Function getLogRanges

fdbclient/BackupAgentBase.actor.cpp:169–194

Transaction log data is stored by the FoundationDB core in the "backupLogKeys" (i.e., \xff\x02/blog/) keyspace in a funny order for performance reasons. Returns the ranges of keys that contain the data for the given range of versions. assert CLIENT_KNOBS->LOG_RANGE_BLOCK_SIZE % blocksize = 0. Otherwise calculation of hash will be incorrect

// of versions.
// assert CLIENT_KNOBS->LOG_RANGE_BLOCK_SIZE % blocksize = 0. Otherwise calculation of hash will be incorrect
Standalone<VectorRef<KeyRangeRef>> getLogRanges(Version beginVersion,
                                                Version endVersion,
                                                Key destUidValue,
                                                int blockSize) {
	Standalone<VectorRef<KeyRangeRef>> ret;

	Key baLogRangePrefix = destUidValue.withPrefix(backupLogKeys.begin);

	//TraceEvent("GetLogRanges").detail("DestUidValue", destUidValue).detail("Prefix", baLogRangePrefix);

	for (int64_t vblock = beginVersion / blockSize; vblock < (endVersion + blockSize - 1) / blockSize; ++vblock) {
		int64_t tb = vblock * blockSize / CLIENT_KNOBS->LOG_RANGE_BLOCK_SIZE;
		uint64_t bv = bigEndian64(std::max(beginVersion, vblock * blockSize));
		uint64_t ev = bigEndian64(std::min(endVersion, (vblock + 1) * blockSize));
		uint32_t data = tb & 0xffffffff;
		uint8_t hash = (uint8_t)hashlittle(&data, sizeof(uint32_t), 0);

		Key vblockPrefix = StringRef(&hash, sizeof(uint8_t)).withPrefix(baLogRangePrefix);

		ret.push_back_deep(ret.arena(),
		                   KeyRangeRef(StringRef((uint8_t*)&bv, sizeof(uint64_t)).withPrefix(vblockPrefix),
		                               StringRef((uint8_t*)&ev, sizeof(uint64_t)).withPrefix(vblockPrefix)));
	}

	return ret;
}

Standalone<VectorRef<KeyRangeRef>> getApplyRanges(Version beginVersion, Version endVersion, Key backupUid) {
	Standalone<VectorRef<KeyRangeRef>> ret;