[Impala-ASF-CR] Add doc for MT DOP query option.

[John Russell (Code Review)]

John Russell has uploaded a new patch set (#2).

Change subject: Add doc for MT_DOP query option.
..

Add doc for MT_DOP query option.

Change-Id: Ife2786532b425af6d230074f1c0b5c7dcb2b8a92
---
M docs/impala.ditamap
M docs/impala_keydefs.ditamap
M docs/shared/impala_common.xml
A docs/topics/impala_mt_dop.xml
4 files changed, 215 insertions(+), 1 deletion(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/52/5652/2
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Gerrit-MessageType: newpatchset
Gerrit-Change-Id: Ife2786532b425af6d230074f1c0b5c7dcb2b8a92
Gerrit-PatchSet: 2
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: John Russell 
Gerrit-Reviewer: Alex Behm 
Gerrit-Reviewer: Mostafa Mokhtar 
Gerrit-Reviewer: Tim Armstrong 

[Impala-ASF-CR] Add doc for MT DOP query option.

[Alex Behm (Code Review)]

Alex Behm has posted comments on this change.

Change subject: Add doc for MT_DOP query option.
..


Patch Set 1:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/5652/1/docs/topics/impala_mt_dop.xml
File docs/topics/impala_mt_dop.xml:

Line 38:   MT_DOP query option
We should mention somewhere that COMPUTE [INCREMENTAL] STATS on Parquet tables 
is run with MT_DOP=4 by default.

We should also clarify the special meaning of MT_DOP=0, this might need a brief 
introduction to our multi-threading effort, i.e. that we are incrementally 
revamping the execution engine, and MT_DOP=0 will revert to using the "old" 
execution engine.


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Gerrit-MessageType: comment
Gerrit-Change-Id: Ife2786532b425af6d230074f1c0b5c7dcb2b8a92
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: John Russell 
Gerrit-Reviewer: Alex Behm 
Gerrit-Reviewer: Mostafa Mokhtar 
Gerrit-Reviewer: Tim Armstrong 
Gerrit-HasComments: Yes

[Impala-ASF-CR] Add doc for MT DOP query option.

[Tim Armstrong (Code Review)]

Tim Armstrong has posted comments on this change.

Change subject: Add doc for MT_DOP query option.
..


Patch Set 1:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/5652/1/docs/topics/impala_mt_dop.xml
File docs/topics/impala_mt_dop.xml:

Line 43: 
I think it would make sense to document (for now) that many queries don't 
support mt_dop, so that users aren't surprised to get an error after setting 
it. E.g. 

[localhost:21000] > set mt_dop=1;
MT_DOP set to 1
[localhost:21000] > select * from functional.alltypes a1 inner join 
functional.alltypes a2 on a1.id = a2.id limit 4;
Query: select * from functional.alltypes a1 inner join functional.alltypes a2 
on a1.id = a2.id limit 4
Query submitted at: 2017-01-18 14:49:46 (Coordinator: 
http://tarmstrong-box:25000)
ERROR: NotImplementedException: MT_DOP not supported for plans with base table 
joins or table sinks.


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Gerrit-MessageType: comment
Gerrit-Change-Id: Ife2786532b425af6d230074f1c0b5c7dcb2b8a92
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: John Russell 
Gerrit-Reviewer: Alex Behm 
Gerrit-Reviewer: Mostafa Mokhtar 
Gerrit-Reviewer: Tim Armstrong 
Gerrit-HasComments: Yes

[Impala-ASF-CR] Add doc for MT DOP query option.

[Mostafa Mokhtar (Code Review)]

Mostafa Mokhtar has posted comments on this change.

Change subject: Add doc for MT_DOP query option.
..


Patch Set 1:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/5652/1/docs/topics/impala_mt_dop.xml
File docs/topics/impala_mt_dop.xml:

Line 39:   Sets the degree of parallelism used for certain operations that
Should we mention the operations where mt_dop applies?
Compute stats and queries that have scan and aggregate only operators?


Line 42:   and increased memory and CPU usage during statement processing.
I would reword to "ideal balance between response time, memory and CPU". 
As some operations like "compute stats" consume less overall memory due to 
running with less scanner threads.


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Gerrit-MessageType: comment
Gerrit-Change-Id: Ife2786532b425af6d230074f1c0b5c7dcb2b8a92
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: John Russell 
Gerrit-Reviewer: Alex Behm 
Gerrit-Reviewer: Mostafa Mokhtar 
Gerrit-Reviewer: Tim Armstrong 
Gerrit-HasComments: Yes

[Impala-ASF-CR] Add doc for MT DOP query option.

[John Russell (Code Review)]

John Russell has uploaded a new change for review.

  http://gerrit.cloudera.org:8080/5652

Change subject: Add doc for MT_DOP query option.
..

Add doc for MT_DOP query option.

Change-Id: Ife2786532b425af6d230074f1c0b5c7dcb2b8a92
---
M docs/impala.ditamap
M docs/shared/impala_common.xml
A docs/topics/impala_mt_dop.xml
3 files changed, 61 insertions(+), 0 deletions(-)


  git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/52/5652/1
-- 
To view, visit http://gerrit.cloudera.org:8080/5652
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Gerrit-MessageType: newchange
Gerrit-Change-Id: Ife2786532b425af6d230074f1c0b5c7dcb2b8a92
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: John Russell