presto-main/src/main/java/io/prestosql/operator/aggregation/state/DigestAndPercentileArrayStateFactory.java/DigestAndPercentileArrayStateFactory/ensureCapacity
class DigestAndPercentileArrayStateFactory:        @Override
        public void ensureCapacity(long size)
        {
            digests.ensureCapacity(size);
            percentilesArray.ensureCapacity(size);
        }