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https://issues.apache.org/jira/browse/PHOENIX-6?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15612995#comment-15612995
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Samarth Jain commented on PHOENIX-6:
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Thanks for the explanation, makes sense.
bq. This is already covered as the test is parameterized with indexes added for
both the indexed and covered column case.
Ah, missed that. How about a covered column test case for local indexes too?
Last two questions, :)
Do you think queries with a subquery in the update clause will compile? Also
what if the UDF has a row key column. Will the expression compiler be able to
figure that out?
> Support ON DUPLICATE KEY construct
> ----------------------------------
>
> Key: PHOENIX-6
> URL: https://issues.apache.org/jira/browse/PHOENIX-6
> Project: Phoenix
> Issue Type: New Feature
> Reporter: James Taylor
> Assignee: James Taylor
> Fix For: 4.9.0
>
> Attachments: PHOENIX-6.patch, PHOENIX-6_4.x-HBase-0.98.patch,
> PHOENIX-6_v2.patch, PHOENIX-6_v3.patch, PHOENIX-6_v4.patch,
> PHOENIX-6_wip1.patch, PHOENIX-6_wip2.patch, PHOENIX-6_wip3.patch,
> PHOENIX-6_wip4.patch
>
>
> To support inserting a new row only if it doesn't already exist, we should
> support the "on duplicate key" construct for UPSERT. With this construct, the
> UPSERT VALUES statement would run atomically and would thus require a read
> before write which would obviously have a negative impact on performance. For
> an example of similar syntax , see MySQL documentation at
> http://dev.mysql.com/doc/refman/5.7/en/insert-on-duplicate.html
> See this discussion for more detail:
> https://groups.google.com/d/msg/phoenix-hbase-user/Bof-TLrbTGg/68bnc8ZcWe0J.
> A related discussion is on PHOENIX-2909.
> Initially we'd support the following:
> # This would prevent the setting of VAL to 0 if the row already exists:
> {code}
> UPSERT INTO T (PK, VAL) VALUES ('a',0)
> ON DUPLICATE KEY IGNORE;
> {code}
> # This would increment the valueS of COUNTER1 and COUNTER2 if the row already
> exists and otherwise initialize them to 0:
> {code}
> UPSERT INTO T (PK, COUNTER1, COUNTER2) VALUES ('a',0,0)
> ON DUPLICATE KEY UPDATE COUNTER1 = COUNTER1 + 1, COUNTER2 = COUNTER2 + 1;
> {code}
> So the general form is:
> {code}
> UPSERT ... VALUES ... [ ON DUPLICATE KEY [IGNORE | UPDATE
> <column>=<expression>, ...] ]
> {code}
> The following restrictions will apply:
> * The <column> may not be part of the primary key constraint - only KeyValue
> columns will be allowed.
> * This new clause cannot be used with
> ** Immutable tables since the whole point is to atomically update a row in
> place which isn't allowed for immutable tables.
> ** Transactional tables because these use optimistic concurrency as their
> mechanism for consistency and isolation.
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