goroutines taking way too long - go

Question

My understanding is that for an unbuffered channel (jobs) you need both a sender and receiver which I have but something about the order of my code is wrong, it is taking a very long time to complete.
What am I missing here?
const numWorkers = 5
type workerJob struct {
FirstID string
SecondID string
}
func worker(ctx *gin.Context, fs *firestore.Client, jobs <-chan *workerJob, done chan<- bool) {
for job := range jobs {
firstID := job.FirstID
secondID := job.SecondID
if err := saveUpdate(ctx, firstID, secondID, fs); err != nil {
// handle error
}
}
done <- true
}
func UpdateSomething(ctx *gin.Context) {
fs, err := firestore.NewClient(ctx, "some_ID")
if err != nil {
// handle error
}
defer fs.Close()
docsnaps, err := fs.CollectionGroup("someCollection").Where("someCondition", "==", true).Documents(ctx).GetAll()
if err != nil {
// handle error
}
uniqueSomethings := make(map[string]struct{})
jobs := make(chan *workerJob)
done := make(chan bool, numWorkers)
for w := 1; w <= numWorkers; w++ {
go worker(ctx, fs, jobs, done)
}
for _, docsnap := range docsnaps {
var someType SomeType
err := docsnap.DataTo(&someType)
if err != nil {
// handle error
}
for _, prop := range someType.prop {
if strings.Contains(prop.Name, "someString") {
someID := prop.Name[strings.LastIndex(prop.Name, ":")+1:]
if _, ok := uniqueSomethings[someID]; !ok {
uniqueSomethings[someID] = struct{}{}
job := &workerJob{
FirstID: dashboard.CustomerID,
SecondID: someID[strings.Index(someID, "_")+1:],
}
jobs <- job
}
}
}
}
close(jobs)
for i := 1; i <= numWorkers; i++ {
select {
case <-done:
}
}
return
}

Answer 1

I don't fully understand why, but I have been able to bring down the time by a factor of 6! I decided to create a slice of jobs and then create a channel with a predefined capacity - the lenght of that slice, then loop over the slice and send the jobs to the channel here's how it looks:
func UpdateSomething(ctx *gin.Context) {
fs, err := firestore.NewClient(ctx, "some_ID")
if err != nil {
// handle error
}
defer fs.Close()
docsnaps, err := fs.CollectionGroup("someCollection").Where("someCondition", "==", true).Documents(ctx).GetAll()
if err != nil {
// handle error
}
uniqueSomethings := make(map[string]struct{})
jobsArr := make([]*workerJob, 0)
for _, docsnap := range docsnaps {
var someType SomeType
err := docsnap.DataTo(&someType)
if err != nil {
// handle error
}
for _, prop := range someType.prop {
if strings.Contains(prop.Name, "someString") {
someID := prop.Name[strings.LastIndex(prop.Name, ":")+1:]
if _, ok := uniqueSomethings[someID]; !ok {
uniqueSomethings[someID] = struct{}{}
job := &workerJob{
FirstID: dashboard.CustomerID,
SecondID: someID[strings.Index(someID, "_")+1:],
}
jobsArr = append(jobsArr, job)
}
}
}
}
done := make(chan bool, numWorkers)
jobs := make(chan *workerJob, len(jobsArr))
for w := 1; w <= numWorkers; w++ {
go worker(ctx, fs, jobs, done)
}
for _, job := range jobsArr {
jobs <- job
}
close(jobs)
for i := 1; i <= numWorkers; i++ {
select {
case <-done:
}
}
return
}