Menene race condition? Bayar da misali da alamarsa.

Question

IT Interview Practice · Accepted Answer

**Race condition bug ne inda sakamako ya dogara da lokacin da ba za a iya hasashe ba na ayyukan concurrent da ke shiga shared state.** Misali na gargajiya shine read-modify-write da ba atomic ba.

## Yadda yake aiki

`counter += 1` yana kama da atomic amma a zahiri matakai uku ne: read, add, write. Threads biyu na iya interleave domin a rasa update.

```text
counter = 0
Thread A: read 0 ─────────── write 1
Thread B:      read 0 ─ write 1
Result: 1  (should be 2 — one increment lost)
```

## Misali

```python
counter = 0
def inc():
    global counter
    for _ in range(100_000):
        counter += 1          # NOT atomic: read, +1, write

# Run two threads, expect 200_000...
# ...but you often get less — a lost update
```

Gyaran shine sa sashe ya zama atomic da lock:

```python
lock = threading.Lock()
def inc():
    global counter
    for _ in range(100_000):
        with lock:            # only one thread in here at a time
            counter += 1
```

## Me ya sa yake da muhimmanci

**Alamar** ita ce abin da ke sa races su zama masu haɗari: sakamako marasa daidaito na wucin gadi, marasa sāke-samuwa waɗanda ke wucewa a tests kuma suna faɗuwa a ƙarƙashin load. Suna ɓoyewa har sai lokaci ya canza — inji mai sauri, ƙarin zirga-zirga, sabon core. Gane shared mutable state a matsayin tushen matsala shine mataki na farko; masu tambaya suna son ganin ka gano read-modify-write da ba a kare ba.

Yadda yake aiki

Misali

Me ya sa yake da muhimmanci

Tambayoyi masu alaƙa