point gets -> global inverted index tables > 2. less selective indexes + queries returning many rows -> "local" indexes, > such as the Huawei solution. > > Of course it's not quite that black and white. Global indexes that serve > index covered queries (where the query can be answered from the index alone) > would also work in many cases of non-selective queries. > > In the end it is quite simple (IMHO): > If a query retrieves data from only a single region, you want to able to hone > into that region quickly, via a piece of global information. > If on the other hand a query returns data from many regions, you're better > off handling the filtering locally. > > Just my $0.02. > > -- Lars > > > ________________________________ > From: Andrew Purtell <[email protected]> > To: "[email protected]" <[email protected]> > Sent: Wednesday, August 14, 2013 1:52 PM > Subject: Re: [ANNOUNCE] Secondary Index in HBase - from Huawei > > > On Wed, Aug 14, 2013 at 8:45 AM, Michael Segel > <[email protected]>wrote: > >> This isn't too bad if you're doing a simple query against one index. You >> can do the work by RS and then join the results from all RS. >> >> However… what happens if you have two indexes and your result set is going >> to be the intersection of the indexes? >> >> Or you're going to do a join between two tables using the indexes to limit >> the result set? >> >> Now your design breaks down quickly. >> > > You may have just described their design assumptions. > > I'm not endorsing this per se, but suggesting it is not a good idea on > account it can't live up to the requirements of a pretty particular > strawman seems a step too far. > > Maybe someone from Huawei can talk a bit here about successful use cases? > >> You could also look at Lucene which we did a PoC a few years back. > > A certain large technology company has an HBase full text index built on > Lucene that might be offered as a contribution at some point. From what I > know of it, there are a different set of tradeoffs and it certainly won't > work for everyone, and not because the people working on it were not smart > enough to find a silver bullet. > > -- > Best regards, > > - Andy > > Problems worthy of attack prove their worth by hitting back. - Piet Hein > (via Tom White) The opinions expressed here are mine, while they may reflect a cognitive thought, that is purely accidental. Use at your own risk. Michael Segel michael_segel (AT) hotmail.com
