CODEWITHSUNDEEP
cassandra
CordlessWool
CordlessWool

Reputation: 1530

remove specified ttl in cassandra

I read about updating ttl and that it is only possible by updating row. But I want to remove ttl. I fear it is the same process, but I did not found any information about it. Is there a way to remove ttl without updating all rows?

What I do, is saving user information with ttl when user is registrating. So if the user do not validate his/her mail address the entry will automaticly delete.

Upvotes: 0

Views: 1602

Answers (1)

flavian
flavian

Reputation: 28511

Here's an excerpt from the official docs here.

If you want to change the TTL of expiring data, you have to re-insert the data with a new TTL. In Cassandra, the insertion of data is actually an insertion or update operation, depending on whether or not a previous version of the data exists.

TTL data has a precision of one second, as calculated on the server. Therefore, a very small TTL probably does not make much sense. Moreover, the clocks on the servers should be synchronized; otherwise reduced precision could be observed because the expiration time is computed on the primary host that receives the initial insertion but is then interpreted by other hosts on the cluster.

This is slightly unpleasant in practice, but it's relatively easy to build a very simple migration tool, you would simply iterate through the entire table and re-insert all the records with a new TTL in another table.

If computationally/storage-wise you can afford to do this, it's probably a more compelling idea to store the records twice, once with TTL and once without, simply to go around the limitation: you cannot cancel or change the TTL in Cassandra.

Upvotes: 1

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