Code RoomRetry holds transaction lock

HardPrep Room Coding #2134

Retry holds transaction lock

Code reviewDatabases & SQLConcurrencySenior–Staff~20 min

Review this Go code that retries a flaky downstream call from inside an open DB transaction.

What a strong answer looks like

Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix, specific and kind.

0:00 of about 20 min

Mark a line and say what kind of problem it is.0 findings

1tx, _ := db.Begin()

2if _, err := tx.Exec("UPDATE accounts SET balance = balance - $1 WHERE id=$2", amt, id); err != nil {

3 tx.Rollback(); return err

4}

5var resp Resp

6for i := 0; i < 5; i++ {

7 resp, err = ledger.Post(ctx, id, amt) // external HTTP, ~1s timeout each

8 if err == nil { break }

9 time.Sleep(time.Second)

10}

11tx.Commit()

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