In a CQL 3 table the only **column** names are the ones defined in the table,
in the example below there are three column names.
CREATE TABLE keyspace.widerow (
row_key text,
wide_row_column text,
data_column text,
PRIMARY KEY (row_key, wide_row_column));
Check out, for example,
To: Cassandra User
Subject: Re: CQL 3 and wide rows
In a CQL 3 table the only **column** names are the ones defined in the table,
in the example below there are three column names.
CREATE TABLE keyspace.widerow (
row_key text,
wide_row_column text,
data_column text
primary key”.
-- Jack Krupansky
From: Aaron Morton
Sent: Tuesday, May 20, 2014 3:06 AM
To: Cassandra User
Subject: Re: CQL 3 and wide rows
In a CQL 3 table the only **column** names are the ones defined in the table,
in the example below there are three column names.
CREATE TABLE
Hi Aron,
Thanks for the answer!
Lest consider such CLI code:
for(int i = 0 ; i 10_000_000 ; i++) {
set[‘rowKey1’][‘myCol::i’] = UUID.randomUUID();
}
The code above will create single row, that contains 10^6 columns sorted by
‘i’. This will work fine, and this is the wide row to my
Something like this might work:
cqlsh:my_keyspace CREATE TABLE my_widerow (
... id text,
... my_col timeuuid,
... PRIMARY KEY (id, my_col)
... ) WITH caching='KEYS_ONLY' AND
... compaction={'class':
Thank you Nate - now I understand it ! This is real improvement when compared
to CLI :)
Regards,
Maciej
On 20 May 2014, at 17:16, Nate McCall n...@thelastpickle.com wrote:
Something like this might work:
cqlsh:my_keyspace CREATE TABLE my_widerow (
... id text,
Maciej,
In CQL3 wide rows are expected to be created using clustering columns. So
while the schema will have a relatively smaller number of named columns, the
effect is a wide row. For example:
CREATE TABLE keyspace.widerow (
row_key text,
wide_row_column text,
data_column text,
You might want to review this blog post on supporting dynamic columns in CQL3,
which points out that “the way to model dynamic cells in CQL is with a compound
primary key.”
See:
http://www.datastax.com/dev/blog/does-cql-support-dynamic-columns-wide-rows
-- Jack Krupansky
From: Maciej Miklas
Hallo Jack,
You have given a perfect example for wide row. Each reading from sensor
creates new column within a row. It was also possible with Hector/CLI to have
millions of columns within a single row. According to this page
http://wiki.apache.org/cassandra/CassandraLimitations single row
Hi James,
Clustering is based on rows. I think that you meant not clustering columns, but
compound columns. Still all columns belong to single table and are stored
within single folder on one computer. And it looks to me (but I’am not sure)
that CQL 3 driver loads all column names into memory
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