[jira] [Created] (IMPALA-12647) Add Hive compatible way to get modified row count in DMLs (HS2)

["Csaba Ringhofer (Jira)" <ji...@apache.org>]

Csaba Ringhofer created IMPALA-12647:
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             Summary: Add Hive compatible way to get modified row count in DMLs (HS2)
                 Key: IMPALA-12647
                 URL: https://issues.apache.org/jira/browse/IMPALA-12647
             Project: IMPALA
          Issue Type: New Feature
          Components: Clients
            Reporter: Csaba Ringhofer


e,.g after
 insert into t values (1); 
print "modified 1 rows(s)"

Hive and Impala implemented this in  incompatible ways using different HS2 "dialects":
- HIVE-14388 added support using TGetOperationStatusResp.numModifiedRows
- IMPALA-7290 added support using TCloseImpalaOperationResp,TDmlResult

https://github.com/apache/hive/blob/fd92b3926393f0366b87cd55d5a0ad27968f18db/service-rpc/if/TCLIService.thrift#L1120
https://github.com/apache/impala/blob/4114fe8db6ec80b2e1679e946555f91ab7043f2e/common/thrift/ImpalaService.thrift#L966

The Impala patch is newer (probably we didn't know about the Hive solution?), on the other side it is  based on a much older solution in Beeswax. The Impala solution is also more "advanced" and contains extra information relevant  in Kudu upserts/inserts.

Currently impala-shell uses the Impala solution while in Hive compatible strict HS2 mode it doesn't return modified row count.

impyla  doesn't support modified row count: https://github.com/cloudera/impyla/issues/302
There is an extension function that parses Kudu related row counts from the profile:
https://github.com/cloudera/impyla/blob/76f0ba3221e1ff26037e36afbe4a5591168157ce/impala/hiveserver2.py#L205

Ideally there would be  a solution supported by both components and clients wouldn't need to adapt to specific dialects.



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