Andrew Sherman has uploaded a new patch set (#2). ( 
http://gerrit.cloudera.org:8080/11459 )

Change subject: IMPALA-589: Add sql function returning the impalad coordinator 
hostname.
......................................................................

IMPALA-589: Add sql function returning the impalad coordinator hostname.

In every execution of an Impala query, one of the impalad daemons acts
as the coordinator node. In some cases, such as when using a proxy, a
user cannot predict which host will act as the coordinator. To aid in
diagnosis, we provide a sql function which returns the name of the host
on which the coordinator is running.

EXTERNAL DESCRIPTION:

Add a builtin function called coordinator(), which returns the name of
the host which is running the impalad that is acting as the coordinator
for the current query.

IMPLEMENTATION:

All functions are passed a FunctionContext object which is the interface
to the rest of the system for a UDF. From the FunctionContext we get
the TQueryCtx (query context) which contains a TNetworkAddress for
the coordinator. The hostname of the coordinator is copied from the
TNetworkAddress.

Can the TNetworkAddress for the coordinator be unitialized? In the
thrift source the coord_address is marked optional, but my reading of
the code says this is always set in a real impalad. To future-proof the
code a null StringVal is returned if coord_address is unset.

TESTING:
- Added a basic unit test for the new function.
- Added a unit test which simulates the case when coord_address is
  unset.
- Hand tested in a development deployment.
- Ran regression tests and got a clean run.

LIMITATIONS:

This change only adds the coordinator() function.
It does not add the debug_url() function that was mentioned in the
comments on the original Jira.

Change-Id: I94d6e2664ba659b48df53c5c06f67b502c533e47
---
M be/src/exprs/expr-test.cc
M be/src/exprs/utility-functions-ir.cc
M be/src/exprs/utility-functions.h
M common/function-registry/impala_functions.py
M docs/topics/impala_misc_functions.xml
5 files changed, 60 insertions(+), 0 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/59/11459/2
--
To view, visit http://gerrit.cloudera.org:8080/11459
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: newpatchset
Gerrit-Change-Id: I94d6e2664ba659b48df53c5c06f67b502c533e47
Gerrit-Change-Number: 11459
Gerrit-PatchSet: 2
Gerrit-Owner: Andrew Sherman <asher...@cloudera.com>
Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com>
Gerrit-Reviewer: Thomas Marshall <thomasmarsh...@cmu.edu>
Gerrit-Reviewer: Zoram Thanga <zo...@cloudera.com>

Reply via email to