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Posted to issues@kudu.apache.org by "Todd Lipcon (JIRA)" <ji...@apache.org> on 2016/12/12 03:12:58 UTC

[jira] [Created] (KUDU-1802) Deserializing scan tokens should avoid round-trip to master

Todd Lipcon created KUDU-1802:
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             Summary: Deserializing scan tokens should avoid round-trip to master
                 Key: KUDU-1802
                 URL: https://issues.apache.org/jira/browse/KUDU-1802
             Project: Kudu
          Issue Type: Improvement
          Components: client, perf
    Affects Versions: 1.2.0
            Reporter: Todd Lipcon


Currently, KuduScanToken::DeserializeIntoScanner calls KuduClient::OpenTable() which makes a GetTableSchema call to the master. This round trip is a bit expensive because it's always a "thundering herd" for an Impala query or Spark job -- every host deserializes a bunch of scan tokens at the same time and ends up having to back off.

We should consider some ways to avoid this.



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