presto-memory/src/main/java/io/prestosql/plugin/memory/MemoryMetadata.java/MemoryMetadata/getColumnMetadata
class MemoryMetadata:    @Override
    public synchronized ColumnMetadata getColumnMetadata(ConnectorSession session, ConnectorTableHandle tableHandle, ColumnHandle columnHandle)
    {
        MemoryTableHandle handle = (MemoryTableHandle) tableHandle;
        return tables.get(handle.getId())
                .getColumn(columnHandle)
                .getMetadata();
    }