[infinispan-issues] [JBoss JIRA] (ISPN-5035) DeltaAware support for conditional operations

[Radim Vansa (JIRA)]

    [ https://issues.jboss.org/browse/ISPN-5035?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13026254#comment-13026254 ] 

Radim Vansa commented on ISPN-5035:
-----------------------------------

DistributedExecutorService could be better choice, as long as topology does not change (that's probably OK). However, replication to backups wouldn't spare the bandwidth (unless I implement DeltaAware to produce Deltas and setup IGNORE_RETURN_VALUES to reduce bandwith with RPC response). Even more important concern is that the task wouldn't be executed atomically with the lock locked (so that I don't get write skew and don't have to send whole entry for replace - which in fact does not use deltas), so this would require transactional cache.

> DeltaAware support for conditional operations
> ---------------------------------------------
>
>                 Key: ISPN-5035
>                 URL: https://issues.jboss.org/browse/ISPN-5035
>             Project: Infinispan
>          Issue Type: Feature Request
>          Components: Core
>            Reporter: Radim Vansa
>
> Current delta-aware approach is implemented only in PutKeyValueCommand and ApplyDeltaCommand. This implementation does not allow to execute conditional delta-aware commands - or rather it does not allow to return any kind of value (the condition itself can be implemented inside the delta).
> One use-case when this would be required is equivalent of AtomicLong.getAndIncrement(). Currently we can implement this using
> {code}
> Long previous;
> do {
>     previous = cache.get(key);
> } while (cache.replace(key, previous, previous + 1);
> {code}
> which requires at least two RPCs. With more generic interface, such as JCache's EntryProcessor this could be implemented using single RPC.
> (so, this JIRA is basically a request to native support for EntryProcessor)



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