Hello, Upgraded Cassandra 2.1 to 3.0. We see certain data in few columns being set to "null". These null columns were created during the row creation time.
After looking at the data see a pattern where update was done on these rows. Rows which were updated has data but rows which were not part of the update are set to null. created_on | created_by | id ---------------------------------+---------------------+----------------------------------------- null | null | 12345 sstabledump:- WARN 20:47:38,741 Small cdc volume detected at /var/lib/cassandra/cdc_raw; setting cdc_total_space_in_mb to 1278. You can override this in cassandra.yaml [ { "partition" : { "key" : [ "12345" ], "position" : 5155159 }, "rows" : [ { "type" : "row", "position" : 5168738, "deletion_info" : { "marked_deleted" : "2018-03-28T20:38:08.059999Z", "local_delete_time" : "2018-03-28T20:38:08Z" }, "cells" : [ { "name" : "doc_type", "value" : false, "tstamp" : "2018-03-28T20:38:08.060Z" }, { "name" : "industry", "deletion_info" : { "local_delete_time" : "2018-03-28T20:38:08Z" }, "tstamp" : "2018-03-28T20:38:08.060Z" }, { "name" : "last_modified_by", "value" : "12345", "tstamp" : "2018-03-28T20:38:08.060Z" }, { "name" : "last_modified_date", "value" : "2018-03-28 20:38:08.059Z", "tstamp" : "2018-03-28T20:38:08.060Z" }, { "name" : "locale", "deletion_info" : { "local_delete_time" : "2018-03-28T20:38:08Z" }, "tstamp" : "2018-03-28T20:38:08.060Z" }, { "name" : "postal_code", "deletion_info" : { "local_delete_time" : "2018-03-28T20:38:08Z" }, "tstamp" : "2018-03-28T20:38:08.060Z" }, { "name" : "ticket", "deletion_info" : { "marked_deleted" : "2018-03-28T20:38:08.059999Z", "local_delete_time" : "2018-03-28T20:38:08Z" } }, { "name" : "ticket", "path" : [ "TEMP_DATA" ], "value" : "{\"name\":\"TEMP_DATA\",\"ticket\":\"a42638dae8350e889f2603be1427ac6f5dec5e486d4db164a76bf80820cdf68d635cff5e7d555e6d4eabb9b5b82597b68bec0fcd735fcca\",\"lastRenewedDate\":\"2018-03-28T20:38:08Z\"}", "tstamp" : "2018-03-28T20:38:08.060Z" }, { "name" : "ticket", "path" : [ "TEMP_TEMP2" ], "value" : "{\"name\":\"TEMP_TEMP2\",\"ticket\":\"a4263b7350d1f2683\",\"lastRenewedDate\":\"2018-03-28T20:38:07Z\"}", "tstamp" : "2018-03-28T20:38:08.060Z" }, { "name" : "ppstatus_pf", "deletion_info" : { "marked_deleted" : "2018-03-28T20:38:08.059999Z", "local_delete_time" : "2018-03-28T20:38:08Z" } }, { "name" : "ppstatus_pers", "deletion_info" : { "marked_deleted" : "2018-03-28T20:38:08.059999Z", "local_delete_time" : "2018-03-28T20:38:08Z" } } ] } ] } ]WARN 20:47:41,325 Small cdc volume detected at /var/lib/cassandra/cdc_raw; setting cdc_total_space_in_mb to 1278. You can override this in cassandra.yaml [ { "partition" : { "key" : [ "12345" ], "position" : 18743072 }, "rows" : [ { "type" : "row", "position" : 18751808, "liveness_info" : { "tstamp" : "2017-10-25T10:22:41.612Z" }, "cells" : [ { "name" : "created_by", "value" : "12345" }, { "name" : "created_on", "value" : "2017-10-25 10:22:41.637Z" }, { "name" : "doc_type", "value" : false, "tstamp" : "2017-10-25T10:22:42.487Z" }, { "name" : "last_modified_by", "value" : "12345", "tstamp" : "2017-10-25T10:22:42.487Z" }, { "name" : "last_modified_date", "value" : "2017-11-10 00:09:52.668Z", "tstamp" : "2017-11-10T00:09:52.668Z" }, { "name" : "per_type", "value" : "user" }, { "name" : "lists", "path" : [ "cn.cncn.bpnp" ], "value" : "[\"::accid:ab\",\"::accid:e1\",\"::accid:d2\",\"::accid:d3\",\"::accid:f3\",\"::accid:g3\",\"::accid:f4\",\"::accid:9c486ae5-00b2-3c63-af70-cff2950c4181\"]", "tstamp" : "2017-10-25T10:22:42.782Z" }, { "name" : "ticket", "path" : [ "TEMP_TEMP2" ], "value" : "{\"name\":\"TEMP_TEMP2\",\"ticket\":\"a4263820be49c3a222e0248532bcefc80c773194a804057561a97382e595b51f36bb46b8675589fc89dea4a5c0ceb944d63861b39d63c0067161e84c79328077c650df33530c7625857444711dc4b1051638123694ba6e9e29b1f906663f3\",\"lastRenewedDate\":\"2017-11-10T00:09:52Z\"}", "tstamp" : "2017-11-10T00:09:52.668Z" } ] } ] } ]