Re: Issue with ALLOW FILTERING
Hi Sávio, I am really surprised by this. Could anyone explain why ALLOW FILTERING only is allowed when using secondary index and not together with a PRIMARY KEY? I'm struggling to see any reason for it not being supported. Also, I don't believe the CQL specification makes it entirely clear that only secondary indexes are supported. Or is it considered implementation specific under what circumstances ALLOW FILTERING can be used? Thanks, Jens On Tue, Aug 5, 2014 at 8:11 PM, Sávio S. Teles de Oliveira savio.te...@cuia.com.br wrote: You need to create an index on attribute *c.* 2014-08-05 9:24 GMT-03:00 Jens Rantil jens.ran...@tink.se: Hi, I'm having an issue with ALLOW FILTERING with Cassandra 2.0.8. See a minimal example here: https://gist.github.com/JensRantil/ec43622c26acb56e5bc9 I expect the second last to fail, but the last query to return a single row. In particular I expect the last SELECT to first select using the clustering primary id and then do filtering. I've been reading https://cassandra.apache.org/doc/cql3/CQL.html#selectStmt ALLOW FILTERING and can't wrap my head around why this won't work. Could anyone clarify this for me? Thanks, Jens -- Atenciosamente, Sávio S. Teles de Oliveira voice: +55 62 9136 6996 http://br.linkedin.com/in/savioteles Mestrando em Ciências da Computação - UFG Arquiteto de Software CUIA Internet Brasil
Re: Issue with ALLOW FILTERING
On Wed, Aug 6, 2014 at 9:41 AM, Jens Rantil jens.ran...@tink.se wrote I'm struggling to see any reason for it not being supported. The time to implement it, plus a bunch of internal implementation reasons that makes it not as trivial to support as you seem to suggest it is (of course, this is open source, you are welcome to have a look if that's a particular itch you want to scratch; there is even a JIRA ticket: https://issues.apache.org/jira/browse/CASSANDRA-6377). Or is it considered implementation specific under what circumstances ALLOW FILTERING can be used? Currently, it kind of is. ALLOW FILTERING allows to execute some queries that couldn't be otherwise, but not everything. Again, things that are not supported are not mainly for implementation reasons, nothing more, and that may/will change in the future. That said, I'm not saying documentation cannot be improved (though I'm not sure having the doc saying this doesn't work would be a lot more helpful than trying it and having the implementation saying this doesn't work). -- Sylvain Thanks, Jens On Tue, Aug 5, 2014 at 8:11 PM, Sávio S. Teles de Oliveira savio.te...@cuia.com.br wrote: You need to create an index on attribute *c.* 2014-08-05 9:24 GMT-03:00 Jens Rantil jens.ran...@tink.se: Hi, I'm having an issue with ALLOW FILTERING with Cassandra 2.0.8. See a minimal example here: https://gist.github.com/JensRantil/ec43622c26acb56e5bc9 I expect the second last to fail, but the last query to return a single row. In particular I expect the last SELECT to first select using the clustering primary id and then do filtering. I've been reading https://cassandra.apache.org/doc/cql3/CQL.html#selectStmt ALLOW FILTERING and can't wrap my head around why this won't work. Could anyone clarify this for me? Thanks, Jens -- Atenciosamente, Sávio S. Teles de Oliveira voice: +55 62 9136 6996 http://br.linkedin.com/in/savioteles Mestrando em Ciências da Computação - UFG Arquiteto de Software CUIA Internet Brasil
Re: Issue with ALLOW FILTERING
