In v5.0, the configuration catalogs and internal state of the TDS has been extensively reworked to be able to scale to large numbers of catalogs, datasets, and internal objects without excessive use of memory. A running TDS can be triggered to reread the configuration catalogs without having to restart, and to reread only changed catalogs, for fast incremental updates. Other features have been added to make writing configuration catalogs more maintainable, including the catalogScan element, and default and standard services. Many of the enhancements are motivated by the use of TDS in the Earth System Grid servers, which can have tens of thousands of catalogs.
The other major enhancement is that the API for Grid datasets is reworked to better support very large data collections, such as those enabled by the new GRIB Collection feature added to TDS in version 4.6. The new API works only with coordinate values (not array indices), which solves various intractable problems that arise when using array index subsetting on large collections.
Future and ongoing efforts in the THREDDS project (netCDF-Java and the TDS) will be discussed including the THREDDS team's support for client-side libraries, specifically Python support.