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https://issues.apache.org/jira/browse/CASSANDRA-11721?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jeremy Hanna updated CASSANDRA-11721:
-------------------------------------
Resolution: Won't Do
Status: Resolved (was: Open)
As discussed previously, CASSANDRA-10383 solves the majority of what this
covers.
> Have a per operation truncate ddl "no snapshot" option
> ------------------------------------------------------
>
> Key: CASSANDRA-11721
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11721
> Project: Cassandra
> Issue Type: Improvement
> Components: Legacy/CQL, Local/Snapshots
> Reporter: Jeremy Hanna
> Priority: Low
> Labels: AdventCalendar2021
>
> Right now with truncate, it will always create a snapshot. That is the right
> thing to do most of the time. 'auto_snapshot' exists as an option to disable
> that but it is server wide and requires a restart to change. There are data
> models, however, that require rotating through a handful of tables and
> periodically truncating them. Currently you either have to operate with no
> safety net (some actually do this) or manually clear those snapshots out
> periodically. Both are less than optimal.
> In HDFS, you generally delete something where it goes to the trash. If you
> don't want that safety net, you can do something like 'rm -rf -skiptrash
> /jeremy/stuff' in one command.
> It would be nice to have something in the truncate ddl to skip the snapshot
> on a per operation basis. Perhaps 'TRUNCATE solarsystem.earth NO SNAPSHOT'.
> This might also be useful in those situations where you're just playing with
> data and you don't want something to take a snapshot in a development system.
> If that's the case, this would also be useful for the DROP operation, but
> that convenience is not the main reason for this option.
> +Additional information for newcomers:+
> This test is a bit more complex that normal LHF tickets but is still
> reasonably easy.
> The idea is to support disabling snapshots when performing a Truncate as
> follow:
> {code}TRUNCATE x WITH OPTIONS = { 'snapshot' : false }{code}
> In order to implement that feature several changes are required:
> * A new Class {{TruncateAttributes}} inheriting from {{PropertyDefinitions}}
> must be create in a similar way to {{KeyspaceAttributes}} or
> {{TableAttributes}}
> * This class should be passed to the {{TruncateStatement}} constructor and
> stored as a field
> * The ANTLR parser logic should be change to retrieve the options and passe
> them to the constructor (see {{createKeyspaceStatement}} for an example)
> * The {{TruncateStatement}} will then need to be modified to take into
> account the new option. Locally it will neeed to call
> {{ColumnFamilyStore#truncateBlockingWithoutSnapshot}} if no snapshot should
> be done instead of {{ColumnFamilyStore#truncateBlocking}}. For non local
> call it will need to pass a new parameter to
> {{StorageProxy#truncateBloking}}. That parameter will then need to be passed
> to the other nodes through the {{TruncateRequest}}.
> * As a new field need to be added to {{TruncateRequest}} this field will need
> to be serialized and deserialized and a new {{MessagingService.Version}} will
> need to be created and set as the current version the new version should be
> 50 (and yes it means that the next release will be a major one 5.0)
> * In {{TruncateVerbHandler}} the new field should be used to determine if
> {{ColumnFamilyStore#truncateBlockingWithoutSnapshot}} or
> {{ColumnFamilyStore#truncateBlocking}} should be called.
> * An in-jvm test should be added in
> {{test/distributed/org/apache/cassandra/distributed/test}} to test that
> truncate does not generate snapshots when the new option is specified.
> Do not hesitate to ping the mentor for more information.
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