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From "John Russell (Code Review)" <>
Subject [Impala-ASF-CR] [DOCS] Major update to Impala + Kudu page
Date Thu, 16 Feb 2017 18:16:15 GMT
John Russell has posted comments on this change.

Change subject: [DOCS] Major update to Impala + Kudu page

Patch Set 15:

File docs/topics/impala_explain.xml:

Line 269:       literal values that exactly match the types in the Kudu table, and do not
> Binary predicates and IN list predicates can be pushed to Kudu.
File docs/topics/impala_kudu.xml:

PS14, Line 147: Tablets are
              :               stored by <term>tablet servers</
> 'work' and 'computing' is kind of misleading given kudu is storage. How abo

PS14, Line 150: Where practical, colocate the tablet servers on the same hosts as the DataNodes,
although that is not 
> Though our recommendation will be to colocate Impalads with tservers.

PS14, Line 220: duplicate
> duplicating
Leaving this as-is. You are avoid the condition of having duplicate data, not the action of
duplicating the data.

PS14, Line 220:               On the logical side, the uniqueness constraint allows you to
avoid duplicate data in a table.
> I like this positive spin on our consistency limitations
Done. Hey, there's a ton of stuff that I wrote in the Oracle docs about the positives of being
able to tighten or loosen the constraints on duplicates depending on the circumstances.

PS14, Line 546:                   <codeph>BIT_SHUFFLE</codeph>: rearrange the
bits of the values to efficiently
              :                   compress sequences of values that are identical or vary
only slightly based
              :                   on primary key order.
> according to the compression doc below, this is also compressed with lz4 af

PS14, Line 562: No joy trying keywords UNKNOWN, or GROUP_VARINT with TINYINT and BIGINT.
> can you file a JIRA please

PS14, Line 1100: 
               :           See <xref keyref="kudu_tables"/>
> this doesnt render in the pdf
The relevant link destination is filled in via a different gerrit, not to worry.

PS14, Line 1153: In particular, do not rely on an <codeph>INSERT ... SELECT</codeph>
               :         that selects from the same table into which it is inserting, unless
you include extra
               :         conditions in the <codeph>WHERE</codeph> clause to avoid
reading the newly inserted rows
               :         within the same statement
> this gets repeated very similarly in the next section. not sure which one i
Done. It's intentional so I'll leave it as-is for the moment. One is "here's how to take this
quirk into account during ETL" and the other is "here's the details of the quirk".

PS14, Line 1237: data that is read while a write
               :         operation is in progress
> kudu does have atomic per row operations, so this needs to be clear it refe
File docs/topics/impala_literals.xml:

PS14, Line 401: kudu_bl
This should actually be kudu_blurb to produce the Kudu-specific subheading.

PS14, Line 409: are part of the primary key.
> this is not true, default is nullable except for PK cols

PS14, Line 415: 
              :       </p>
This constraint applies to every column, not to the composite value of all the PK columns.

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Gerrit-MessageType: comment
Gerrit-Change-Id: I76dcb948dab08532fe41326b22ef78d73282db2c
Gerrit-PatchSet: 15
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: John Russell <>
Gerrit-Reviewer: Ambreen Kazi <>
Gerrit-Reviewer: Dimitris Tsirogiannis <>
Gerrit-Reviewer: Jean-Daniel Cryans <>
Gerrit-Reviewer: John Russell <>
Gerrit-Reviewer: Matthew Jacobs <>
Gerrit-Reviewer: Todd Lipcon <>
Gerrit-HasComments: Yes

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