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Cao Manh Dat updated SOLR-9835: ------------------------------- Attachment: SOLR-9835.patch > Create another replication mode for SolrCloud > --------------------------------------------- > > Key: SOLR-9835 > URL: https://issues.apache.org/jira/browse/SOLR-9835 > Project: Solr > Issue Type: Bug > Security Level: Public(Default Security Level. Issues are Public) > Reporter: Cao Manh Dat > Assignee: Shalin Shekhar Mangar > Attachments: SOLR-9835.patch, SOLR-9835.patch, SOLR-9835.patch, > SOLR-9835.patch, SOLR-9835.patch, SOLR-9835.patch, SOLR-9835.patch, > SOLR-9835.patch, SOLR-9835.patch, SOLR-9835.patch, SOLR-9835.patch, > SOLR-9835.patch > > > The current replication mechanism of SolrCloud is called state machine, which > replicas start in same initial state and for each input, the input is > distributed across replicas so all replicas will end up with same next state. > But this type of replication have some drawbacks > - The commit (which costly) have to run on all replicas > - Slow recovery, because if replica miss more than N updates on its down > time, the replica have to download entire index from its leader. > So we create create another replication mode for SolrCloud called state > transfer, which acts like master/slave replication. In basically > - Leader distribute the update to other replicas, but the leader only apply > the update to IW, other replicas just store the update to UpdateLog (act like > replication). > - Replicas frequently polling the latest segments from leader. > Pros: > - Lightweight for indexing, because only leader are running the commit, > updates. > - Very fast recovery, replicas just have to download the missing segments. > On CAP point of view, this ticket will trying to promise to end users a > distributed systems : > - Partition tolerance > - Weak Consistency for normal query : clusters can serve stale data. This > happen when leader finish a commit and slave is fetching for latest segment. > This period can at most {{pollInterval + time to fetch latest segment}}. > - Consistency for RTG : if we *do not use DQBs*, replicas will consistence > with master just like original SolrCloud mode > - Weak Availability : just like original SolrCloud mode. If a leader down, > client must wait until new leader being elected. > To use this new replication mode, a new collection must be created with an > additional parameter {{liveReplicas=1}} > {code} > http://localhost:8983/solr/admin/collections?action=CREATE&name=newCollection&numShards=2&replicationFactor=1&liveReplicas=1 > {code} -- This message was sent by Atlassian JIRA (v6.3.15#6346) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org