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https://issues.apache.org/jira/browse/CASSANDRA-15158?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ian Cleasby updated CASSANDRA-15158:
------------------------------------
    Comment: was deleted

(was: HI [~michaelsembwever] just hoping to get a bit of love for this ticket. 
Patches can be found in the description above initially done by Vince. Any 
feedback would be great.)

> Wait for schema agreement rather then in flight schema requests when 
> bootstrapping
> ----------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-15158
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-15158
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Cluster/Gossip
>            Reporter: Vincent White
>            Assignee: Ian Cleasby
>            Priority: Normal
>
> Currently when a node is bootstrapping we use a set of latches 
> (org.apache.cassandra.service.MigrationTask#inflightTasks) to keep track of 
> in-flight schema pull requests, and we don't proceed with 
> bootstrapping/stream until all the latches are released (or we timeout 
> waiting for each one). One issue with this is that if we have a large schema, 
> or the retrieval of the schema from the other nodes was unexpectedly slow 
> then we have no explicit check in place to ensure we have actually received a 
> schema before we proceed.
> While it's possible to increase "migration_task_wait_in_seconds" to force the 
> node to wait on each latche longer, there are cases where this doesn't help 
> because the callbacks for the schema pull requests have expired off the 
> messaging service's callback map 
> (org.apache.cassandra.net.MessagingService#callbacks) after 
> request_timeout_in_ms (default 10 seconds) before the other nodes were able 
> to respond to the new node.
> This patch checks for schema agreement between the bootstrapping node and the 
> rest of the live nodes before proceeding with bootstrapping. It also adds a 
> check to prevent the new node from flooding existing nodes with simultaneous 
> schema pull requests as can happen in large clusters.
> Removing the latch system should also prevent new nodes in large clusters 
> getting stuck for extended amounts of time as they wait 
> `migration_task_wait_in_seconds` on each of the latches left orphaned by the 
> timed out callbacks.
>  
> ||3.11||
> |[PoC|https://github.com/apache/cassandra/compare/cassandra-3.11...vincewhite:check_for_schema]|
> |[dtest|https://github.com/apache/cassandra-dtest/compare/master...vincewhite:wait_for_schema_agreement]|
>  



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