Severe performance issues

[ShacharHarshuv]

🐞 bug report

Is this a regression?

No, it has been broken for as long as I was using the extension.

Description

Possible reopen of #2131

For as long as I've been using vscode, various language service features, particularly "Go to references" and "Go to definition" have been very very slow to the point they are unusable. I'm talking 4+ seconds each (sometimes so long it seems like nothing happens)
This happens on the first try for a particular symbol. Subsequent tries for the same symbol are fast. It doesn't consistently happen, and I'm not sure why.

This could happen immediately (or almost immediately) after opening vscode, restarting language server doesn't help.
Disabling the angular language service and relying on the ts language service instead makes it work, but of course it means angular specific syntax (like templates) wouldn't work.

I verified this reproduces on at least 2 different code bases, suggesting it's not a specific problem with my codebase. Though I can't reproduce 100% consistently. I'm not sure why it sometimes happen and sometimes not.

This is still reproducing in the most up to date version 20.2.2.

Other potentially related issues:

• Opening "options" with alt+enter takes forever, and sometimes randomly comes up with "no options available" even though this symbol can actually be imported from somewhere. (The same thing would sometimes work and sometimes not work)

Bug Type

• Angular Language Service VSCode extension
• Angular Language Service server

I'm not sure where exactly the bug is out of these two options

Reproduction

As far as I can tell this could happen with any code base of significant size and any symbol you try to "go to", particularly if you haven't opened the relevant files recently.

Logs

Trace logs immediately after sending such a request. This one took almost 7 seconds. Except the request, the results and the times it doesn't seem like there are many useful information here - let me know what other experiments I can do to give you guys more insights.

[Trace - 4:00:00 PM] Sending request 'textDocument/codeLens - (7)'.
Params: {
    "textDocument": {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/_export-segment-definition.ts"
    }
}


[Trace - 4:00:02 PM] Received response 'textDocument/references - (6)' in 6704ms.
Result: [
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/_export-segment-definition.ts",
        "range": {
            "start": {
                "line": 6,
                "character": 17
            },
            "end": {
                "line": 6,
                "character": 44
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-census-quintiles.ts",
        "range": {
            "start": {
                "line": 16,
                "character": 9
            },
            "end": {
                "line": 16,
                "character": 36
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-census-quintiles.ts",
        "range": {
            "start": {
                "line": 18,
                "character": 48
            },
            "end": {
                "line": 18,
                "character": 75
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-ecpm-segment.ts",
        "range": {
            "start": {
                "line": 13,
                "character": 9
            },
            "end": {
                "line": 13,
                "character": 36
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-ecpm-segment.ts",
        "range": {
            "start": {
                "line": 15,
                "character": 37
            },
            "end": {
                "line": 15,
                "character": 64
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-exploration-criteria-segment.ts",
        "range": {
            "start": {
                "line": 5,
                "character": 9
            },
            "end": {
                "line": 5,
                "character": 36
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-exploration-criteria-segment.ts",
        "range": {
            "start": {
                "line": 7,
                "character": 52
            },
            "end": {
                "line": 7,
                "character": 79
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-exploration-results-segment.ts",
        "range": {
            "start": {
                "line": 16,
                "character": 9
            },
            "end": {
                "line": 16,
                "character": 36
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-exploration-results-segment.ts",
        "range": {
            "start": {
                "line": 27,
                "character": 3
            },
            "end": {
                "line": 27,
                "character": 30
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-geo-indexing-segment.ts",
        "range": {
            "start": {
                "line": 11,
                "character": 9
            },
            "end": {
                "line": 11,
                "character": 36
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-geo-indexing-segment.ts",
        "range": {
            "start": {
                "line": 13,
                "character": 44
            },
            "end": {
                "line": 13,
                "character": 71
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-poi-coverage-segment.ts",
        "range": {
            "start": {
                "line": 14,
                "character": 9
            },
            "end": {
                "line": 14,
                "character": 36
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-poi-coverage-segment.ts",
        "range": {
            "start": {
                "line": 17,
                "character": 44
            },
            "end": {
                "line": 17,
                "character": 71
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-proximity-poi-segment.ts",
        "range": {
            "start": {
                "line": 9,
                "character": 9
            },
            "end": {
                "line": 9,
                "character": 36
            }
        }
    },
    {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/inject-proximity-poi-segment.ts",
        "range": {
            "start": {
                "line": 12,
                "character": 45
            },
            "end": {
                "line": 12,
                "character": 72
            }
        }
    }
]


[Trace - 4:00:02 PM] Received response 'textDocument/codeLens - (7)' in 1560ms.
No result returned.


