Did you try to explore CQL3 collection support for the same? You can definitely save on number of rows with that.
Point which i am trying to make out is, you can achieve it via CQL3 ( Jonathan's blog : http://www.datastax.com/dev/blog/does-cql-support-dynamic-columns-wide-rows) I agree with you that still thrift may have some valid points to prove, but considering latest development around new Cassandra features, i think CQL3 is the path to follow. -Vivek On Sat, Aug 31, 2013 at 12:15 AM, Peter Lin <wool...@gmail.com> wrote: > > you could dynamically create new tables at runtime and insert rows into > the new table, but is that better than using thrift and putting it into a > regular dynamic column with the exact name type and value type? > > that would mean if there's 20 dynamic columns of different types, you'd > have to execute 21 queries to rebuild the data. That's basically the same > as using EVA tables in relational databases. > > Having used that approach in the past to build temporal databases, it > doesn't scale well. > > > > On Fri, Aug 30, 2013 at 2:40 PM, Vivek Mishra <mishra.v...@gmail.com>wrote: > >> create a column family as: >> >> create table dynamicTable(key text, nameAsDouble double, valueAsBlob >> blob); >> >> insert into dynamicTable(key, nameAsDouble, valueAsBlob) values ( "key", >> double(102.211), >> textAsBlob('valueInBytes'). >> >> Do you think, it will work in case column name are double? >> >> -Vivek >> >> >> On Sat, Aug 31, 2013 at 12:03 AM, Peter Lin <wool...@gmail.com> wrote: >> >>> >>> In the interest of education and discussion. >>> >>> I didn't mean to say CQL3 doesn't support dynamic columns. The example >>> from the page shows default type defined in the create statement. >>> >>> create column family data >>> with key_validation_class=Int32Type >>> and comparator=DateType >>> and default_validation_class=FloatType; >>> >>> >>> If I try to insert a dynamic column that uses double for column name and >>> string for column value, it will throw an error. The kind of use case I'm >>> talking about defines a minimum number of static columns. Most of the >>> columns that are added at runtime are different name and value type. This >>> is specific to my use case. >>> >>> Having said that, I believe it "would" be possible to provide that kind >>> of feature in CQL, but the trade off is it deviates from SQL. The grammar >>> would have to allow type declaration in the columns list and functions in >>> the values. Something like >>> >>> insert into mytable (KEY, doubleType(newcol1), string(newcol2)) values >>> ('abc123', "some string", double(102.211)) >>> >>> doubleType(newcol1) and string(newcol2) are dynamic columns. >>> >>> I know many people find thrift hard to grok and struggle with it, but >>> I'm a firm believer in taking time to learn. Every developer should take >>> time to read cassandra source code and the source code for the driver >>> they're using. >>> >>> >>> >>> On Fri, Aug 30, 2013 at 2:18 PM, Jonathan Ellis <jbel...@gmail.com>wrote: >>> >>>> >>>> http://www.datastax.com/dev/blog/does-cql-support-dynamic-columns-wide-rows >>>> >>>> >>>> On Fri, Aug 30, 2013 at 12:53 PM, Peter Lin <wool...@gmail.com> wrote: >>>> >>>>> >>>>> my bias perspective, I find the sweet spot is thrift for insert/update >>>>> and CQL for select queries. >>>>> >>>>> CQL is too limiting and negates the power of storing arbitrary data >>>>> types in dynamic columns. >>>>> >>>>> >>>>> On Fri, Aug 30, 2013 at 1:45 PM, Jon Haddad <j...@jonhaddad.com> wrote: >>>>> >>>>>> If you're going to work with CQL, work with CQL. If you're going to >>>>>> work with Thrift, work with Thrift. Don't mix. >>>>>> >>>>>> On Aug 30, 2013, at 10:38 AM, Vivek Mishra <mishra.v...@gmail.com> >>>>>> wrote: >>>>>> >>>>>> Hi, >>>>>> If i a create a table with CQL3 as >>>>>> >>>>>> create table user(user_id text PRIMARY KEY, first_name text, >>>>>> last_name text, emailid text); >>>>>> >>>>>> and create index as: >>>>>> create index on user(first_name); >>>>>> >>>>>> then inserted some data as: >>>>>> insert into user(user_id,first_name,last_name,"emailId") >>>>>> values('@mevivs','vivek','mishra','vivek.mis...@impetus.co.in'); >>>>>> >>>>>> >>>>>> Then if update same column family using Cassandra-cli as: >>>>>> >>>>>> update column family user with key_validation_class='UTF8Type' and >>>>>> column_metadata=[{column_name:last_name, validation_class:'UTF8Type', >>>>>> index_type:KEYS},{column_name:first_name, validation_class:'UTF8Type', >>>>>> index_type:KEYS}]; >>>>>> >>>>>> >>>>>> Now if i connect via cqlsh and explore user table, i can see column >>>>>> first_name,last_name are not part of table structure anymore. Here is the >>>>>> output: >>>>>> >>>>>> CREATE TABLE user ( >>>>>> key text PRIMARY KEY >>>>>> ) WITH >>>>>> 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 >>>>>> read_repair_chance=0.100000 AND >>>>>> replicate_on_write='true' AND >>>>>> populate_io_cache_on_flush='false' AND >>>>>> compaction={'class': 'SizeTieredCompactionStrategy'} AND >>>>>> compression={'sstable_compression': 'SnappyCompressor'}; >>>>>> >>>>>> cqlsh:cql3usage> select * from user; >>>>>> >>>>>> user_id >>>>>> --------- >>>>>> @mevivs >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> I understand that, CQL3 and thrift interoperability is an issue. But >>>>>> this looks to me a very basic scenario. >>>>>> >>>>>> >>>>>> >>>>>> Any suggestions? Or If anybody can explain a reason behind this? >>>>>> >>>>>> -Vivek >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >>>> >>>> >>>> -- >>>> Jonathan Ellis >>>> Project Chair, Apache Cassandra >>>> co-founder, http://www.datastax.com >>>> @spyced >>>> >>> >>> >> >
