/** Gets the estimated total amount of data to write during compaction */
private static long getTotalWriteSize(
Iterable<SSTableReader> nonExpiredSSTables,
long estimatedTotalKeys,
ColumnFamilyStore cfs,
OperationType compactionType) {
long estimatedKeysBeforeCompaction = 0;
for (SSTableReader sstable : nonExpiredSSTables)
estimatedKeysBeforeCompaction += sstable.estimatedKeys();
estimatedKeysBeforeCompaction = Math.max(1, estimatedKeysBeforeCompaction);
double estimatedCompactionRatio = (double) estimatedTotalKeys / estimatedKeysBeforeCompaction;
return Math.round(
estimatedCompactionRatio
* cfs.getExpectedCompactedFileSize(nonExpiredSSTables, compactionType));
}
