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https://issues.apache.org/jira/browse/CASSANDRA-19948?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17884581#comment-17884581
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Bowen Song commented on CASSANDRA-19948:
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[~smiklosovic] if that was indeed the cause, how confidence are we that
[these|https://github.com/apache/cassandra/blob/720a1b2704f97d20300cc743b4223557e2c0c12c/src/java/org/apache/cassandra/schema/SchemaKeyspace.java#L562C1-L580C55]
on trunk won't cause schema divergence between the nodes? I believe that they
affect more than just 4.x, and are need for the 4.x to 5.x upgrade.
{code:java}
// As above, only add the memtable column if the table uses a
non-default memtable configuration to avoid RTE
// in mixed operation with pre-4.1 versioned node during upgrades.
if (params.memtable != MemtableParams.DEFAULT)
builder.add("memtable", params.memtable.configurationKey());
// As above, only add the allow_auto_snapshot column if the value is
not default (true) and
// auto-snapshotting is enabled, to avoid RTE in pre-4.2 versioned node
during upgrades
if (!params.allowAutoSnapshot)
builder.add("allow_auto_snapshot", false);
// As above, only add the incremental_backups column if the value is
not default (true) and
// incremental_backups is enabled, to avoid RTE in pre-4.2 versioned
node during upgrades
if (!params.incrementalBackups)
builder.add("incremental_backups", false);{code}
> Changing cdc table property can cause schema disagreement
> ---------------------------------------------------------
>
> Key: CASSANDRA-19948
> URL: https://issues.apache.org/jira/browse/CASSANDRA-19948
> Project: Cassandra
> Issue Type: Bug
> Components: Cluster/Schema
> Reporter: Bowen Song
> Priority: Normal
> Fix For: 4.1.x, 5.0.x, 5.x
>
> Attachments: 4.1.1.txt, 4.1.6.txt, 5.0.0-corrected.txt,
> cdc_schema_disagreement.sh
>
>
> In the cassandra.yaml file, there is a parameter named "cdc_enabled" which
> allows CDC to be enabled or disabled on each individual nodes.
> It has been found that it can cause schema disagreement or discrepancy when
> an "ALTER TABLE ... WITH cdc=..." statement is ran against a node which has
> "cdc_enabled" set to "false" in a cluster in which nodes have mixed
> "true"/"false" values for the "cdc_enabled" settings.
> The exact behaviour of the above is version-dependant.
> On Cassandra 4.1.1, the cluster will end up in the schema disagreement state.
> A rolling restart will bring the schema back in sync, but the changes made to
> the `cdc` table property will be lost.
> On Cassandra 4.1.6, the cluster will not have visible schema disagreement in
> the "nodetool describecluster" command's output, but the "ALTER TABLE"
> statement only has cosmetic effect on the node it is run. The node with
> "cdc_enabled" set to "false" will show the "cdc" table property has changed,
> but this does not affect its behaviour in any way. At the same time, other
> nodes do not see that table property change at all. This is perhaps even
> worse than on 4.1.1, because the alter table statement is silently failing.
> On Casandra 5.0.0, the behaviour is the same as 4.1.6.
> A shell script for reproducing the above described behaviours in Docker, and
> the outputs of it on both 4.1.1 and 4.1.6 and 5.0.0 are attached.
>
> Edit on 25 Sep: added test result on 5.0.0
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