@Override public Map<Bytes, Map<Column, Bytes>> get(Collection<Bytes> rows, Set<Column> columns) { checkIfOpen(); if (rows.size() == 0 || columns.size() == 0) { return Collections.emptyMap(); } env.getSharedResources().getVisCache().validate(columns); ParallelSnapshotScanner pss = new ParallelSnapshotScanner(rows, columns, env, startTs, stats); Map<Bytes, Map<Column, Bytes>> ret = pss.scan(); for (Entry<Bytes, Map<Column, Bytes>> entry : ret.entrySet()) { updateColumnsRead(entry.getKey(), entry.getValue().keySet()); } return ret; }