Cassandra: how to initialize the counter column with value? - cassandra

Question

I have to benchmark Cassandra with the Facebook Linkbench. There are two phase during the Benchmark, the load and the request phase.
in the Load Phase, Linkbench fill the cassandra tables : nodes, links and counts (for links counting) with default values(graph data).
the count table looks like this:
keyspace.counttable (
link_id bigint,
link_type bigint,
time bigint,
version bigint,
count counter,
PRIMARY KEY (link_id, link_type, time, version)
my question is how to insert the default counter values (before incrementing and decrementing the counter in the Linkbench request phase) ?
If it isn't possible to do that with cassandra, how should i increment/decrement a bigint variable (instead of counter variable)
Any suggest and comments? Thanks a lot.

Answer 1

The default value is zero. Given
create table counttable (
link_id bigint,
link_type bigint,
time bigint,
version bigint,
count counter,
PRIMARY KEY (link_id, link_type, time, version)
);
and
update counttable set count = count + 1 where link_id = 1 and link_type = 1 and time = 1 and version = 1;
We see that the value of count is now 1.
select * from counttable ;
link_id | link_type | time | version | count
---------+-----------+------+---------+-------
1 | 1 | 1 | 1 | 1
(1 rows)
So, if we want to set it to some other value we can:
update counttable set count = count + 500 where link_id = 1 and link_type = 1 and time = 1 and version = 2;
select * from counttable ;
link_id | link_type | time | version | count
---------+-----------+------+---------+-------
1 | 1 | 1 | 1 | 1
1 | 1 | 1 | 2 | 500
(2 rows)

Answer 2

There is no elegant way to initialize a counter column with a non-zero value. The only operation you can do on a counter field is increment/decrement. I recommend to keep the offset (e.g. the your intended initial value) in a different column, and simply add the two values in your client application.

Answer 3

Thank you for the Answers. I implemented the following solution to initialize the counter Field.
as the initial and default value of the counter Field is 0 ,i incremented it with my default value. it looks like Don Branson solution but with only one column:
create table counttable (
link_id bigint,
link_type bigint,
count counter,
PRIMARY KEY (link_id, link_type)
);
i set the value with this statement (during the load phase):
update counttable set count = count + myValue where link_id = 1 and link_type = 1;
select * from counttable ;
link_id | link_type | count
---------+-----------+--------
1 | 1 | myValue (added to 0)
(1 row)