I have created a table with a collection. Inserted a record and took sstabledump of it and seeing there is range tombstone for it in the sstable. Does this tombstone ever get removed? Also when I run sstablemetadata on the only sstable, it shows "Estimated droppable tombstones" as 0.5", Similarly it shows one record with epoch time as insert time for - "Estimated tombstone drop times: 1548384720: 1". Does it mean that when I do sstablemetadata on a table having collections, the estimated droppable tombstone ratio and drop times values are not true and dependable values due to collection/list range tombstones? CREATE TABLE ks.nmtest ( reservation_id text, order_id text, c1 int, order_details map<text, text>, PRIMARY KEY (reservation_id, order_id) ) WITH CLUSTERING ORDER BY (order_id ASC)
user@cqlsh:ks> insert into nmtest (reservation_id , order_id , c1, order_details ) values('3','3',3,{'key':'value'}); user@cqlsh:ks> select * from nmtest ; reservation_id | order_id | c1 | order_details ----------------+----------+----+------------------ 3 | 3 | 3 | {'key': 'value'} (1 rows) [root@localhost nmtest-e1302500201d11e983bb693c02c04c62]# sstabledump mc-5-big-Data.db WARN 02:52:19,596 memtable_cleanup_threshold has been deprecated and should be removed from cassandra.yaml [ { "partition" : { "key" : [ "3" ], "position" : 0 }, "rows" : [ { "type" : "row", "position" : 41, "clustering" : [ "3" ], "liveness_info" : { "tstamp" : "2019-01-25T02:51:13.574409Z" }, "cells" : [ { "name" : "c1", "value" : 3 }, { "name" : "order_details", "deletion_info" : { "marked_deleted" : "2019-01-25T02:51:13.574408Z", "local_delete_time" : "2019-01-25T02:51:13Z" } }, { "name" : "order_details", "path" : [ "key" ], "value" : "value" } ] } ] } SSTable: /data/data/ks/nmtest-e1302500201d11e983bb693c02c04c62/mc-5-big Partitioner: org.apache.cassandra.dht.Murmur3Partitioner Bloom Filter FP chance: 0.010000 Minimum timestamp: 1548384673574408 Maximum timestamp: 1548384673574409 SSTable min local deletion time: 1548384673 SSTable max local deletion time: 2147483647 Compressor: org.apache.cassandra.io.compress.LZ4Compressor Compression ratio: 1.0714285714285714 TTL min: 0 TTL max: 0 First token: -155496620801056360 (key=3) Last token: -155496620801056360 (key=3) minClustringValues: [3] maxClustringValues: [3] Estimated droppable tombstones: 0.5 SSTable Level: 0 Repaired at: 0 Replay positions covered: {CommitLogPosition(segmentId=1548382769966, position=6243201)=CommitLogPosition(segmentId=1548382769966, position=6433666)} totalColumnsSet: 2 totalRows: 1 Estimated tombstone drop times: 1548384720: 1 Does tombstone_threshold of compaction depend on the sstablemetadata threshold value? If so then for tables having collections, this is not a true threshold right?