private void deleteVolumes(final Progress progress,
                               final Set<Long> successfulMetaIdSet,
                               final int successCount) {
        // Delete data volumes.
        info(() -> LogUtil.message("Deleting data volumes for {} meta IDs", successCount));
        final DurationTimer volDeleteTimer = DurationTimer.start();
        final int volCount = dataVolumeDao.delete(successfulMetaIdSet);
        progress.addVolumeDeletionDuration(volDeleteTimer);
        LOGGER.debug(() -> LogUtil.message(
                "{} - Deleted {} data volume records for {} meta IDs in {}",
                TASK_NAME, volCount, successfulMetaIdSet.size(), volDeleteTimer.get()));
    }
Deletes a batch of simpleMetas from the file system and the database.

@param deleteThresholdEpoch The threshold for statusTime, i.e. records <= deleteThresholdEpoch
@param progress             Count of failures that spans multiple batches
@return Those simpleMeta items that could not be deleted for some reason.
stroom-data/stroom-data-store-impl-fs/src/main/java/stroom/data/store/impl/fs/PhysicalDeleteExecutor.java