protected FilterResult filter(AbstractTraceElement<? extends CatalogType> element) {
if (element instanceof TransactionTrace) {
TransactionTrace xact = (TransactionTrace)element;
try {
int partition = p_estimator.getBasePartition(xact);
if (partition == HStoreConstants.NULL_PARTITION_ID) System.err.println(xact.debug(catalog_db));
assert(partition != HStoreConstants.NULL_PARTITION_ID);
double next = rand.nextDouble();
double prob = probs.get(partition);
boolean skip = (next > prob);