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