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From "Mithun Radhakrishnan (JIRA)" <>
Subject [jira] [Commented] (HIVE-13509) HCatalog getSplits should ignore the partition with invalid path
Date Wed, 13 Apr 2016 23:03:25 GMT


Mithun Radhakrishnan commented on HIVE-13509:

+[~daijy], [~rohini].

One possible concern is the disconnect between Hive and Pig:
# When one attempts to consume a *non-existent* directory (i.e. not just an empty directory)
through Pig, one gets a failure.
# When one attempts to consume a non-existent partition (e.g. {{dt='3016-04-13'}}) in Hive,
via  an unsatisfied partition-predicate, the query runs successfully (and returns nothing).

In ETL jobs using Pig, we might actually prefer a failure when the input data isn't available.
Wouldn't this fix break those semantics for Pig?

> HCatalog getSplits should ignore the partition with invalid path
> ----------------------------------------------------------------
>                 Key: HIVE-13509
>                 URL:
>             Project: Hive
>          Issue Type: Improvement
>          Components: HCatalog
>            Reporter: Chaoyu Tang
>            Assignee: Chaoyu Tang
>         Attachments: HIVE-13509.patch
> It is quite common that there is the discrepancy between partition directory and its
HMS metadata, simply because the directory could be added/deleted externally using hdfs shell
command. Technically it should be fixed by MSCK and alter table .. add/drop command etc, but
sometimes it might not be practical especially in a multi-tenant env. This discrepancy does
not cause any problem to Hive, Hive returns no rows for a partition with an invalid (e.g.
non-existing) path, but it fails the Pig load with HCatLoader, because the HCatBaseInputFormat
getSplits throws an error when getting a split for a non-existing path. The error message
might looks like:
> {code}
> Caused by: org.apache.hadoop.mapred.InvalidInputException: Input path does not exist:
> 	at org.apache.hadoop.mapred.FileInputFormat.singleThreadedListStatus(
> 	at org.apache.hadoop.mapred.FileInputFormat.listStatus(
> 	at org.apache.hadoop.mapred.FileInputFormat.getSplits(
> 	at org.apache.hive.hcatalog.mapreduce.HCatBaseInputFormat.getSplits(
> 	at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigInputFormat.getSplits(
> {code}

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