[ome-users] concurrent OMERO Java API login for multiple users?

[Mario Emmenlauer]

Dear Josh,

great, that sounds good! I will give it a try and see how it goes!

All the best,

    Mario



On 14.08.2017 08:33, Josh Moore wrote:
> On Sun, Aug 13, 2017 at 3:13 PM, BioDataAnalysis // Mario Emmenlauer
> <memmenlauer at biodataanalysis.de> wrote:
>>
>> Dear OME,
> 
> Hi Mario,
> 
> 
>> Are there statics in the API that forbid multiple concurrent logins?
> 
> There are no known structures that would prevent multiple logins from
> a single JVM. Any would count as a significant bug.
> 
> 
>> How thread-safe is the API?
> 
> The only services that have concurrency constraints are those around
> the StatefulServiceInterface:
> 
> https://github.com/openmicroscopy/openmicroscopy/blob/develop/components/blitz/resources/omero/ServicesF.ice#L36
> 
> The server itself will lock method calls that need protection, but
> since the service maintains state for the client, ultimately
> responsibility of sensible use falls on the caller. (For example, it
> doesn't make sense for one thread to change the current image of a
> service if another thread is still expecting to load planes or
> thumbnails from the previous image)
> 
> 
>> And how resource-hungry is a new login?
>> I'd expect login to be rather slow because I assume it will initialize
>> a number of resources. Am I mistaken?
> 
> Not horribly slow, but yes, there are a number of mostly security
> checks which occur on session creation. I'd expect several dozen
> within a minute or so to be acceptable. Several hundred in the same
> time period will likely start to create issues, especially if
> continued over a long-period of time; and several thousand would
> almost certainly require server adjustments.
> 
> 
>> Thanks and all the best,
>>     Mario Emmenlauer
> 
> All the best,
> ~Josh.




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