In syslog-ng Store Box (SSB) Search > Logspaces > Customize columns > Available dynamic columns, there are many different dynamic columns to choose from in case of complex configurations and the list of available dynamic columns might take a long time to load.
However unused and not needed dynamic columns cannot be deleted from the available dynamic columns.
Dynamic columns are created from structured data parameters in log messages stored on SSB. Structured data parameters are detected and added to the list of customizable columns automatically. Since dynamic columns are stored in the logstore itself, they remain in the available columns list as long as the logstore exists within SSB.
Step 1: Delete the old logstores with the old and already unnecessary keys in SSB's GUI (Log > Logspaces)
# rm -f /opt/ssb/var/persistent_storage/logspace_query_cache_xxxxxx.serialized