presto-elasticsearch/src/main/java/io/prestosql/elasticsearch/ElasticsearchSplitManager.java/ElasticsearchSplitManager/getSplits
class ElasticsearchSplitManager:    @Override
    public ConnectorSplitSource getSplits(ConnectorTransactionHandle transactionHandle, ConnectorSession session, ConnectorTableHandle table, SplitSchedulingStrategy splitSchedulingStrategy)
    {
        ElasticsearchTableHandle tableHandle = (ElasticsearchTableHandle) table;

        List<ElasticsearchSplit> splits = client.getSearchShards(tableHandle.getIndex()).stream()
                .map(shard -> new ElasticsearchSplit(shard.getId(), shard.getAddress()))
                .collect(toImmutableList());

        return new FixedSplitSource(splits);
    }