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From "Zach Amsden (Code Review)" <>
Subject [Impala-ASF-CR] IMPALA-4318: Kudu support for CREATE EXTERNAL TABLE AS SELECT
Date Sat, 04 Mar 2017 01:40:25 GMT
Zach Amsden has posted comments on this change.

Change subject: IMPALA-4318:  Kudu support for CREATE EXTERNAL TABLE AS SELECT

Patch Set 1:

File fe/src/main/cup/sql-parser.cup:

PS1, Line 1033: CreateTableStmt.CreateTableAsSelectStmt
> maybe I'll see why this is necessary later, but this seems odd since it loo
The name is confusing.  It's just a static factory method for creating a CreatTableStmt that
is going to be used as a sub-part of a CreateTableAsSelectStmt (and it needs to know that).
File fe/src/main/java/org/apache/impala/analysis/

PS1, Line 68:   public static CreateTableStmt CreateTableAsSelectStmt(TableDef tableDef) {
            :     CreateTableStmt stmt = new CreateTableStmt(tableDef);
            :     stmt.createAsSelect_ = true;
            :     return stmt;
            :   }
> yeah, per my comment in sql-parser this seems odd to have this parameter on
I didn't want to override the constructor for CreateTableStmt with a boolean parameter 'isCreateAsSelect'
- in 2 years nobody is going to know why some boolean true is passed or what it does and it
isn't clear from the calling context.  So instead I created a static factory method for CreateTableStmt
that tells you exactly what it is doing.

Perhaps a more terse name would be better and it does look confusing that it is named the
same as another statement.

I can't just set isExternal = true because that can also be true without the context of CTAS.
 We need to know whether this table is to be created from a select, or have column data ingested
from an external table.  The fact that it is an external table is now orthogonal to that.

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Gerrit-MessageType: comment
Gerrit-Change-Id: I9aa82809a6c0c5e6386827314b7e5b520c1a6633
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Zach Amsden <>
Gerrit-Reviewer: Dan Hecht <>
Gerrit-Reviewer: Dimitris Tsirogiannis <>
Gerrit-Reviewer: Matthew Jacobs <>
Gerrit-Reviewer: Zach Amsden <>
Gerrit-HasComments: Yes

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