[ 
https://issues.apache.org/jira/browse/PHOENIX-6?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15576149#comment-15576149
 ] 

Cameron Hatfield edited comment on PHOENIX-6 at 10/14/16 6:43 PM:
------------------------------------------------------------------

It would work for me, though I'm not sure if it would be consistent the other 
statements that exist within phoenix, as far as read isolation goes. 
Specifically, with the following ordering: 
* UPSERT DUPLICATE KEY
* UPSERT FROM SELECT
* UPSERT DUPLICATE KEY
* UPSERT FROM SELECT
Does the first FROM SELECT see the results of the first DUPLICATE KEY? Does the 
second DUPLICATE KEY see the results from the first FROM SELECT? Does the 
second FROM SELECT see the results from the first FROM SELECT?

Would definitely be counter intuitive if only some statements in the same 
commit batch could occur in different orders. It might be better, at least long 
term, just to support per-statement auto-commit batching at the client level 
(since commit basically handles non-autocommit batching), though the difficulty 
would be higher.


was (Author: cameron.hatfield):
It would work for me, though I'm not sure if it would be consistent the other 
statements that exist within phoenix, as far as read isolation goes. 
Specifically, with the following ordering: 
*UPSERT DUPLICATE KEY
*UPSERT FROM SELECT
*UPSERT DUPLICATE KEY
*UPSERT FROM SELECT
Does the first FROM SELECT see the results of the first DUPLICATE KEY? Does the 
second DUPLICATE KEY see the results from the first FROM SELECT? Does the 
second FROM SELECT see the results from the first FROM SELECT?

Would definitely be counter intuitive if only some statements in the same 
commit batch could occur in different orders. It might be better, at least long 
term, just to support per-statement auto-commit batching at the client level 
(since commit basically handles non-autocommit batching), though the difficulty 
would be higher.

> 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_wip1.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.
> To handle the maintenance of immutable indexes, we'll need to push the 
> maintenance to the server side.
> This is because the mutations for indexes on immutable tables are calculated 
> on the client-side, while this new syntax would potentially modify the value 
> on the server-side.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to