Proper way to release resources with defer in a loop?

user_205270 0
Viewed 41151

I need to make SQL queries to database in the loop:

for rows.Next() {

   fields, err := db.Query(.....)
   if err != nil {
      // ...
   }
   defer fields.Close()

   // do something with `fields`

}

What will be better: leave all as is or move defer after loop:

for rows.Next() {

   fields, err := db.Query(.....)
   if err != nil {
      // ...
   }

   // do something with `fields`
}

defer fields.Close()

Or something else ?

deferred-execution go loops
3 Answers

You can construct a local function to solve this problem

    for i := 0; i < 5; i++ {
        func() {
            f, err := os.Open("/path/to/file")
            if err != nil {
                log.Fatal(err)
            }
            defer f.Close()
        }()
    }
user_122039670
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