OmniSharp in VSCode very slow

Question

I'm not sure what happened but all of a sudden OmniSharp has become very slow in VSCode.

Sometimes the autocomplete works immediately sometimes it takes minutes, same for jumping to definitions and the like.

If I disable OmniSharp autocomplete speeds up again for local variables, on occasion OmniSharp gives me a list of functions which will complete what I'm typing but doesn't autoselect the one I've half written.

Is there a way to debug this and identify the cause?

Answer 1

If your question is about identifying the reason, try to check the "Omnisharp Logs" in the Outuput window:

It's normal to see some warnings and even errors in there, but there shouldn't be too many.

You can also try to increase the log level to see more info.

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If you want some temporary relieves, you can also try the following settings:

    "omnisharp.analyzeOpenDocumentsOnly": true,
    // Flip this on/off and feel the difference
    "omnisharp.enableAsyncCompletion": false,
    // Flip this on/off and feel the difference
    "omnisharp.enableMsBuildLoadProjectsOnDemand": false,
    // Maybe more cost up front helps later
    "omnisharp.projectLoadTimeout": 300,
    // Only if using .NET6+, 
    // If not, read about the setting, or make sure you set it to false
    "omnisharp.useModernNet": true,
    // This slows down start normally, 
    // but see if it makes a difference after that
    "omnisharp.path": "latest",
    // Only set this to false to experiment
    // If it improves things, then some analyzer NuGet is the cause
    "omnisharp.enableRoslynAnalyzers": false,
    // Also check "omnisharp." and "csharp." settings for any
    // setting that has the word "suppress" and remove them
    // so you can see all errors and warnings from omnisharp

Answer 2

I think i have found the root of all problems. after disabling and enabling extensions, that i did not use, and notice that none of them were the problem... the problem it self is omnisharp when you enable auto imports... so

Disable auto import in c# extension

• bottom left gear icon -> Settings -> Extensions-> right click c# extension -> extension settings

• in the settings search bar you will get something like this

@ext:ms-dotnettools.csharp

next add @ext:ms-dotnettools.csharp import to the search bar

disable "Omnisharp: Enable Import Completion" option check box.