Sylvain, Your answer was what I was hoping for - that means it's not impossible to solve ;) I'll keep an eye on the issue and in case I have the time I will dig into some code. Thanks, Jens On Wed, Aug 6, 2014 at 10:03 AM, Sylvain Lebresne sylv...@datastax.com wrote: On Wed, Aug 6, 2014 at 9:41 AM, Jens Rantil jens.ran...@tink.se wrote I'm struggling to see any reason for it not being supported. The time to implement it, plus a bunch of internal implementation reasons that makes it not as trivial to support as you seem to suggest it is (of course, this is open source, you are welcome to have a look if that's a particular itch you want to scratch; there is even a JIRA ticket: https://issues.apache.org/jira/browse/CASSANDRA-6377). Or is it considered implementation specific under what circumstances ALLOW FILTERING can be used? Currently, it kind of is. ALLOW FILTERING allows to execute some queries that couldn't be otherwise, but not everything. Again, things that are not supported are not mainly for implementation reasons, nothing more, and that may/will change in the future. That said, I'm not saying documentation cannot be improved (though I'm not sure having the doc saying this doesn't work would be a lot more helpful than trying it and having the implementation saying this doesn't work). -- Sylvain Thanks, Jens On Tue, Aug 5, 2014 at 8:11 PM, Sávio S. Teles de Oliveira savio.te...@cuia.com.br wrote: You need to create an index on attribute *c.* 2014-08-05 9:24 GMT-03:00 Jens Rantil jens.ran...@tink.se: Hi, I'm having an issue with ALLOW FILTERING with Cassandra 2.0.8. See a minimal example here: https://gist.github.com/JensRantil/ec43622c26acb56e5bc9 I expect the second last to fail, but the last query to return a single row. In particular I expect the last SELECT to first select using the clustering primary id and then do filtering. I've been reading https://cassandra.apache.org/doc/cql3/CQL.html#selectStmt ALLOW FILTERING and can't wrap my head around why this won't work. Could anyone clarify this for me? Thanks, Jens -- Atenciosamente, Sávio S. Teles de Oliveira voice: +55 62 9136 6996 http://br.linkedin.com/in/savioteles Mestrando em Ciências da Computação - UFG Arquiteto de Software CUIA Internet Brasil
Re: Issue with ALLOW FILTERING
On Wed, Aug 6, 2014 at 1:46 AM, Jens Rantil jens.ran...@tink.se wrote: Your answer was what I was hoping for - that means it's not impossible to solve ;) I'll keep an eye on the issue and in case I have the time I will dig into some code. Just have to mention here that : ALLOW FILTERING should be renamed PROBABLY TIMEOUT in order to properly describe its typical performance. If you find yourself having to use ALLOW FILTERING, it is possible you are Doing It Wrong.. :D =Rob
Issue with ALLOW FILTERING
Hi, I'm having an issue with ALLOW FILTERING with Cassandra 2.0.8. See a minimal example here: https://gist.github.com/JensRantil/ec43622c26acb56e5bc9 I expect the second last to fail, but the last query to return a single row. In particular I expect the last SELECT to first select using the clustering primary id and then do filtering. I've been reading https://cassandra.apache.org/doc/cql3/CQL.html#selectStmt ALLOW FILTERING and can't wrap my head around why this won't work. Could anyone clarify this for me? Thanks, Jens
Re: Issue with ALLOW FILTERING
You need to create an index on attribute *c.* 2014-08-05 9:24 GMT-03:00 Jens Rantil jens.ran...@tink.se: Hi, I'm having an issue with ALLOW FILTERING with Cassandra 2.0.8. See a minimal example here: https://gist.github.com/JensRantil/ec43622c26acb56e5bc9 I expect the second last to fail, but the last query to return a single row. In particular I expect the last SELECT to first select using the clustering primary id and then do filtering. I've been reading https://cassandra.apache.org/doc/cql3/CQL.html#selectStmt ALLOW FILTERING and can't wrap my head around why this won't work. Could anyone clarify this for me? Thanks, Jens -- Atenciosamente, Sávio S. Teles de Oliveira voice: +55 62 9136 6996 http://br.linkedin.com/in/savioteles Mestrando em Ciências da Computação - UFG Arquiteto de Software CUIA Internet Brasil
