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https://issues.apache.org/jira/browse/HIVE-7048?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14004098#comment-14004098
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Swarnim Kulkarni commented on HIVE-7048:
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> I don't understand why CompositeHBaseKeyFactory is pushing down predicates
> at all.
Anything important that needs to be done on the key like setting a filter or a
scan range would need access to the predicates from the query and so I think a
pushdown here is necessary. Also like we discussed before, in order to
appropriately consume the pushdown values it is very important to maintain the
order of pushdown same as the values of the struct.
> why it provides a validator that asserts that only the first field can be
> pushed down.
Agree that this is not required. My only reason behind it was to add in a
preliminary support for pushdown of structs and then later update to a full
fledged support of pushing down multiple fields. Once that support is baked in,
this validator can be removed. Until this is done, the validator will make sure
that wrong predicates do not get pushdown.
> If it's doing this while not setting up corresponding filter, then the result
> will not be correct.
Good point. Since the results won't be correct without proper handling of these
and we do not know how to handle this properly on our end to provide a good
default, I propose that we debar the CompositeKeyHBaseFactory off its "concrete
class" status and add in a abstract method something like
{code}
public abstract HBaseScanRange setupFilter(IndexSearchCondition condition)
throws Exception;
{code}
Consumers can then use the pushed down IndexSearchCondition accordingly to set
a scan and/or filter on the scan range.
Thoughts?
> CompositeKeyHBaseFactory should not use FamilyFilter
> ----------------------------------------------------
>
> Key: HIVE-7048
> URL: https://issues.apache.org/jira/browse/HIVE-7048
> Project: Hive
> Issue Type: Improvement
> Components: HBase Handler
> Reporter: Swarnim Kulkarni
> Assignee: Swarnim Kulkarni
> Priority: Blocker
> Attachments: HIVE-7048.1.patch.txt
>
>
> HIVE-6411 introduced a more generic way to provide composite key
> implementations via custom factory implementations. However it seems like the
> CompositeHBaseKeyFactory implementation uses a FamilyFilter for row key scans
> which doesn't seem appropriate. This should be investigated further and if
> possible replaced with a RowRangeScanFilter.
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