x/tools/gopls: uses too much memory (60G)

[bobotu]

What version of Go are you using (go version)?

$ go version
go version go1.14 linux/amd64

Does this issue reproduce with the latest release?

Yes

golang.org/x/tools/gopls v0.3.3
    golang.org/x/tools/gopls@v0.3.3 h1:mTFqRDJQmpSsgDDWvbtGnSva1z9uX2XcDszSWa6DhBQ=

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/tuzi/.cache/go-build"
GOENV="/home/tuzi/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/tuzi/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib64/go/1.14"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib64/go/1.14/pkg/tool/linux_amd64"
GCCGO="gccgo"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/tuzi/projects/tidb/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build266011737=/tmp/go-build -gno-record-gcc-switches"

VS Code settings

    "go.useLanguageServer": true,
    "go.autocompleteUnimportedPackages": true,
    "go.formatTool": "goimports",
    "go.lintTool": "golangci-lint",
    "[go]": {
        "editor.formatOnSave": true,
        "editor.codeActionsOnSave": {
            "source.organizeImports": false,
        },
        // Optional: Disable snippets, as they conflict with completion ranking.
        "editor.snippetSuggestions": "none",
    },
    "[go.mod]": {
        "editor.formatOnSave": true,
        "editor.codeActionsOnSave": {
            "source.organizeImports": true,
        },
    },
    "go.languageServerExperimentalFeatures": {
        "format": false,
        "diagnostics": true,
        "documentLink": true
    },
    "go.languageServerFlags": [
        "-rpc.trace",
        "serve",
        "--debug=localhost:6060"
    ],
    "gopls": {
        // Add parameter placeholders when completing a function.
        "usePlaceholders": false,
        // If true, enable additional analyses with staticcheck.
        // Warning: This will significantly increase memory usage.
        "staticcheck": false,
    },

What did you do?

• editor: VS Code
• go project: pingcap/tidb
  After about half an hour, the gopls eat all of my RAM.

What did you expect to see?

Not use too many memory

What did you see instead?

atop says it has used nearly all RAM on my machine.

heap profile

[gopherbot]

Thank you for filing a gopls issue! Please take a look at the Troubleshooting guide, and make sure that you have provided all of the relevant information here.

[heschi]

Thanks for the report. There should be some files named gopls.PID- in your temporary directory, named after heap sizes. Please upload the pair for the largest heap -- I would like to see a goroutine dump that matches this heap dump.

[bobotu]

@heschik gopls.14043-53GiB-heap.pb.gz and gopls.14043-53GiB-goroutines.txt

[heschi]

Thanks again.

I don't see any signs of a bug here but this is a massive heap. Are you using gopls in a large monorepo, or do you have huge code-generated files?

[bobotu]

I'm working with TiDB codebase.
it's a huge project, some dependency may contains huge protobuf generated code.

[paulsubrata55]

Same here. I had to uninstall the gopls as my system went for a toss. I had to hard reboot my system.
I also have huge protobuf generated code.

[heschi]

@paulsubrata55 I'm sorry you're having trouble, but without a profile or a repro there is absolutely nothing anyone can do to help you. Please follow the instructions above.

[heschi]

@bobotu I believe some changes I landed today have improved memory usage on large projects substantially. Could you try master using the instructions at https://github.com/golang/tools/blob/master/gopls/doc/user.md#unstable-versions?

[xhebox]

@heschik opening TiDB at the root directory will eat up all my 8 GB memory(finally killed by OOM). It is a little better if you just use gopls in a very small directory(< 1 GB memory footprint).

I think gopls needs to be more "lazy" about the imported package(at least provide an option to avoid pulling all dependencies)...

[heschi]

@xhebox I'm sorry you're having trouble, but I cannot reproduce the problem. Please follow the instructions above to collect memory usage information.

[xhebox]

@heschik This is the memory profile: at github.com/pingcap/tidb/kv directory, open memdb_buffer.go file, with gopls@v0.0.0-20200626171337-aa94e735be7f.
Since open something at root will crash my computer, here is one small profile, 300-400M inuse, 600-700M alloc.

mem.txt

I don't see any signs of a bug here but this is a massive heap.

Yes, you are right that maybe there is no bug. But I believe that gopls may have parsed all files under kv directory.

Because memdb_buffer.go only imports tidb/kv/memdb(which costs about 100-150MB alloc), three standard libraries, and pingcap/errors. I expect it is about 200MB alloc, but it turns to be 600-700MB alloc.

I would like to let gopls only parse this opening file, lazily load type info(e.g. gopls only loads the info of Iterator when I am typing Ite), or even remove loaded type info aggressively. Or stop parsing new files when a user specified threshold is exceeded.

[ldeng-ustc]

I would like to let gopls only parse this opening file, lazily load type info(e.g. gopls only loads the info of Iterator when I am typing Ite), or even remove loaded type info aggressively. Or stop parsing new files when a user specified threshold is exceeded.

I couldn't agree more. No one needs info of all packages all the time. Instead, memory resource are more valuable.

[ericwq]

this is my go.mod file, after a few gd jump, it consume 4-5G memory, it hurt my build speed badly :

qiwang@Einstein droplocal % more go.mod
module github.com/ericwq/droplocal

go 1.14

require (
        github.com/davecgh/go-spew v1.1.1 // indirect
        github.com/goftp/file-driver v0.0.0-20180502053751-5d604a0fc0c9
        github.com/goftp/server v0.0.0-20190712054601-1149070ae46b
        github.com/grandcat/zeroconf v1.0.0
        github.com/jlaffaye/ftp v0.0.0-20200602180915-5563613968bf
        github.com/kr/pretty v0.1.0 // indirect
        golang.org/x/net v0.0.0-20200226121028-0de0cce0169b // indirect
        golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e // indirect
        gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
        gopkg.in/yaml.v2 v2.2.4 // indirect
)

[heschi]

The original issue reporter is no longer responding and I believe this issue is resolved or at least improved, so I'm closing the issue.

gopls is currently expected to use ~1GiB on a project of any significant size. Memory usage below that is unfortunately not a bug. We need to load a lot of information about each package to type check the project and to support features like Find References.

As I've said multiple times on this issue, I need the gopls.* files from /tmp to investigate memory problems further. Please file a new issue with one attached if you're having trouble, otherwise there is nothing anyone can do to help you.