[Trace - 4:00:02 PM] Received notification 'textDocument/publishDiagnostics'.
Params: {
    "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/plan-route-state/country-query-parameter-name.ts",
    "diagnostics": []
}


[Trace - 4:00:02 PM] Received notification 'textDocument/publishDiagnostics'.
Params: {
    "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/_export-segment-definition.ts",
    "diagnostics": []
}


[Trace - 4:00:02 PM] Received notification 'textDocument/publishDiagnostics'.
Params: {
    "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/plan-route-state/ooh-plan-route-state.service.ts",
    "diagnostics": []
}


[Trace - 4:00:02 PM] Received notification 'textDocument/publishDiagnostics'.
Params: {
    "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/plan-config-state/ooh-plan-config-state.service.ts",
    "diagnostics": []
}


[Trace - 4:00:02 PM] Received notification 'textDocument/publishDiagnostics'.
Params: {
    "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/total-impression-av.ts",
    "diagnostics": []
}


[Trace - 4:00:02 PM] Sending request 'textDocument/foldingRange - (8)'.
Params: {
    "textDocument": {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/_export-segment-definition.ts"
    }
}


[Trace - 4:00:02 PM] Received response 'textDocument/foldingRange - (8)' in 5ms.
Result: []


[Trace - 4:00:04 PM] Sending request 'textDocument/codeLens - (9)'.
Params: {
    "textDocument": {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/_export-segment-definition.ts"
    }
}


[Trace - 4:00:04 PM] Received response 'textDocument/codeLens - (9)' in 3ms.
No result returned.


[Trace - 4:00:04 PM] Sending request 'textDocument/foldingRange - (10)'.
Params: {
    "textDocument": {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/_export-segment-definition.ts"
    }
}


[Trace - 4:00:04 PM] Received response 'textDocument/foldingRange - (10)' in 4ms.
Result: []


[Trace - 4:00:12 PM] Sending request 'textDocument/foldingRange - (11)'.
Params: {
    "textDocument": {
        "uri": "file:///c%3A/Users/Shahar/Documents/repositories/ubiroot/node/web-apps/projects/polaris/src/app/ooh-planning/plan/edit/export/segments/_export-segment-definition.ts"
    }
}


[Trace - 4:00:12 PM] Received response 'textDocument/foldingRange - (11)' in 4ms.
Result: []

I also tried to look into nglangsvc.log immediately after this but I couldn't find what the relevant section (if any) is. So I uploaded the full file here: https://drive.google.com/file/d/1WaWy4rv8cEykcfKqnBEBYGP8ehCxj6Xx/view?usp=sharing (uploading here via github faileD)

🌍 Your Environment

Angular Version:

     _                      _                 ____ _     ___ 
    / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
   / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | | 
  / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | | 
 /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                |___/
    

Angular CLI: 20.1.4
Node: 20.19.4
Package Manager: yarn 1.22.22
OS: win32 x64

Angular: 20.1.4
... animations, cdk, cli, common, compiler, compiler-cli, core
... forms, language-service, material, material-moment-adapter
... platform-browser, platform-browser-dynamic, router        

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.2001.4
@angular-devkit/build-angular   20.1.4
@angular-devkit/core            20.1.4
@angular-devkit/schematics      20.1.4
@schematics/angular             20.1.4
ng-packagr                      20.1.0
rxjs                            7.8.2
typescript                      5.8.3
zone.js                         0.15.0

Extension Version:

20.2.2

VSCode Version:

Version: 1.5.11 (user setup)
VSCode Version: 1.99.3
Commit: 2f2737de9aa376933d975ae30290447c910fdf40
Date: 2025-09-05T03:48:32.332Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Windows_NT x64 10.0.19045

(Note I am using Cursor but this happens in the OG VS Code as well)

Operating System:

Edition	Windows 10 Pro
Version	22H2
Installed on	‎3/‎23/‎2025
OS Build	19045.6216

Note that this also happened in another machine I have with windows 11.

