CODEWITHSUNDEEP
cassandrattl
Saeid
Saeid

Reputation: 493

How to delete Counter columns in Cassandra?

I know Cassandra rejects TTL for counter type. So, what's the best practice to delete old counters? e.g. old view counters.

Should I create cron jobs for deleting old counters?

Upvotes: 2

Views: 1433

Answers (2)

Desert Ice
Desert Ice

Reputation: 4600

Don't worry about handling this case yourself cassandra will do it for you, you can just delete it and be on your way.

General guidelines in cases like this: Make sure to run compaction on a regular basis and run repairs once every "gc_grace_seconds" to avoid increased disk usage and distributed deletes.

Upvotes: 0

Jim Meyer
Jim Meyer

Reputation: 9475

It's probably not a good practice to delete individual clustered rows or partitions from a counter table, since the key you delete cannot be used again. That could give rise to bugs if the application tries to increment a counter in a deleted row, since the increment won't happen. If you use a unique key whenever you create a new counter, then maybe you could get away with it.

So a better approach may be to truncate or drop the entire table, so that afterwards you can re-use keys. To do this you'd need to separate your counters into multiple tables, such as one per month for example, so that you could truncate or drop an entire table when it was no longer relevant. You could have a cron job that runs periodically and drops the counter table from x months ago.

Upvotes: 4

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