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Posted to dev@ignite.apache.org by "Vladimir Ozerov (JIRA)" <ji...@apache.org> on 2017/11/16 14:48:00 UTC

[jira] [Created] (IGNITE-6937) SQL TX: Support SELECT FOR UPDATE

Vladimir Ozerov created IGNITE-6937:
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             Summary: SQL TX: Support SELECT FOR UPDATE
                 Key: IGNITE-6937
                 URL: https://issues.apache.org/jira/browse/IGNITE-6937
             Project: Ignite
          Issue Type: Task
      Security Level: Public (Viewable by anyone)
            Reporter: Vladimir Ozerov
             Fix For: 2.4


Normally in SQL world readers do not block writers. This is how our SELECT operations should work by default. But we need to add a support for {{SELECT ... FOR UPDATE}} read mode, when reader obtains exclusive lock on read. 

In this mode we lock entries as usual, but then send data back to the caller. First page can be returned directly in our {{LockResponse}}. Next pages should be requested in separate requests. With this approach {{SELECT ,,, FOR UPDATE}} will require only single round-trip to both lock and read data in case of small updates.



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