Cassandra Time-Series data modelling

问题

I've been working on a data model for an analytics system for a little while now, but I just can't seem to get the right setup for my primary keys. I've watched a bunch of videos (https://www.youtube.com/watch?v=UP74jC1kM3w&list=PLqcm6qE9lgKJoSWKYWHWhrVupRbS8mmDA&index=9) to gain some learnings about best practises, especially concerning time-series data.

Regarding PRIMARY KEYS, I can't seem to get the right balance so that I can query the way I need to.

Here is my data model so far:

CREATE TABLE eventPropertyCountsByDay (
    user_id int,
    event_type varchar,
    property varchar,
    value varchar,
    date_to_day varchar,
    count counter,
    PRIMARY KEY ((event_type, user_id), date_to_day, property, value)
) WITH CLUSTERING ORDER BY (date_to_day DESC, property DESC, value DESC);

I am storing events in another table and event properties in this table (column family).

I need to be able to query according to the user id, with an IN query to get records for multiple users at once, but I also need to query on the property and value fields, as well as specifying a date range.

Here is an example of the query I'm trying to achieve:

SELECT * FROM eventPropertyCountsByWeek 
WHERE event_type = 'some_event' 
AND date_to_day > '2014-09-24'
AND user_id IN (123, 456) 
AND property = 'property_name' 
AND value = 'property_value'

How can I accomplish this sort of query? What kind of other column families might I need to introduce to break it down?

回答1:

Try this:

CREATE TABLE eventPropertyCountsByDay (
  user_id int,
  event_type varchar,
  property varchar,
  value varchar,
  date_to_day int, // day number
  count counter,
  PRIMARY KEY ((event_type, user_id), property, value, date_to_day)
) WITH CLUSTERING ORDER BY (property DESC, value DESC, date_to_day DESC);

I moved date_to_day at the end of clustering key to make it usable for range queries with fixed property and value.

Data updating query:

update eventPropertyCountsByDay set count = count + 1 where 
  user_id=1 and 
  event_type='log' and 
  property='prop1' and 
  value='val1' and 
  date_to_day=54321;

Select query:

select * from eventPropertyCountsByDay 
  where event_type='log' and 
    user_id=1 and 
    property='prop1' and
    value='val1' and 
    date_to_day > 54300;

 event_type | user_id | property | value | date_to_day | count
------------+---------+----------+-------+-------------+-------
        log |       1 |    prop1 |  val1 |       54323 |     2
        log |       1 |    prop1 |  val1 |       54321 |     1

来源：https://stackoverflow.com/questions/26009975/cassandra-time-series-data-modelling