Hi Dinesh,

No. And I am not really planning to. Too early to start looking for other workarounds I think (I could also put the whole stuff into a Linux based Docker container and run from there if it gets to that point - its supported by our everything) before it is confirmed fact that there is no plan from Cassandra Devs to normally support Windows in Cassandra 4.0. Currently it is not the case as far as I see so for now more interested about intentions - that was the goal of my mail. Plus of course also give myself a chance to let it turn out if I am missing a config options somewhere somehow... :-) Code base is pretty big I absolutely have no overview of course. Chance is high I am missing something... :-)


Attila Wind

Mobile: +36 31 7811355

On 2019. 05. 16. 7:49, Dinesh Joshi wrote:
Hi Attila,

Have you tried building & running Cassandra using Windows Subsystem for 
Linux[1]? The integration is seamless and you get a full fledged Linux environment 
on Windows. The overhead is minimal and you should be able to edit in your IDE on 



[1] https://en.wikipedia.org/wiki/Windows_Subsystem_for_Linux

On May 15, 2019, at 10:28 PM, Attila Wind <attilaw@swf.technology> wrote:

Hi Devs,

Base question:
How to run Cassandra 4.0 (trunk) version on a Windows based environment without 
getting always the errors like this?
org.apache.cassandra.io.FSReadError: java.io.IOException: Invalid folder 
descriptor trying to create log replica 

Background / Motivation:
In our project we want to use Map/List data types heavily - also combined with 
IN operator. Due to https://issues.apache.org/jira/browse/CASSANDRA-12654 this 
does not work in 3.x but solved in 4.0. Also extended features around the above 
complex data types in 4.0 excites me up. So I decided to do a test deployment 
on our test servers (Linux based) - features worked like charm there.
As a next step I extended our jBehave testing framework to also be able to fire 
up an embedded Cassandra 4.0 for running tests. Since I am developing on 
Windows I started to get the above mentioned FSReadError exceptions however 
folder path is valid.
Same happens if I try to fire up Cassandra 4.0 instances on Windows systems.

More advanced question:
Based on stack traces I took a look into the source. In 
org.apache.cassandra.db.lifecycle.LogReplica and e.g. in open(File file) method 
(along with others) it is using the 
NativeLibrary.tryOpenDirectory(file.getParentFile().getPath()) call - if it 
fails I get the above FSReadError for sure.
And here we arrive to the main point... On Windows the 
org.apache.cassandra.utils.NativeLibraryWindows class is used in the background. But in 
this class basically almost all method implementation is just "throw new 
UnsatisfiedLinkError();" - bingo! This shows me that I have no really hope... If I 
am on Windows I will fail like hell with above errors always.

1. Are you planning to do something around it?

What I did as an ass-saver I have added a "mock" implementation for 3 problematic 
methods by implementing in Java in NativeLibraryWindows class fake_callOpen(), 
fake_callFsync(), fake_callClose() kinda simulating something. fake_callOpen() stores the 
fake fdId => path mapping in an internal Map object. fake_callClose() flushes that out. 
fake_callFsync() gives a WARN if the fdId is uinknown (so fake_callOpen() was not invoked 
earlier). Issue has gone for me after this, Cassandra 4.0 runs fine with all of our test 
cases - I am happy! :-) So.... and but...

2. My quick and dirty implementation shows that I regularly get lots of warnings from my 
fake_callFsync(int fd): "file descriptor {} is unknown so invalid!" which means 
callOpen(int fd) was NOT invoked in prior calling callFsync() for the given descriptor. 
Is that normal??? Should not callOpen() always be invoked??? Could it be a bug somehow???

3. I am really not planning ever run Cassandra (or any other) in Windows based 
PROD system. But developing on Windows still. Wouldn't it make sense to at 
least provide some workaround here for fellow developers like me? At least to 
be able to run the server in Windows (for testing/development purposes only) ...


Attila Wind

Mobile: +36 31 7811355

To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org
For additional commands, e-mail: dev-h...@cassandra.apache.org

Reply via email to