Re: Implementation PrevaylerEight

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>
> Very nice results. I don't know what PrevaylerEight provides in terms
> of ACID guarantees. How do you compare PrevaylerEight to Prevayler in
> that regard?
>

After reading
http://www.codeproject.com/Tips/683614/Things-to-Know-about-Memory-Mapped-File-in-Java
and other sources, I found the described 1:1 behaviour when using
force/flush after each transaction. So, there's a trade-off between speed
and the big D in ACID. ;-)

So, it depends how critically is to your application, losing some
transactions when the OS crashes. As far as I understand the case, a JVM
crash is not critical, as the memory mapping is managed by the OS, which
cares about writing pending changes to the disk, even if the JVM is down.


> The Prevayler results are still growing almost linearly with 8
> threads. You have to increase the number of threads until the result
> peaks out, possibly with hundreds or even thousands of threads.


The peak is between 800 and 1000 threads (but my CPU utilisation never
exceeds 30%) at approx. 18k ops. There is some
queuing/tx-collecting/batching happening here, right?

Cheers,
Christian

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<div dir=3D"ltr"><div class=3D"gmail_extra"><div class=3D"gmail_quote"><blo=
ckquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left=
-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;paddi=
ng-left:1ex">Very nice results. I don&#39;t know what PrevaylerEight provid=
es in terms<br>
of ACID guarantees. How do you compare PrevaylerEight to Prevayler in<br>
that regard?<br></blockquote><div><br></div><div>After reading=C2=A0<a href=
=3D"http://www.codeproject.com/Tips/683614/Things-to-Know-about-Memory-Mapp=
ed-File-in-Java">http://www.codeproject.com/Tips/683614/Things-to-Know-abou=
t-Memory-Mapped-File-in-Java</a> and other sources, I found the described 1=
:1 behaviour when using force/flush after each transaction. So, there&#39;s=
 a trade-off between speed and the big D in ACID. ;-)</div><div><br></div><=
div>So, it depends how critically is to your application, losing some trans=
actions when the OS crashes. As far as I understand the case, a JVM crash i=
s not critical, as the memory mapping is managed by the OS, which cares abo=
ut writing pending changes to the disk, even if the JVM is down.</div><div>=
=C2=A0</div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0=
.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-s=
tyle:solid;padding-left:1ex">
The Prevayler results are still growing almost linearly with 8<br>
threads. You have to increase the number of threads until the result<br>
peaks out, possibly with hundreds or even thousands of threads.</blockquote=
><div><br></div><div>The peak is between 800 and 1000 threads (but my CPU u=
tilisation never exceeds 30%) at approx. 18k ops. There is some queuing/tx-=
collecting/batching happening here, right?</div><div><br></div><div>Cheers,=
</div><div>Christian</div></div></div></div>

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