Why is that nobody ever talks about dropwizard and kotlin to

Question

Why is that nobody ever talks about dropwizard and kotlin together am I missing something

Shawn · Answer

hi person that uses dropwizard and kotlin together here

Shawn · Answer

what do you expect to find DW is a good Java framework that you can use from Kotlin but there s nothing about it that s especially suited for or against Kotlin

Shawn · Answer

I don t know much about the Spring Boot extensions for kotlin but I m unsure what a similar library for dropwizard would look like

Shawn · Answer

and it s not like there s ever going to be a coroutine ified version of DropWizard that would require quite an overhaul to solve problems that are already dealt with in a more Java way

Shawn · Answer

at that point why not just use Ktor Vert x etc

Mani · Answer

at which point exactly In terms of some benchmarks etc

Shawn · Answer

in terms of what the problem you re looking to solve is

Mani · Answer

Lets say we have 6 7 different applications running on dropwizard and due to the heavy scale our api s and latencies are becoming a bottleneck So how ktor etc will solve the problem

Shawn · Answer

Is there some aspect intrinsic to Kotlin that would solve the problem

fred.deschenes · Answer

I ve used Kotlin with Dropwizard a bunch but apart from the code being written in Kotlin there s no real advantage versus using Java

Shawn · Answer

What you originally asked about was discussion on Kotlin being used with DropWizard and I m trying to say that you don t need discussion on the combination to use it support for DropWizard and Kotlin looks almost identical to support for DropWizard and Java

Shawn · Answer

so does performance and ergonomics for the most part

Mani · Answer

coroutines in case of db calls let me explain the exact problem we ve started facing recently We have a bunch of api calls in a service that are slogging we haven t tried with coroutines yet will it help because there are almost 5k 10k db calls in these api calls

Shawn · Answer

I mean DropWizard provides JDBI but it s older and doesn t come with the Jackson Kotlin extension so you can use data classes in the projects I ve worked on we bring in JDBI3 and the mapper

Mani · Answer

same here

Shawn · Answer

but the rest of the code can t make suspend calls

Mani · Answer

and that actually sucks your thoughts

Mani · Answer

So you mean to say that using coroutines will not help much in my scenario since it is using JDBI3 internally

fred.deschenes · Answer

Dropwizard does support JDBI3 but coroutines won t help you as long as JDBC is synchronous

Shawn · Answer

right that s what I m trying to say

Mani · Answer

Thanks for your time guys slightly smiling face

fred.deschenes · Answer

no problem if you have more questions feel free to poke me directly or just post to < C0B8RC352|server> again

fred.deschenes · Answer

and since I m waiting for Docker to finish building you might want to look at Vert x if you absolutely need to have everything async and Kotlin friendly it has its own async mysql postgres drivers but it s a lot different than working with Dropwizard Spring

fred.deschenes · Answer

and the next Spring boot release will supposedly have much better Kotlin coroutines support

tddmonkey · Answer

Another DW Kotlin user here

Mani · Answer

Our entire core is inherited using Dropwizard template There are more than 10 different huge applications based on it I never thought we ll get to this problem at scale But before I start doing something I want to convince that the server framework change will be more beneficial

Mani · Answer

Coming from a python background I couldn t judge java applications well

Mani · Answer

However my major goal was to refactor that 1 2 services I am accountable for As the latencies became a headache Confused whether to attack it from the DB side or the server side by introducing coroutines etc

fred.deschenes · Answer

but is your bottleneck your actual DB or your access to said DB in Dropwizard

Mani · Answer

access to db in dropwizard is what I am suspecting since the DB s biggest table is only 30 40 million rows and with useful indexes etc

Mani · Answer

Again this is an assumption I can t tell the exact problem

tddmonkey · Answer

Don t assume Measure

Mani · Answer

You re right Started doing it I can tell the DB latencies and API latencies With this information how do I decide which one should I tackle

Mani · Answer

Should I do DB partitioning or writing coroutines

Mani · Answer

That s the reason I wanted to know if coroutines in DW context especially when using JDBI is any useful

fred.deschenes · Answer

definitely work on the DB writing coroutines won t give you better performance there might even make it worse by having multiple queries run in parallel where they would have been sequential before etc

Mani · Answer

Sure I will update this thread if its improved +1 So can I safely take this point from this thread that using coroutines in the context of JDBI will not help much as the JDBC is synchronous

Mani · Answer

Please correct me if I am wrong since its 2 30 AM here and my statements might not make sense

fred.deschenes · Answer

well it s 5 PM on a Friday here so I can t guarantee to make more sense but yeah that seems right stuck out tongue

tddmonkey · Answer

I m gonna generalise quite a lot but if you re using a typical RDBMS i e blocking IO unless you ve done something stupid in your app switching to coroutines or some other flavour of then month isn t going to help you with latency

tddmonkey · Answer

What you re looking at is more than likely a resource contention issue but without more information we won t be able to help you

tddmonkey · Answer

An easy way to figure out if its your actual DB or not throw more app server at the problem does your latency go down or not If it does it s not your DB If it doesn t it s not your app

Mani · Answer

which boils down to increase more number of pods and check got it +1

tddmonkey · Answer

It helps if you have a very thorough understanding about how each of the parts in your architecture manage resources Your DB will have a threadpool and queue I assume you have a connection pool in the DW app too and a queue Then you ll have the thread pool for your DW worker threads and a queue for requests waiting to be served There s undoubtedly more that I ve forgotten it s lateish here You need to understand what happens to your requests as it goes through all of these and which if any is the bottleneck

tddmonkey · Answer

Alternatively use a DB tech that scales horizontally and some of these worries can go away smile

Henry · Answer

Bit late to this party but there are async db drivers in development which may be of interest if you decide that blocking db io is causing you problems <https github com rdbc io rdbc>

Mani · Answer

Thanks < Henry> I will check this