Hi guys,
I'm a cassandra noob who have recently inherited an 8+ year old cassandra 1.2.19 cluster, which needs upgrading. However, at the moment I'm taking some time to read cassandra docs to get myself acquainted with the inner workings of it and playing around.
My question is about querying (select *) one of the tables, which fails. I know that I should rather be using predicate filters with partitioning and clustering columns but I don't have access to the frontend tornado web server accessing the cassandra db plus I'm just testing waters to figure out what is and is not possible with this version of cassandra. Details as follows -
KEYSPACE -
CREATE KEYSPACE bigbox WITH replication = { 'class': 'SimpleStrategy', 'replication_factor': '3' };
TABLE -
CREATE TABLE "Databases" (
"KEY" blob,
column1 ascii,
value blob,
PRIMARY KEY ("KEY", column1))
WITH COMPACT STORAGE AND
bloom_filter_fp_chance=0.010000
AND caching='ROWS_ONLY'
AND comment=''
AND dclocal_read_repair_chance=0.000000
AND gc_grace_seconds=864000
AND read_repair_chance=1.000000
AND replicate_on_write='false'
AND compaction={'class': 'SizeTieredCompactionStrategy'}
AND compression={'chunk_length_kb': '64', 'sstable_compression': 'SnappyCompressor'};
However when I try to do a select * through the python datatax cassandra driver I get the following error -
cassandra.cluster.NoHostAvailable: ('Unable to complete the operation against any hosts', {<Host: 192.168.114.84:9042 datacenter1>: ConnectionException('Host has been marked down or removed'), <Host: 192.168.114.82:9042 datacenter1>: <Error from server: code=0000 [Server error] message="java.lang.UnsupportedOperationException: This operation is not supported for Super Columns.">, <Host: 192.168.114.81:9042 datacenter1>: <Error from server: code=0000 [Server error] message="java.lang.UnsupportedOperationException: This operation is not supported for Super Columns.">, <Host: 192.168.114.83:9042 datacenter1>: <Error from server: code=0000 [Server error] message="java.lang.UnsupportedOperationException: This operation is not supported for Super Columns.">})
Here is the relevant python code snippet - python 3.8.2, latest datastax cassandra driver
log.info("setting keyspace...")
session.set_keyspace(KEYSPACE)
query = 'SELECT value FROM "{0}"'.format(TABLE)
statement = SimpleStatement(query, fetch_size=10)
If I use a single column like column1 - 'select column1 from "Databases"' - I get results.
* can anyone let me know what *might* be going wrong in here?
* and is there a way I can get around this problem?
Thanks in advance!
