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Coalescing duplicate in-flight requests: one shared result for concurrent callers

Runs identical concurrent requests through a single shared call, caching the result while it's in flight and returning the same value to all callers.

concurrency threading coalescing

Python

import time
import threading
from collections import defaultdict


class CoalescingExecutor:
    def __init__(self):
        self._locks = defaultdict(threading.Lock)
        self._in_flight = {}

    def execute(self, key, func):
        with self._locks[key]:
            if key in self._in_flight:
                re…

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