Re:What every software engineer should know about Apache Kafka
by 411111111111111 on Monday May 18, 2020 @03:44PM
(#23227442)
haha, yes - thats a real possibility.
cassandra is at its heart a key-value store. for every queryable field, you need to create a new in-place copy of the data. so you're basically saving the data n-times, for each way you wish to query the data.
if you however try to query on a field which hasn't been marked as query-able, the cluster will have to basically select everything in the table and do a for loop to filter for the 'where' clause :-)
But i haven't used in production yet, so you've got more experience then i do
I'm referring to "Cannot execute this query as it might involve data filtering and thus may have unpredictable performance. If you want to execute this query despite the performance unpredictability, use ALLOW FILTERING"
> It's just not as efficient.
That's what I thought, too, so I "allowed filtering". And crashed the database. (Apparently the correct solution here is to use Spark).