I agree too. Given the fact that the method checking the uniqueness of a snapshot name was implemented first, it seems to me that the second method which is not checking it just forgot to do that rather than intentionally doing it like that.
Is it right to assume that we need to address this first in order to implement 18102? If we leave it as it is and we implement vtable with "unique snapshot name globally" in mind and we design that vtable like that, until we fix this issue, snapshots would be overwritten on top of each other if their names are same. https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/service/StorageService.java#L4266 https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/service/StorageService.java#L4317 ________________________________________ From: Paulo Motta <pauloricard...@gmail.com> Sent: Monday, March 6, 2023 5:59 To: Cassandra DEV Subject: [DISCUSS] Should separate snapshots with the same name be allowed in different tables? NetApp Security WARNING: This is an external email. Do not click links or open attachments unless you recognize the sender and know the content is safe. Hi, It's possible to create a snapshot on a set of tables with the same name name/tag with: $ nodetool snapshot --kt-list ks.tb,system.local -t mysnapshot $ nodetool listsnapshots [..] mysnapshot system local 1.16 KiB 21.47 KiB 2023-03-02T13:19:13.757Z mysnapshot ks tb 1.02 KiB 6.08 KiB 2023-03-02T13:19:13.757Z It's also possible to create a snapshot with an existing name, as long as it's in a different table: $ nodetool snapshot --kt-list ks.tb2 -t mysnapshot $ nodetool listsnapshots [..] mysnapshot ks tb2 1.16 KiB 21.47 KiB 2023-03-02T13:19:42.140Z mysnapshot ks tb 1.02 KiB 6.08 KiB 2023-03-02T13:19:13.757Z mysnapshot system local 107 bytes 6.98 KiB 2023-03-02T13:19:13.757Z I found this a bit surprising, since I would expect a snapshot with the same name on different tables to represent the same logical snapshot taken at the same point-in-time. This affects the design of the snapshots virtual table schema on CASSANDRA-18102[1] because the timestamp needs to be included in the primary key to allow distinguishing between different snapshots with the same name, which seems a bit counter-intuitive. I think we should disallow creating a snapshot if another snapshot already exists with the same name in any other table, so snapshots with the same name on different tables are guaranteed to belong to the same logical point-in-time snapshot. Does anyone think it's useful to be able to create separate snapshots with the same names across different tables and we should retain this support? Let me know what do you think, Paulo [1] - https://issues.apache.org/jira/browse/CASSANDRA-18102
