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James Taylor updated PHOENIX-6: ------------------------------- Attachment: PHOENIX-6_4.x-HBase-0.98.patch Patch that applies to 4.x-HBase-0.98 branch, [~mujtabachohan]. > 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_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. -- This message was sent by Atlassian JIRA (v6.3.4#6332)