fix replicateRate of batchRead in auto-recover is negative

[TakaHiR07]

Motivation

Currently the replicateRate of batchRead in auto-recover may exceed Integer.MAX_VALUE and then become negative, which would result in batchRead operation stuck.

Changes

deal with the negative situation

[StevenLuMT]

good jobs, I have a question: should maxBytesToReplicate use long type?

[TakaHiR07]

good jobs, I have a question: should maxBytesToReplicate use long type?

rateLimiter.acquire(int) just support int value. Besides, Integer.max_value means 2GB throughput, it is enough for most situation.

[TakaHiR07]

good jobs, I have a question: should maxBytesToReplicate use long type?

rateLimiter.acquire(int) just support int value. Besides, Integer.max_value means 2GB throughput, it is enough for most situation because replicate throughput should not be too high.

[lhotari]

I think making this calculation with a long value would produce more correct results.
It's not really realistic, but it I guess it's possible that the resulting value could "wrap around" the negative range and become positive.

Something like this:

Suggested change

	int bytesToReplicateCnt = averageEntrySize.get() * entriesToReplicateCnt;
	bytesToReplicateCnt = bytesToReplicateCnt >= 0 ? bytesToReplicateCnt : Integer.MAX_VALUE;
	maxBytesToReplicate = Math.min(maxBytesToReplicate, bytesToReplicateCnt);
	long bytesToReplicateCnt = (long) averageEntrySize.get() * entriesToReplicateCnt;
	maxBytesToReplicate = bytesToReplicateCnt > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) bytesToReplicateCnt;

[TakaHiR07]

This modification is incorrect. maxBytesToReplicate still may be negative if averageEntrySize.get() is negative, and then replicationThrottle.acquire(maxBytesToReplicate) is stuck.

I think we should "wrap around" the negative value and make it become positive. We should keep the bookie availability first.

[lhotari]

can averageEntrySize.get() be negative?

[lhotari]

I think we should "wrap around" the negative value and make it become positive.

The point is that such value could be positive, but it wouldn't match a meaningful value.

[lhotari]

For example 4294967297 would be just 1 with a "wrapped around" value.

[TakaHiR07]

I get your point. you are right. 4294967297 is a corner case for int value.

Make it to long value would be better.