kroeders commented on issue #10294: URL: https://github.com/apache/druid/issues/10294#issuecomment-700229405
Hi @dylwylie thanks for taking a look - Our original use case was focused on queryable nodes with failed lookups. The production cluster is around a few hundred queryable nodes and occasionally a lookup will fail to load on a few of them. This can happen for a variety of reasons, like database authentication issues for that particular host. Users may have a variety of queries which may or may not use a variety of lookups, so I'm reluctant to remove a queryable node that could serve other queries. If all lookups have to load before a queryable node announces itself, it also introduces a dangerous point of failure where adding a faulty lookup (or an old database backed lookup failing) could bring down the whole cluster. New lookups and regularly updated lookups introduce some complications too, because the node has already announced itself. The reason I prefer the server selection approach is it only impacts queries with lookups and only does so in a positive way. All queries that already succeed will still succeed and some queries that currently fail will succeed. The cost is a few comparisons during the normal server selection process, which is only if the server selector strategy is used. The only change to core Druid itself to make that work is to make the selector aware of the query so it can route around nodes that aren't suitable for that query. Do you think it would be worth the risk / lost capacity to other queries to filter at the data node level? Is there anything that seems particularly overcomplicated that you see in this approach? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
