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https://issues.apache.org/jira/browse/PHOENIX-6?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15645719#comment-15645719
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Gary Horen commented on PHOENIX-6:
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in the near term this will probably be mostly single rows / commit. As time
goes on other use cases might present larger sized batches.
I would not expect a single row to be updated many times in a single commit.
That would be rare for us.
Peak arrival rate (occuring a handful of times / day) would be in the order of
a handful per second, for now. Modal arrival rate during the day will probably
be several / minute.
The current scenario is counting views for feed items. Some feed items will be
very popular, others will be viewed seldom. My wild guess would be that the
ratio of popular to unpopular will be 10:1 with a gentle downward asymptote
between them.
> 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_v5.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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