Thank you Eric,
I think we have a limited number of dynamically named columns but I'm
not inclined to have them added in the schema.
I have just managed to do what I want with the schema below. But It cost
me my secondary index on eventId. Because eventId is a clustering_key
it's not yet supported.
(Bad Request: Secondary index on CLUSTERING_KEY column name is not yet
supported for compact table)
Of course, I'm not sure how this will effect our archaic application so
I have to test hard before applying this change.
CREATE TABLE "EventKeys" (
key ascii,
name ascii,
value ascii,
PRIMARY KEY (key,"name")
)
Select * from EventKeys where key='b5f0d4be-c0fc-4dc4-8e38-0a00e4552866';
key | name | value
--------------------------------------+------------+--------------------------
b5f0d4be-c0fc-4dc4-8e38-0a00e4552866 | actionId |
080abda2-3623-4a98-a84a-d33b6aecbe99
b5f0d4be-c0fc-4dc4-8e38-0a00e4552866 | code | var x = .....\n
b5f0d4be-c0fc-4dc4-8e38-0a00e4552866 | eventId |
ce3b0c03-dcce-4522-a35a-864909cb024f
On 10/15/2015 06:09 PM, Eric Stevens wrote:
If the columns are not dynamically named (as in "actionId" and "code")
you should be able to add that to your CQL table definition with ALTER
TABLE, and those columns should be available in the query results.
If the columns /are/ dynamically named, and you can't reasonably add
every option to the CQL definition, your job gets a lot harder. If
you're using composite names, there might be some hope if you happen
to conform to the same standard as CQL collections (not impossible,
but probably not super likely). You can create a test table with one
of each collection type, insert a record, then look at the Thrift to
see how those map.
If your dynamically named columns are string concatenation or some
other custom serialization format, then your only hope is basically a
data migration from your thrift format to your CQL format. You should
be able to accomplish all the same business functionality using CQL,
but you might not be able to create a CQL schema that maps exactly to
the data at rest for your historic schema.
On Thu, Oct 15, 2015 at 8:54 AM Onur Yalazı <onur.yal...@8digits.com
<mailto:onur.yal...@8digits.com>> wrote:
Hello,
I have a cassandra cluster from pre-cql era and I am having problems
accessing data via cqlsh.
As you can see below, I can not reach dynamic columns via cqlsh
but they
are accessible via cassandra-cli.
How can I make the data shown on cqlsh?
cqlsh:automation> select * from "EventKeys" where
key='b5f0d4be-c0fc-4dc4-8e38-0a00e4552866' ;
key |eventId
--------------------------------------+--------------------------------------
b5f0d4be-c0fc-4dc4-8e38-0a00e4552866 |
ce3b0c03-dcce-4522-a35a-864909cb024f
(1 rows)
[default@keyspace] get
EventKeys['b5f0d4be-c0fc-4dc4-8e38-0a00e4552866'];
=> (name=actionId, value=3038...............643333623661656362653939,
timestamp=1431608711629002)
=> (name=code, b0a..........0a0a, timestamp=1431608711629003)
=> (name=eventId, value=ce3b0c03-dcce-4522-a35a-864909cb024f,
timestamp=1431608711629000)
Returned 3 results.
ColumnFamily Description:
ColumnFamily: EventKeys
Key Validation Class: org.apache.cassandra.db.marshal.AsciiType
Default column value validator:
org.apache.cassandra.db.marshal.BytesType
Cells sorted by: org.apache.cassandra.db.marshal.UTF8Type
GC grace seconds: 864000
Compaction min/max thresholds: 4/32
Read repair chance: 0.1
DC Local Read repair chance: 0.0
Populate IO Cache on flush: false
Replicate on write: true
Caching: KEYS_ONLY
Default time to live: 0
Bloom Filter FP chance: 0.01
Index interval: 128
Speculative Retry: 99.0PERCENTILE
Built indexes: [EventKeys.eventkeys_eventid_idx]
Column Metadata:
Column Name: scenarioId
Validation Class: org.apache.cassandra.db.marshal.AsciiType
Index Name: eventkeys_eventid_idx
Index Type: KEYS
Index Options: {}
Compaction Strategy:
org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy
Compaction Strategy Options:
min_threshold: 4
max_threshold: 32
Compression Options:
sstable_compression:
org.apache.cassandra.io
<http://org.apache.cassandra.io>.compress.SnappyCompressor
CQL Desc of the table:
CREATE TABLE "EventKeys" (
key ascii,
"eventId" ascii,
PRIMARY KEY (key)
) WITH COMPACT STORAGE AND
bloom_filter_fp_chance=0.010000 AND
caching='KEYS_ONLY' AND
comment='' AND
dclocal_read_repair_chance=0.000000 AND
gc_grace_seconds=864000 AND
index_interval=128 AND
read_repair_chance=0.100000 AND
replicate_on_write='true' AND
populate_io_cache_on_flush='false' AND
default_time_to_live=0 AND
speculative_retry='99.0PERCENTILE' AND
memtable_flush_period_in_ms=0 AND
compaction={'min_threshold': '4', 'class':
'SizeTieredCompactionStrategy', 'max_threshold': '32'} AND
compression={'sstable_compression': 'SnappyCompressor'};
CREATE INDEX eventkeys_eventid_idx ON "EventKeys" ("eventId");
