CF ADD (error) Maximum expansions reached

[vansenic]

127.0.0.1:6379> CF.ADD zelnic_filter_detail d04f44de11aa8a084d7c0b37d434d59a
(error) Maximum expansions reached
127.0.0.1:6379> CF.INFO zelnic_filter_detail
 1) Size
 2) (integer) 33320
 3) Number of buckets
 4) (integer) 512
 5) Number of filters
 6) (integer) 32
 7) Number of items inserted
 8) (integer) 29337
 9) Number of items deleted
10) (integer) 1
11) Bucket size
12) (integer) 2
13) Expansion rate
14) (integer) 1
15) Max iterations
16) (integer) 20

How to fix this "Maximum expansions reached" error?

[gkorland]

How did you create the filter?
Did you check https://redis.io/commands/cf.reserve/?

[ashtul]

@vansenic the max expansion is in place since with every new filter, you add an error rate to your filter. At some point, it does not make sense to have the filter anymore.

It seems like your filter (or some of your filters) has a high rate of expansion. In this case, the recommendation is to use the EXPANSION expansion variable of 2 or even 4 with the CF.RESERVE command. Additional filters will be twice as large as the previous filter, which is a good fit in cases where filters are expected to grow by a significant amount (or when the final size is unknown when the filter is being created).