presto-main/src/main/java/io/prestosql/operator/WindowOperator.java/SpillablePagesToPagesIndexes/updateMemoryUsage
class SpillablePagesToPagesIndexes:        void updateMemoryUsage(boolean revocablePagesIndex)
        {
            long pagesIndexBytes = inMemoryPagesIndexWithHashStrategies.pagesIndex.getEstimatedSize().toBytes();
            if (revocablePagesIndex) {
                verify(inMemoryPagesIndexWithHashStrategies.pagesIndex.getPositionCount() > 0);
                localUserMemoryContext.setBytes(0);
                localRevocableMemoryContext.setBytes(pagesIndexBytes);
            }
            else {
                localRevocableMemoryContext.setBytes(0L);
                localUserMemoryContext.setBytes(pagesIndexBytes);
            }
        }