Extension options:

```
"angular.log": "verbose",
"angular.trace.server": "verbose"
```
(I turned these on literally only for the logs I posted here)

Anything else relevant?

I'm not sure what are the conditions for this. I think probably not all users have it happen otherwise it would have been fixed long ago, but it happened to me on both of my machines and in more than one project. I was able to test it in a non-windows machine.

[jpike88]

Using Zed has felt like a huge relief, I recommend giving it a go. The angular plugin has a couple of warts because it's not officially supported by the angular team but there's one thing it is, and that's performant.

[howlettga]

v20.2.2 is extremely slow for some reason. I had to revert to 20.2.1 and it is faster now. This may be a different issue because I am experiencing it for everything.

[atscott]

Received response 'textDocument/references - (6)' in 6704ms.

A request for references requires the entire application to be compiled fully, so it is expected to take some time on the initial request. Are you observing that every request for references thereafter remains slow?

v20.2.2 is extremely slow for some reason. I had to revert to 20.2.1 and it is faster now.

What operations are slow in 20.2.2? The only significant change to language service functionality looks like autocomplete for attributes: angular/angular@c81e345#diff-0dbc44b3fef98374d5d3e635e1173221fda1169d422fd3761ae4cd06b063e126

[doucsag]

I can confirm the language service is so slow I had to turn it off cause it also caused my C# extension to slow down. I have a monorepo with an Angular and dotnet core project and having the language service installed / enabled makes both the C# and Angular language features unusable. Nowadays I only turn it on for troubleshooting.

[atscott]

C# extension to slow down. I have a monorepo with an Angular and dotnet core project

Are you using visual studio or VSCode?

[austinw-fineart]

Are you using visual studio or VSCode?

Both, it slows down severely with both in use.

[JonasDev17]

C# extension to slow down. I have a monorepo with an Angular and dotnet core project

Are you using visual studio or VSCode?

Mostly vscode

[doucsag]

C# extension to slow down. I have a monorepo with an Angular and dotnet core project

Are you using visual studio or VSCode?

vscode

[atscott]

Please note that there is still currently not enough information for this to be actionable.

• can you reproduce the issue in https://github.com/atscott/ng-speed-rebuild or provide a another repository to reproduce the issue in.
• can you provide some of the trace logs when the issue begins to reproduce?
• could run a profile when the issue starts to reproduce and provide it here? A before and after restarting the extension could be useful (and just want to double check: this is restarting the extension only and not all of vscode?)
• additional information about the vscode process could be useful as well, such as https://github.com/microsoft/vscode/wiki/performance-issues#collect-information-about-the-running-vs-code or other profiling such as the render or shared process as mentioned on that page, depending on whether those are problematic. Again, a before and after restarting the extension could be useful.
• what actions, specifically, are slow? As mentioned above, requests for references require full compilation and will be slower on the initial request. Subsequent requests should be faster.
• is there a version that performance regressed? What version? What actions got slower?

[doucsag]

Please note that there is still currently not enough information for this to be actionable.

• can you reproduce the issue in https://github.com/atscott/ng-speed-rebuild or provide a another repository to reproduce the issue in.
• can you provide some of the trace logs when the issue begins to reproduce?
• could run a profile when the issue starts to reproduce and provide it here? A before and after restarting the extension could be useful (and just want to double check: this is restarting the extension only and not all of vscode?)
• additional information about the vscode process could be useful as well, such as https://github.com/microsoft/vscode/wiki/performance-issues#collect-information-about-the-running-vs-code or other profiling such as the render or shared process as mentioned on that page, depending on whether those are problematic. Again, a before and after restarting the extension could be useful.
• what actions, specifically, are slow? As mentioned above, requests for references require full compilation and will be slower on the initial request. Subsequent requests should be faster.
• is there a version that performance regressed? What version? What actions got slower?

I was unable to reproduce it in your repo and also that repo seems a bit broken anyways... (outdated angular.json, mixed dependencies etc.)

Unfortunately I cannot provide the affected repo as its a private one.

@ShacharHarshuv @howlettga @austinw-fineart maybe you guys are able to provide more info on this issue?

I will monitor the issue further and report back if I can produce any evidence.