Concurrent data insert client (golang) results in first 50 rows missing in database (postgres), but the rest of the 390 are okay - postgresql

Question

I am pulling down stock market data and inserting it into a postgresql database. I have 500 stocks for 60 days of historical data. Each day has 390 trading minutes, and each minute is a row in the database table. The summary of the issue is that the first 20-50 minutes of each day are missing for the each stock. Sometimes its less than 50, but it is never more than 50. Every minute after that for each day is fine (EDIT: on further inspection there are missing minutes all over the place). The maximum matches the max number of concurrent goroutines (https://github.com/korovkin/limiter).
The hardware is set up in my home. I have a laptop that pulls the data, and a 8 year old gaming computer that has been repurposed as a postgres database running in ubuntu. They are connected through a netgear nighthawk x6 router and communicate over the LAN.
The laptop is running a go program that pulls data down and performs concurrent inserts. I loop through the 60 days, for each day I loop through each stock, and for each stock I loop through each minute and insert it into the database via a INSERT statement. Inside the minute loop I used a library that limits the max number of goroutines.
I am fixing it by grabbing the data again, and inserting until the first time the postgres server responds that the entry is a duplicate and violates the unique constraints on the table and breaking out of the loop for each stock.
However, I'd like to know what happened, as I want to better understand how these problems can arise under load. Any ideas?
limit := NewConcurrencyLimiter(50)
for _, m := range ms {
limit.Execute(func() {
m.Insert()
})
}
limit.Wait()

Answer 1

The issue is that using a receiver means that everything is passed by reference. I needed to copy the values I wanted inserted within the for loop, and change the method away from a receiver to one with input parameters
for i, _ := range ms {
value := ms[i]
limit.Execute(func() {
Insert(value)
})
}
limit.Wait()