Re: ACIDity of Prevayler 2.6

Hi Klaus, Robert

"Applying transactions to the system
before they are written will cause queries to see unwritten
changes."

I think like Robert that tx should be written only after being
successfully applied to the in-memory model.

The change will not be visible if the tx is written in the same
"lock scope" as the disk IO.

pseudo code:

writeLock.lock()

try {

appyTxOnModel(tx)

writeTxOnDisk(tx);

}

catch (..) {

rollback();

}

finally {

writeLock.unlock();

}

?

Arnaud

On 15/11/2012 03:58, Klaus Wuestefeld wrote:

Hi Robert,

But why does prevayler write to the journal before execution?
We do it the other way around. If the command fails, either
gracefully or fatally, nothing is persisted. If it succeeds but
the append fails we halt the system and report falure to the
calling code. If this is bad, please explain why!

I had answered in my last comment here:
https://gist.github.com/1103582

Klaus

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