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https://issues.apache.org/jira/browse/PARQUET-1251?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16413677#comment-16413677
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ASF GitHub Bot commented on PARQUET-1251:
-----------------------------------------
zivanfi commented on a change in pull request #88: PARQUET-1251: Clarify
ambiguous min/max stats for FLOAT/DOUBLE
URL: https://github.com/apache/parquet-format/pull/88#discussion_r177049956
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File path: src/main/thrift/parquet.thrift
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@@ -751,10 +751,19 @@ union ColumnOrder {
* INT32 - signed comparison
* INT64 - signed comparison
* INT96 (only used for legacy timestamps) - undefined
- * FLOAT - signed comparison of the represented value
- * DOUBLE - signed comparison of the represented value
+ * FLOAT - signed comparison of the represented value (*)
+ * DOUBLE - signed comparison of the represented value (*)
* BYTE_ARRAY - unsigned byte-wise comparison
* FIXED_LEN_BYTE_ARRAY - unsigned byte-wise comparison
+ *
+ * (*) Because of the sorting order is not specified properly for floating
+ * point values (relations vs. total ordering) the following
+ * compatibility rules should be applied:
+ * - When looking for NaN values, min and max should be ignored.
Review comment:
Please move this to the end of the list as this is the least important item.
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> Clarify ambiguous min/max stats for FLOAT/DOUBLE
> ------------------------------------------------
>
> Key: PARQUET-1251
> URL: https://issues.apache.org/jira/browse/PARQUET-1251
> Project: Parquet
> Issue Type: Bug
> Components: parquet-format
> Affects Versions: format-2.4.0
> Reporter: Gabor Szadovszky
> Assignee: Gabor Szadovszky
> Priority: Major
> Fix For: format-2.5.0
>
>
> Describe the handling of the ambigous min/max statistics for FLOAT/DOUBLE
> types in case of TypeDefinedOrder. (See PARQUET-1222 for details.)
> * When looking for NaN values, min and max should be ignored.
> * If the min is a NaN, it should be ignored.
> * If the max is a NaN, it should be ignored.
> * If the min is +0, the row group may contain -0 values as well.
> * If the max is -0, the row group may contain +0 values as well.
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