Unexpected EOF on insert to PostgreSQL - postgresql

Question

I have the two tables in postgres database, which is inside docker - data_table where is stored usual types and related data_files_table where is stored file data in bytea type. When I'm inserting in data_table and data_files_table in one transaction from golang service using sqlx, sometimes I get an error:
unexpected EOF
on query of insert to data_files_table. Often, it occurs on data bigger than 7 MB.
In postgres logs I found row, that might be relates:
could not receive data from client: Connection reset by peer
Why this occurs? Is it relate to TOAST, tcp connection killing, or something else?
Here is my code:
func (r *repo) CreateGrantWithDocuments(
ctx context.Context,
model models.Grant,
documents []models.GrantDocument,
) (*pgtype.UUID, error) {
tx, err := r.db.Beginx() // sqlx with pgx driver
if err != nil {
return nil, fmt.Errorf("db.Beginx: %w", err)
}
defer helpdb.Rollback(ctx, r.log, tx)
var grantID pgtype.UUID
err = tx.GetContext(
ctx, &grantID, createGrantSQL, args...) // args doesn't matter, it's ok; query returns id
if err != nil {
return nil, fmt.Errorf("tx.GetContext: %w", err)
}
for _, document := range documents {
data, err := io.ReadAll(document.File)
if err != nil {
return nil, fmt.Errorf("io.ReadAll: %w", err)
}
if err = document.File.Close(); err != nil { // file is an io.ReadCloser from multipart/form-data request
return nil, fmt.Errorf("document.File.Close: %w", err)
}
_, err = tx.NamedExec(createGrantDocumentSQL, document) // ERROR: unexpected EOF
if err != nil {
return nil, fmt.Errorf("tx.NamedExec: %w", err)
}
}
if err = tx.Commit(); err != nil {
return nil, fmt.Errorf("tx.Commit: %w", err)
}
return &grantID, nil
}
I'm using dependencies:
go 1.19
github.com/jmoiron/sqlx v1.3.4 // db connects
github.com/jackc/pgx/v4 v4.14.0 // db driver
I already changed the config on app-side: set idle and open connections count and lifetime to different values, disable idle, increase and decrease lifetime, but nothing helps.
Error doesn't occur locally, only on dev-server.

Answer 1

This problem relates limits of docker container by cgroups. docker stats shows that memory limit is not exceeded, but in fact it is exceeded, because this command doesn't see some types of memory that postgres uses, but cgroups see.
Also, this problem may relates to network problems, but not in my case.
Use rss+cache memory types in monitoring for prevent this problem.