presto-phoenix/src/main/java/io/prestosql/plugin/phoenix/PhoenixSplitManager.java/PhoenixSplitManager/generateSplits
class PhoenixSplitManager:    private List<InputSplit> generateSplits(QueryPlan queryPlan, List<KeyRange> splits)
            throws IOException
    {
        requireNonNull(queryPlan, "queryPlan is null");
        requireNonNull(splits, "splits is null");

        try (org.apache.hadoop.hbase.client.Connection connection = phoenixClient.getHConnection()) {
            RegionLocator regionLocator = connection.getRegionLocator(TableName.valueOf(queryPlan.getTableRef().getTable().getPhysicalName().toString()));
            long regionSize = -1;
            List<InputSplit> inputSplits = new ArrayList<>(splits.size());
            for (List<Scan> scans : queryPlan.getScans()) {
                HRegionLocation location = regionLocator.getRegionLocation(scans.get(0).getStartRow(), false);
                String regionLocation = location.getHostname();

                if (log.isDebugEnabled()) {
                    log.debug(
                            "Scan count[%d] : %s ~ %s",
                            scans.size(),
                            Bytes.toStringBinary(scans.get(0).getStartRow()),
                            Bytes.toStringBinary(scans.get(scans.size() - 1).getStopRow()));
                    log.debug("First scan : %swith scanAttribute : %s [scanCache, cacheBlock, scanBatch] : [%d, %s, %d] and  regionLocation : %s",
                            scans.get(0), scans.get(0).getAttributesMap(), scans.get(0).getCaching(), scans.get(0).getCacheBlocks(), scans.get(0).getBatch(), regionLocation);
                    for (int i = 0, limit = scans.size(); i < limit; i++) {
                        log.debug("EXPECTED_UPPER_REGION_KEY[%d] : %s", i, Bytes.toStringBinary(scans.get(i).getAttribute(EXPECTED_UPPER_REGION_KEY)));
                    }
                }
                inputSplits.add(new PhoenixInputSplit(scans, regionSize, regionLocation));
            }
            return inputSplits;
        }
    }