As an aside, if you're not putting a TTL on your data, it's a good idea to be proactive and use multiple tables. For example, one per month or year. This allows you the flexibility to delete your data by dropping old tables.
Storing old data in Cassandra is expensive. Once you get to a certain point it becomes far more cost effective to offload your old data to an object store and keep your Cassandra cluster to a minimum size. I gave a talk on this topic on my YT channel: https://www.youtube.com/live/Ysfi3V2KQtU Jon On Thu, May 23, 2024 at 7:35 AM Bowen Song via user < user@cassandra.apache.org> wrote: > As the log level name "DEBUG" suggested, these are debug messages, not > warnings. > > Is there any reason made you believe that these messages are warnings? > > > On 23/05/2024 11:10, Isaeed Mohanna wrote: > > Hi > > I have a big table (~220GB reported by used space live by tablestats) with > time series data that uses TWCS with the following settings > compaction = {'class': > 'org.apache.cassandra.db.compaction.TimeWindowCompactionStrategy', > 'compaction_window_size': '7', 'compaction_window_unit': 'DAYS', > 'max_threshold': '32', 'min_threshold': '4'} > > The table does not have a TTL configured since we need the data, it now > has ~450 sstables, I have had this setup for several years and so far I am > satisfied with the performance, we mostly read\write data from the previous > several months. Requests for earlier data occur but not in the quantities > and performance is less critical then. > > I have recently noticed reoccurring warning in the Cassandra log file and > I wanted to ask about their meaning and wither I need to do something about > it > > DEBUG [CompactionExecutor:356242] 2024-05-23 09:01:59,655 > TimeWindowCompactionStrategy.java:129 - TWCS skipping check for fully > expired SSTables > DEBUG [CompactionExecutor:356242] 2024-05-23 09:01:59,655 > TimeWindowCompactionStrategy.java:129 - TWCS skipping check for fully > expired SSTables > DEBUG [CompactionExecutor:356243] 2024-05-23 09:02:59,655 > TimeWindowCompactionStrategy.java:122 - TWCS expired check sufficiently far > in the past, checking for fully expired SSTables > DEBUG [CompactionExecutor:356243] 2024-05-23 09:02:59,658 > TimeWindowCompactionStrategy.java:122 - TWCS expired check sufficiently far > in the past, checking for fully expired SSTables > DEBUG [CompactionExecutor:356242] 2024-05-23 09:03:59,655 > TimeWindowCompactionStrategy.java:129 - TWCS skipping check for fully > expired SSTables > DEBUG [CompactionExecutor:356242] 2024-05-23 09:03:59,656 > TimeWindowCompactionStrategy.java:129 - TWCS skipping check for fully > expired SSTables > DEBUG [CompactionExecutor:356245] 2024-05-23 09:05:00,490 > TimeWindowCompactionStrategy.java:129 - TWCS skipping check for fully > expired SSTables > DEBUG [CompactionExecutor:356245] 2024-05-23 09:05:00,490 > TimeWindowCompactionStrategy.java:129 - TWCS skipping check for fully > expired SSTables > DEBUG [CompactionExecutor:356244] 2024-05-23 09:06:00,490 > TimeWindowCompactionStrategy.java:129 - TWCS skipping check for fully > expired SSTables > > > > The debug messages above appear in one of my Cassandra nodes every several > minutes, I have a 4 node cluster with RF=3. > > Is there anything I need to do about those messages or its safe to ignore > them > > Thank you for the help > >
