If this is a standard column family, not a CQL3 table, then using CQL3 will
not give you the results you expect.
>From cassandra-cli, let's set up some test data:
[default@unknown] create keyspace test;
[default@unknown] use test;
[default@test] create column family test;
[default@test] set test['a1']['c1'] = 'a1c1';
[default@test] set test['a1']['c2'] = 'a1c2';
[default@test] set test['a2']['c1'] = 'a2c1';
[default@test] set test['a2']['c2'] = 'a2c2';
Two rows with two columns each, right? Not as far as CQL3 is concerned:
cqlsh> use test;
cqlsh:test> select * from test;
key | column1 | value
-----+---------+--------
a2 | 0xc1 | 0xa2c1
a2 | 0xc2 | 0xa2c2
a1 | 0xc1 | 0xa1c1
a1 | 0xc2 | 0xa1c2
Basically for CQL3, without the additional metadata and enforcement that is
established by having created the column family as a CQL3 table, CQL will
treat each key/column pair as a separate row for CQL purposes. This is
most likely at least in part due to the fact that CQL3 tables *cannot have
arbitrary columns *like standard column families can. It wouldn't know
what columns are available for display. This also exposes some of the
underlying structure behind CQL3 tables.
CQL 3 is not reverse compatible with CQL 2 for most things. If you cannot
migrate your data to a CQL3 table.
The equivalent structure in CQL3 tables
cqlsh:test> create table test3 (key text PRIMARY KEY, c1 text, c2 text);
cqlsh:test> INSERT INTO test3(key, c1, c2) VALUES ('a1', 'a1c1', 'a1c2');
cqlsh:test> INSERT INTO test3(key, c1, c2) VALUES ('a2', 'a2c1', 'a2c2');
cqlsh:test> select * from test3;
key | c1 | c2
-----+------+------
a2 | a2c1 | a2c2
a1 | a1c1 | a1c2
This comes with many important restrictions, one of which as mentioned is
that you cannot have arbitrary columns in a CQL3 table, just like you
cannot in a traditional relational database. Likewise you cannot use
traditional approaches to populating data into a CQL3 table:
[default@test] get test3['a1'];
test3 not found in current keyspace.
[default@test] set test3['a3']['c1'] = 'a3c1';
test3 not found in current keyspace.
[default@test] describe test3;
WARNING: CQL3 tables are intentionally omitted from 'describe' output.
On Tue, Jun 4, 2013 at 12:56 PM, ekaqu something <ekaqu1...@gmail.com>wrote:
> I run a 1.1 cluster and currently testing out a 1.2 cluster. I have
> noticed that with 1.2 it switched to CQL3 which is acting differently than
> I would expect. When I do "select key from \"cf\";" I get many many
> duplicate keys. When I did the same with CQL 2 I only get the keys
> defined. This seems to also be the case for count(*), in cql2 it would
> return the number of keys i have, in 3 it returns way more than i really
> have.
>
> $ cqlsh `hostname` <<EOF
> use keyspace;
> select count(*) from "cf";
> EOF
>
>
> count
> -------
> 10000
>
> Default LIMIT of 10000 was used. Specify your own LIMIT clause to get more
> results.
>
> $ cqlsh `hostname` -3 <<EOF
> use keyspace;
> select count(*) from "cf";
> EOF
>
>
> count
> -------
> 10000
>
> Default LIMIT of 10000 was used. Specify your own LIMIT clause to get more
> results.
>
>
> $ cqlsh `hostname` -2 <<EOF
> use keyspace;
> select count(*) from cf;
> EOF
>
>
> count
> -------
> 1934
>
> 1934 rows have really been inserted. Is there something up with cql3 or is
> there something else going on?
>
> Thanks for your time reading this email.
>
