From reports on this mailing list, I do not allow materialized views.
Sean Durity From: Reid Pinchback <rpinchb...@tripadvisor.com> Sent: Thursday, February 6, 2020 4:10 PM To: user@cassandra.apache.org Subject: Re: [EXTERNAL] Re: Running select against cassandra Abdul, When in doubt, have a query model that immediately feeds you exactly what you are looking for. That’s kind of the data model philosophy that you want to shoot for as much as feasible with C*. The point of Sean’s table isn’t the similarity to yours, it is how he has it keyed because it suits a partition structure much better aligned with what you want to request. So I’d say yes, if a materialized view is how you want to achieve a denormalized state where the query model directly supports giving you want you want to query for, that sounds like an appropriate option to consider. You might want a composite partition key for having an efficient selection of narrow time ranges. From: Abdul Patel <abd786...@gmail.com<mailto:abd786...@gmail.com>> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Date: Thursday, February 6, 2020 at 2:42 PM To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Subject: Re: [EXTERNAL] Re: Running select against cassandra Message from External Sender this is the schema similar to what we have , they want to get user connected - concurrent count for every say 1-5 minutes. i am thinking will simple select will have performance issue or we can go for materialized views ? CREATE TABLE usr_session ( userid bigint, session_usr text, last_access_time timestamp, login_time timestamp, status int, PRIMARY KEY (userid, session_usr) ) WITH CLUSTERING ORDER BY (session_usr ASC) On Thu, Feb 6, 2020 at 2:09 PM Durity, Sean R <sean_r_dur...@homedepot.com<mailto:sean_r_dur...@homedepot.com>> wrote: Do you only need the current count or do you want to keep the historical counts also? By active users, does that mean some kind of user that the application tracks (as opposed to the Cassandra user connected to the cluster)? I would consider a table like this for tracking active users through time: Create table users_by_day ( app_date date, hour integer, minute integer, user_count integer, longest_login_user text, longest_login_seconds integer, last_login datetime, last_login_user text ) primary key (app_date, hour, minute); Then, your reporting can easily select full days or a specific, one-minute slice. Of course, the app would need to have a timer and write out the data. I would also suggest a TTL on the data so that you only keep what you need (a week, a year, whatever). Of course, if your reporting requires different granularities, you could consider a different time bucket for the table (by hour, by week, etc.) Sean Durity – Staff Systems Engineer, Cassandra From: Abdul Patel <abd786...@gmail.com<mailto:abd786...@gmail.com>> Sent: Thursday, February 6, 2020 1:54 PM To: user@cassandra.apache.org<mailto:user@cassandra.apache.org> Subject: [EXTERNAL] Re: Running select against cassandra Its sort of user connected, app team needa number of active users connected say every 1 to 5 mins. The timeout at app end is 120ms. On Thursday, February 6, 2020, Michael Shuler <mich...@pbandjelly.org<mailto:mich...@pbandjelly.org>> wrote: You'll have to be more specific. What is your table schema and what is the SELECT query? What is the normal response time? As a basic guide for your general question, if the query is something sort of irrelevant that should be stored some other way, like a total row count, or most any SELECT that requires ALLOW FILTERING, you're doing it wrong and should re-evaluate your data model. 1 query per minute is a minuscule fraction of the basic capacity of queries per minute that a Cassandra cluster should be able to handle with good data modeling and table-relevant query. All depends on the data model and query. Michael On 2/6/20 12:20 PM, Abdul Patel wrote: Hi, Is it advisable to run select query to fetch every minute to grab data from cassandra for reporting purpose, if no then whats the alternative? --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org<mailto:user-unsubscr...@cassandra.apache.org> For additional commands, e-mail: user-h...@cassandra.apache.org<mailto:user-h...@cassandra.apache.org> ________________________________ The information in this Internet Email is confidential and may be legally privileged. It is intended solely for the addressee. Access to this Email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. 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