[infinispan-issues] [JBoss JIRA] (ISPN-3451) Read-after-write semantics in transactional mode

[RH Bugzilla Integration (JIRA)]

    [ https://issues.jboss.org/browse/ISPN-3451?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12800266#comment-12800266 ] 

RH Bugzilla Integration commented on ISPN-3451:
-----------------------------------------------

Radim Vansa <rvansa at redhat.com> made a comment on [bug 1002602|https://bugzilla.redhat.com/show_bug.cgi?id=1002602]

In dist sync tx (optimistic, read committed) mode I'd expect that in this situation:

A=1, B=1

startTx
write A=2
write B=2
endTx

if on different node I read B=2, it implies that A=2.
However, as entries are committed during the commit phase in non-defined order (according to context map iteration order), it may happen that B is committed to 2, B is read as 2, A is read as 1 and only after that A is committed to 2.

That is pretty unexpected semantics. It even means that the transactions are not atomic with regards to read operations.
                
> Read-after-write semantics in transactional mode
> ------------------------------------------------
>
>                 Key: ISPN-3451
>                 URL: https://issues.jboss.org/browse/ISPN-3451
>             Project: Infinispan
>          Issue Type: Bug
>          Components: Transactions
>    Affects Versions: 6.0.0.Alpha3
>            Reporter: Radim Vansa
>            Assignee: Mircea Markus
>
> In dist sync tx (optimistic, read committed) mode I'd expect that in this situation:
> A=1, B=1
> startTx
> write A=2
> write B=2
> endTx
> if on different node I read B=2, it implies that A=2.
> However, as entries are committed during the commit phase in non-defined order (according to context map iteration order), it may happen that B is committed to 2, B is read as 2, A is read as 1 and only after that A is committed to 2.
> That is pretty unexpected semantics. It even means that the transactions are not atomic with regards to read operations.

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