Alex Behm has posted comments on this change. ( )

Change subject: IMPALA-6240: [DOCS] Document PARQUET_ARRAY_RESOLUTION query 

Patch Set 2:

Commit Message:
PS2, Line 10: Cherry-picks: not for 2.x
move above Change-Id
File docs/topics/impala_parquet_array_resolution.xml:
PS2, Line 21: <concept id="parquet_annotate_strings_utf8" rev="2.6.0 
Wrong refs?
PS2, Line 47:       order of the indexed-based resolution for nested arrays in 
I don't think "order" is correct here. "depth" would be more appropriate, but 
probably too confusing


... controls the behavior of the index-based field resolution for nested arrays 
in Parquet.
PS2, Line 48:     </p>
Mention the relevant query option for name vs. index based resolution:

PS2, Line 50:     <p> In Parquet, you can represent an array using a 2-level or 
We should clearly state that the modern, standard representation is 3-level. 
The legacy 2-level scheme is supported for compatibility with older Parquet 
PS2, Line 51:       representation. However, there is no metadata within 
Parquet files to
However, there is no reliable metadata ...
PS2, Line 81:       All of the above options resolves arrays encoded with a 
single level.
PS2, Line 85:       A failure to resolve a schema path with a given array 
resolution policy
A failure to resolve a column/field reference in a query with a given array 
resolution ...
PS2, Line 87:       A mismatch might be treated like a missing field, and it is 
not possible
... like a missing column (returns NULL values), and it is not possible ...
PS2, Line 89:       field' cases.
'legitimately missing column'
PS2, Line 93:       The name-based policy generally does not have the problem 
of ambiguous
Mention how the name based resolution is set:
PS2, Line 116: SingleFieldGroupInList {
Maybe you can give this a more documenty-name such as

PS2, Line 165: ThriftPrimitiveInList {
ParquetSchemaExampleA? The "Thrift" stuff in the name might confuse readers

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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I12696b609609ea16c05d8b7e84b2bae0be6d6cb5
Gerrit-Change-Number: 9534
Gerrit-PatchSet: 2
Gerrit-Owner: Alex Rodoni <>
Gerrit-Reviewer: Alex Behm <>
Gerrit-Reviewer: Alex Rodoni <>
Gerrit-Reviewer: Greg Rahn <>
Gerrit-Reviewer: John Russell <>
Gerrit-Comment-Date: Thu, 08 Mar 2018 05:19:07 +0000
Gerrit-HasComments: Yes

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