Thanks for all the explanations. It's odd, that pure range queries are not supported at this time. But I think I'll find a solution for my problem.
Greetings -------- Original-Nachricht -------- > Datum: Sun, 14 Aug 2011 07:09:55 -0700 > Von: Jason Rutherglen <jason.rutherg...@gmail.com> > An: user@cassandra.apache.org > Betreff: Re: CQL: No indexed column error when < or <= in WHERE clause > This will be fully solved with CASSANDRA-2915 which will use Lucene as > a the secondary index type implementation. Lucene has extremely fast > range queries built in. > > On Sun, Aug 14, 2011 at 6:38 AM, Sal Fuentes <fuente...@gmail.com> wrote: > > The important piece that is mentioned in Jonathan's link is this: > > "One consequence of the KEYS index type being more like a hash index > than a > > btree is shown here: even though birth_date is indexed, Cassandra > couldn’t > > perform the range query “> 1970″ against it." > > hash index vs a btree index. Basically what this means is that these > > secondary indexes do not currently support queries of the type greater > than, > > less than on a single column. > > However, Cassandra will allow you to submit these types of queries when > you > > have multiple indexed columns; even though it may not be very efficient. > > "We can perform the range query now that the state column is also > indexed, > > so Cassandra can use the state predicate as the primary and filter on > the > > other with a nested loop." > > [default@demo] get users where birth_date = 1973; > > ------------------- > > RowKey: prothfuss > > => (column=birth_date, value=1973, timestamp=1313327531411000) > > => (column=full_name, value=Patrick Rothfuss, > timestamp=1313327526515000) > > 1 Row Returned. > > [default@demo] get users where birth_date > 1972; > > No indexed columns present in index clause with operator EQ > > [default@demo] get users where birth_date < 1974; > > No indexed columns present in index clause with operator EQ > > [default@demo] get users where birth_date >= 1973; > > No indexed columns present in index clause with operator EQ > > > > On Sun, Aug 14, 2011 at 6:11 AM, Martin von Zweigbergk > > <martin.von.zweigbe...@gmail.com> wrote: > >> > >> Hi Jens, > >> > >> I have never used CQL myself and I have barely used Cassandra, but I > >> think I've seen it mentioned before on this list that you need to use > >> compare for equality on at least one column (as indicated by "No > >> indexed columns present in by-columns clause with "equals" operator"). > >> The lookup will then be done based on that column and additional > >> filtering (such as for "less than") will be done on the result of the > >> first lookup, which can potentially be a large data set. You might > >> also want to redesign your data model to allow for a more efficient > >> lookup. > >> > >> Hope that helps (despite my lack of knowledge on the subject) > >> Martin > >> > >> On Sun, Aug 14, 2011 at 8:53 AM, Jens Hartung <ho...@gmx.de> wrote: > >> > I had indexed the number column in station column family. Do I also > have > >> > to index another column? > >> > > >> > What I'm wondering, when I type "get station where number = 8210;" > all > >> > works fine, but when I type "get station where number < 8210;" I'll > get > >> > mentioned exception. > >> > > >> > Is there something, that I misunderstand? > >> > > >> > -------- Original-Nachricht -------- > >> >> Datum: Sat, 13 Aug 2011 18:14:05 -0700 > >> >> Von: Jonathan Ellis <jbel...@gmail.com> > >> >> An: user@cassandra.apache.org > >> >> Betreff: Re: CQL: No indexed column error when < or <= in WHERE > clause > >> > > >> >> This is covered in > >> >> > >> >> > http://www.datastax.com/dev/blog/whats-new-cassandra-07-secondary-indexes > >> >> > >> >> On Sat, Aug 13, 2011 at 2:49 PM, Jens Hartung <ho...@gmx.de> wrote: > >> >> > Hi together, > >> >> > > >> >> > first, I'm using Cassandra Version 0.8.4 and access it via CQL > 1.0.3. > >> >> > > >> >> > When I select data from Cassandra with = in WHERE clause, > everything > >> >> works fine, but when using <= or < in WHERE clause, I always get > >> >> following > >> >> Exception: > >> >> > > >> >> > java.sql.SQLException: No indexed columns present in by-columns > >> >> > clause > >> >> with "equals" operator > >> >> > at > >> >> > >> >> > org.apache.cassandra.cql.jdbc.CassandraStatement.executeQuery(CassandraStatement.java:242) > >> >> > at > >> >> > >> >> > columnfamily.queries.CassandraQueries.singleColumnSelect(CassandraQueries.java:147) > >> >> > ... > >> >> > > >> >> > My select-statement: "SELECT number FROM station WHERE number <= > >> >> > 8210;" > >> >> > > >> >> > Output of describe keyspace (within cli): > >> >> > ColumnFamily: station > >> >> > Key Validation Class: > org.apache.cassandra.db.marshal.UTF8Type > >> >> > Default column value validator: > >> >> org.apache.cassandra.db.marshal.UTF8Type > >> >> > Columns sorted by: > org.apache.cassandra.db.marshal.UTF8Type > >> >> > Row cache size / save period in seconds: 0.0/0 > >> >> > Key cache size / save period in seconds: 200000.0/14400 > >> >> > Memtable thresholds: 0.2109375/1440/45 (millions of > >> >> ops/minutes/MB) > >> >> > GC grace seconds: 864000 > >> >> > Compaction min/max thresholds: 4/32 > >> >> > Read repair chance: 1.0 > >> >> > Replicate on write: true > >> >> > Built indexes: [station.station_number_idx] > >> >> > Column Metadata: > >> >> > [...] > >> >> > Column Name: number > >> >> > Validation Class: > org.apache.cassandra.db.marshal.LongType > >> >> > Index Name: station_number_idx > >> >> > Index Type: KEYS > >> >> > [...] > >> >> > > >> >> > Are the <, <=, >=, > operators not supported at this time? > >> >> > > >> >> > Greetings > >> >> > Jens > >> >> > -- > >> >> > NEU: FreePhone - 0ct/min Handyspartarif mit Geld-zurück-Garantie! > >> >> > Jetzt informieren: http://www.gmx.net/de/go/freephone > >> >> > > >> >> > >> >> > >> >> > >> >> -- > >> >> Jonathan Ellis > >> >> Project Chair, Apache Cassandra > >> >> co-founder of DataStax, the source for professional Cassandra > support > >> >> http://www.datastax.com > >> > > >> > -- > >> > NEU: FreePhone - 0ct/min Handyspartarif mit Geld-zurück-Garantie! > >> > Jetzt informieren: http://www.gmx.net/de/go/freephone > >> > > > > > > > > > -- > > Salvador Fuentes Jr. > > -- Empfehlen Sie GMX DSL Ihren Freunden und Bekannten und wir belohnen Sie mit bis zu 50,- Euro! https://freundschaftswerbung.gmx.de
