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Michael Gibney commented on SOLR-13257: --------------------------------------- Thanks [~tomasflobbe] and [~cpoerschke] for your feedback, and for helping move this feature along! I just pushed some commits to address some points raised by [~cpoerschke]: opting for stricter handling of the {{dividend}} param (if present, it must be an integer), and adding/clarifying documentation and javadocs. Most of the changes have to do with added documentation. One functional change was to add support for the ability to explicitly disable implicit hash-based routing (by setting the {{hash}} param config to the empty String, in solr.xml). This idea came up as a consequence of thinking about edge cases while documenting the behavior of replica routing configuration in solr.xml. > Enable replica routing affinity for better cache usage > ------------------------------------------------------ > > Key: SOLR-13257 > URL: https://issues.apache.org/jira/browse/SOLR-13257 > Project: Solr > Issue Type: New Feature > Components: SolrCloud > Reporter: Michael Gibney > Assignee: Tomás Fernández Löbbe > Priority: Minor > Attachments: AffinityShardHandlerFactory.java, SOLR-13257.patch, > SOLR-13257.patch > > Time Spent: 3h 40m > Remaining Estimate: 0h > > For each shard in a distributed request, Solr currently routes each request > randomly via > [ShufflingReplicaListTransformer|https://github.com/apache/lucene-solr/blob/master/solr/core/src/java/org/apache/solr/handler/component/ShufflingReplicaListTransformer.java] > to a particular replica. In setups with replication factor >1, this normally > results in a situation where subsequent requests (which one would hope/expect > to leverage cached results from previous related requests) end up getting > routed to a replica that hasn't seen any related requests. > The problem can be replicated by issuing a relatively expensive query (maybe > containing common terms?). The first request initializes the > {{queryResultCache}} on the consulted replicas. If replication factor >1 and > there are a sufficient number of shards, subsequent requests will likely be > routed to at least one replica that _hasn't_ seen the query before. The > replicas with uninitialized caches become a bottleneck, and from the client's > perspective, many subsequent requests appear not to benefit from caching at > all. -- This message was sent by Atlassian JIRA (v7.6.14#76016) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org