public IndexRangeLocation split(
final RowRangeHistogramStatistics<?> stats,
final double currentCardinality,
final double targetCardinality) {
if (stats == null) {
return null;
}
final double thisCardinalty = rangeLocationPair.getCardinality();
final double fraction = (targetCardinality - currentCardinality) / thisCardinalty;
final int splitCardinality = (int) (thisCardinalty * fraction);
final byte[] start = rangeLocationPair.getRange().getStart().getBytes();
final byte[] end = rangeLocationPair.getRange().getEnd().getBytes();
final double cdfStart = stats.cdf(start);
final double cdfEnd = stats.cdf(end);
final byte[] expectedEnd = stats.quantile(cdfStart + ((cdfEnd - cdfStart) * fraction));
final int maxCardinality = Math.max(start.length, end.length);
final byte[] splitKey = expandBytes(expectedEnd, maxCardinality);
if (Arrays.equals(start, splitKey) || Arrays.equals(end, splitKey)) {
return null;
}
final String location = rangeLocationPair.getLocation();
try {
final RangeLocationPair newPair =
new RangeLocationPair(
new HBaseMRRowRange(
rangeLocationPair.getRange().getStart(), new ByteArrayId(splitKey)),
location,
splitCardinality);
rangeLocationPair =
new RangeLocationPair(
new HBaseMRRowRange(
new ByteArrayId(splitKey), rangeLocationPair.getRange().getEnd()),
location,
rangeLocationPair.getCardinality() - splitCardinality);
return new IndexRangeLocation(newPair, index);
} catch (final java.lang.IllegalArgumentException ex) {
LOGGER.info("Unable to split range: " + ex.getLocalizedMessage());
return null;
}
}
private static RowRangeHistogramStatistics<?> getRangeStats(
final PrimaryIndex index,
final List<DataAdapter<Object>> adapters,
final AdapterStore adapterStore,
final DataStatisticsStore store,
final String[] authorizations) {
RowRangeHistogramStatistics<?> singleStats = null;
for (final DataAdapter<?> adapter : adapters) {
final RowRangeHistogramStatistics<?> rowStat =
(RowRangeHistogramStatistics<?>)
store.getDataStatistics(
adapter.getAdapterId(),
RowRangeHistogramStatistics.composeId(index.getId()),
authorizations);
if (singleStats == null) {
singleStats = rowStat;
} else {
singleStats.merge(rowStat);
}
}
return singleStats;
}
private static double getCardinality(
final RowRangeHistogramStatistics<?> rangeStats, final HBaseMRRowRange range) {
return rangeStats == null
? getRangeLength(range)
: rangeStats.cardinality(range.getStart().getBytes(), range.getEnd().getBytes());
}