yifan-c commented on code in PR #4399: URL: https://github.com/apache/cassandra/pull/4399#discussion_r2414966140
########## conf/cassandra.yaml: ########## @@ -617,6 +617,54 @@ counter_cache_save_period: 7200s # Disabled by default, meaning all keys are going to be saved # counter_cache_keys_to_save: 100 +# Dictionary compression settings for ZSTD dictionary-based compression +# These settings control the automatic training and caching of compression dictionaries +# for tables that use ZSTD dictionary compression. + +# How often to refresh compression dictionaries across the cluster. +# During refresh, nodes will check for newer dictionary versions and update their caches. +# Min unit: s +compression_dictionary_refresh_interval: 3600s + +# Initial delay before starting the first dictionary refresh cycle after node startup. +# This prevents all nodes from refreshing simultaneously when the cluster starts. +# Min unit: s +compression_dictionary_refresh_initial_delay: 10s + +# Maximum number of compression dictionaries to cache per table. +# Each table using dictionary compression can have multiple dictionaries cached +# (current version plus recently used versions for reading older SSTables). +compression_dictionary_cache_size: 10 + +# How long to keep compression dictionaries in the cache before they expire. +# Expired dictionaries will be removed from memory but can be reloaded if needed. +# Min unit: s +compression_dictionary_cache_expire: 3600s Review Comment: `compression_dictionary_cache_expire` and `compression_dictionary_refresh_interval` are not strongly connected, since they apply to different components. Cache entry expiry is renewed on every access. Meanwhile, `compression_dictionary_refresh_interval` only defines how frequent to read from system table. If there is no access to the cache entry for 1 hour, it is evicted. The chance is low that the dictionary is wanted right after eviction. Even in such scenario, the cache entry is again populated from compressionInfo or system table. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
