Find the bugRavenDB HiLo implementation
time to read 3 min | 412 words

The follow code is part of RavenDB HiLo implementation:

        private long NextId()
        {
            long incrementedCurrentLow = Interlocked.Increment(ref currentLo);
            if (incrementedCurrentLow > capacity)
            {
                lock (generatorLock)
                {
                    if (Thread.VolatileRead(ref currentLo) > capacity)
                    {
                        currentHi = GetNextHi();
                        currentLo = 1;
                        incrementedCurrentLow = 1;
                    }
                }
            }
            return (currentHi - 1)*capacity + (incrementedCurrentLow);
        }

It contains a bug, can you see it? I took a long time to figure it out, I am ashamed to say.

BTW, you can safely assume that GetNextHi is correct.

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