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https://issues.apache.org/jira/browse/CASSANALYTICS-77?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Andrew D updated CASSANALYTICS-77:
----------------------------------
    Description: 
With Cassandra 5 and the cassandra-latest.yaml, UCS is selected as the default 
compaction strategy. When upgrading a cluster, via a datacenter switch for 
example, the compaction for system_auth, system_distributed and system_traces 
gets updated to use UCS even though there's still Cassandra 4 nodes within the 
cluster. This leads to a failure mode where a Cassandra 4 node cannot start up 
due to an unknown compaction strategy:
{code:java}
ERROR [main] 2025-07-02 17:09:39,693 CassandraDaemon.java:898 - Exception 
encountered during startup
org.apache.cassandra.exceptions.ConfigurationException: Unable to find 
compaction strategy class 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy' {code}
Even with storage_compatibility_mode, the default compaction strategy is used. 
To mitigate this, we can update the default compaction strategy however the 
system_schema still indicates that UCS is used:
{code:java}
 keyspace_name      | table_name                                 | compaction
--------------------+--------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
        system_auth |                                cidr_groups | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                           cidr_permissions | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                           identity_to_role | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                        network_permissions | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |             resource_role_permissons_index | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                               role_members | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                           role_permissions | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                                      roles | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'} {code}
There isn't an easy way to update the compaction strategy for these tables 
either.

 

 

 

  was:
Hi,

With Cassandra 5 and the cassandra-latest.yaml, UCS is selected as the default 
compaction strategy. When upgrading a cluster, via a datacenter switch for 
example, the compaction for system_auth, system_distributed and system_traces 
gets updated to use UCS even though there's still Cassandra 4 nodes within the 
cluster. This leads to a failure mode where a Cassandra 4 node cannot start up 
due to an unknown compaction strategy:
{code:java}
ERROR [main] 2025-07-02 17:09:39,693 CassandraDaemon.java:898 - Exception 
encountered during startup
org.apache.cassandra.exceptions.ConfigurationException: Unable to find 
compaction strategy class 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy' {code}
Even with storage_compatibility_mode, the default compaction strategy is used. 
To mitigate this, we can update the default compaction strategy however the 
system_schema still indicates that UCS is used:
{code:java}
 keyspace_name      | table_name                                 | compaction
--------------------+--------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
        system_auth |                                cidr_groups | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                           cidr_permissions | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                           identity_to_role | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                        network_permissions | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |             resource_role_permissons_index | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                               role_members | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                           role_permissions | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'}
        system_auth |                                      roles | {'class': 
'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
'target_sstable_size': '1GiB'} {code}
There isn't an easy way to update the compaction strategy for these tables 
either.

 

 

 


> Cassandra uses default compaction strategy in storage_compatibility_mode 
> which can lead to unsupported compaction strategy during upgrades
> ------------------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: CASSANALYTICS-77
>                 URL: https://issues.apache.org/jira/browse/CASSANALYTICS-77
>             Project: Apache Cassandra Analytics
>          Issue Type: Bug
>            Reporter: Andrew D
>            Priority: Normal
>
> With Cassandra 5 and the cassandra-latest.yaml, UCS is selected as the 
> default compaction strategy. When upgrading a cluster, via a datacenter 
> switch for example, the compaction for system_auth, system_distributed and 
> system_traces gets updated to use UCS even though there's still Cassandra 4 
> nodes within the cluster. This leads to a failure mode where a Cassandra 4 
> node cannot start up due to an unknown compaction strategy:
> {code:java}
> ERROR [main] 2025-07-02 17:09:39,693 CassandraDaemon.java:898 - Exception 
> encountered during startup
> org.apache.cassandra.exceptions.ConfigurationException: Unable to find 
> compaction strategy class 
> 'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy' {code}
> Even with storage_compatibility_mode, the default compaction strategy is 
> used. To mitigate this, we can update the default compaction strategy however 
> the system_schema still indicates that UCS is used:
> {code:java}
>  keyspace_name      | table_name                                 | compaction
> --------------------+--------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>         system_auth |                                cidr_groups | {'class': 
> 'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
> 'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
> 'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
> 'target_sstable_size': '1GiB'}
>         system_auth |                           cidr_permissions | {'class': 
> 'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
> 'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
> 'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
> 'target_sstable_size': '1GiB'}
>         system_auth |                           identity_to_role | {'class': 
> 'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
> 'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
> 'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
> 'target_sstable_size': '1GiB'}
>         system_auth |                        network_permissions | {'class': 
> 'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
> 'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
> 'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
> 'target_sstable_size': '1GiB'}
>         system_auth |             resource_role_permissons_index | {'class': 
> 'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
> 'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
> 'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
> 'target_sstable_size': '1GiB'}
>         system_auth |                               role_members | {'class': 
> 'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
> 'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
> 'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
> 'target_sstable_size': '1GiB'}
>         system_auth |                           role_permissions | {'class': 
> 'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
> 'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
> 'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
> 'target_sstable_size': '1GiB'}
>         system_auth |                                      roles | {'class': 
> 'org.apache.cassandra.db.compaction.UnifiedCompactionStrategy', 
> 'max_sstables_to_compact': '64', 'min_sstable_size': '100MiB', 
> 'scaling_parameters': 'T4', 'sstable_growth': '0.3333333333333333', 
> 'target_sstable_size': '1GiB'} {code}
> There isn't an easy way to update the compaction strategy for these tables 
> either.
>  
>  
>  



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