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Posted to dev@phoenix.apache.org by "James Taylor (JIRA)" <ji...@apache.org> on 2016/08/18 15:47:20 UTC

[jira] [Updated] (PHOENIX-2909) Surface checkAndPut through UPDATE statement

     [ https://issues.apache.org/jira/browse/PHOENIX-2909?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

James Taylor updated PHOENIX-2909:
----------------------------------
    Summary: Surface checkAndPut through UPDATE statement  (was: Surface checkAndPut through UPDATE support)

> Surface checkAndPut through UPDATE statement
> --------------------------------------------
>
>                 Key: PHOENIX-2909
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-2909
>             Project: Phoenix
>          Issue Type: Bug
>            Reporter: James Taylor
>
> We can surface atomic checkAndPut like functionality through support of the SQL UPSERT statement.
> For example, the following could use do a get under row lock to perform the row update atomically
> {code}
> UPDATE  my_table SET counter=coalesce(counter,0) + 1 FROM my_table;
> {code}
> To force prior MVCC transactions to complete (making it serializable as an Increment is), we'd have code like this:
> {code}
>     mvcc = region.getMVCC();
>     mvcc.completeMemstoreInsert(mvcc.beginMemstoreInsert());
> {code}
> By users setting auto commit to true and issuing an UPDATE statement over a non transactional table, they'd get a way for row updates to be atomic. This would work especially well to support counters.
> Note that the coalesce call above handles the case where counter is null. This could be made prettier with support for the DEFAULT clause at CREATE TABLE time (PHOENIX-476).



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