impala-reviews mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Michael Ho (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-5483: Automatically disable codegen for small queries
Date Wed, 14 Jun 2017 00:20:59 GMT
Michael Ho has posted comments on this change.

Change subject: IMPALA-5483: Automatically disable codegen for small queries
......................................................................


Patch Set 3:

This is a reasonable extension of the single node optimization. I haven't gone through the
change in details. A couple of questions:

1. how big is the window (in terms of number of rows) in which a query won't trigger single-node
execution but still falls under this new hint ?

2. the caveat (as in single node optimization) is how accurate the estimation is.  Can you
think of some pathological case in which we will regress hugely as a result of this new hint
? I can imagine stale hint being a reason.

3. will the ratio of Ec / Ei be drastically different for small vs large expressions or it
doesn't matter as much after recent inlining change ?

-- 
To view, visit http://gerrit.cloudera.org:8080/7153
To unsubscribe, visit http://gerrit.cloudera.org:8080/settings

Gerrit-MessageType: comment
Gerrit-Change-Id: I273bcee58641f5b97de52c0b2caab043c914b32e
Gerrit-PatchSet: 3
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-Reviewer: Michael Ho
Gerrit-Reviewer: Michael Ho <kwho@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-HasComments: No

Mime
View raw message