x/tools/gopls: reduce memory usage

[mattn]

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

$ go version
go version devel +a10b4cff91 Sun Feb 17 04:46:20 2019 +0000 windows/amd64

Does this issue reproduce with the latest release?

Yes

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

go env Output

$ go env
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\mattn\AppData\Local\go-build
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOOS=windows
set GOPATH=C:\Users\mattn\go
set GOPROXY=
set GORACE=
set GOROOT=C:\go
set GOTMPDIR=
set GOTOOLDIR=C:\go\pkg\tool\windows_amd64
set GCCGO=gccgo
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\Users\mattn\AppData\Local\Temp\go-build232338458=/tmp/go-build -gno-record-gcc-switches

What did you do?

Install gopls from latest x/tools/cmd/gopls, open daemon.go with vim-lsp.

And send textDocument/completion request from vim-lsp.

What did you expect to see?

In my personal experience, I thought gopls take about 500-800MB memory usage.

What did you see instead?

gopls take 3.5 GB memory usage.

[pwaller]

I second this.

Whilst using gopls, I notice a steady increase of memory until it OOMs my system (which has 30GiB spare). I've been using gopls on the go compiler itself, and on the x/tools repository. I regularly have to kill gopls to prevent it from using too much RAM.

[bcmills]

CC @stamblerre @ianthehat

[stamblerre]

We are currently working on a number of improvements to gopls, particularly caching, which should solve a lot of these issues. As of right now, gopls calls go/packages.Load on every keystroke, which is likely why it requires so much memory. There should be updates on this soon.

[gopherbot]

Change https://golang.org/cl/164779 mentions this issue: internal/lsp: handle initializationOptions

[gopherbot]

Change https://golang.org/cl/165438 mentions this issue: internal/lsp: add cache for type information

[mattn]

I'm trying latest master branch with same file.

memory usage is improved considerably. And completion seems to be faster.

[stamblerre]

Closing for now, we can reopen as needed.

[speedwheel]

Is this normal? I get 7gb usage from gopls.exe