[jira] [Comment Edited] (ACCUMULO-1000) support compare and set

["William Slacum (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ACCUMULO-1000?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13676013#comment-13676013 ] 

William Slacum edited comment on ACCUMULO-1000 at 6/5/13 3:19 PM:
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It seems the implementation Keith gave is for compare and swap, not compare and set. This means that my pre-commit check is an equality operation, which may not be enough. One example that's always used is a bank account- when another person makes a charge to a bank account, they don't necessarily care that the account balance is the same as some initial check (ie, you said you have $100 but the bank says you have $90), I only care that the amount covered by the charged exists in the bank account (ie, this gumbo cost $50 and you have $90, you may pass go).

I think we could hammer in this functionality by using an iterator that checks the precondition and returns a boolean- have you thought about how to add in that to {{ConditionalMutation}}? 
                
      was (Author: bills):
    It seems the implementation Keith gave is for compare and swap, not compare and set. This means that my pre-commit check is an equality operation, which may not be enough. Once example that's always used is a bank account- when another person makes a charge to a bank account, they don't necessarily care that the account balance is the same as some initial check (ie, you said you have $100 but the bank says you have $90), I only care that the amount covered by the charged is exists in the bank account (ie, this gumbo cost $50 and you have $90, you may pass go).

I think we could hammer in this functionality by using an iterator that checks the precondition and returns a boolean- have you thought about how to add in that to {{ConditionalMutation}}? 
                  
> support compare and set
> -----------------------
>
>                 Key: ACCUMULO-1000
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-1000
>             Project: Accumulo
>          Issue Type: New Feature
>          Components: client, tserver
>            Reporter: Keith Turner
>            Assignee: Keith Turner
>             Fix For: 1.6.0
>
>         Attachments: ACCUMULO-1000-proposal-01.html, ACCUMULO-1000-proposal-01.txt
>
>
> Add support to mutation for compare and set operations.  This would allow user to specify that a row must contain certain data for a mutation to be applied.

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