Closed and open dimensions for space partitioning

Space partitioning dimensions can be open or closed. A closed dimension has a fixed number of partitions, and usually uses some hashing to match values to partitions. An open dimension does not have a fixed number of partitions, and usually has each chunk cover a certain range. In most cases the time dimension is open and the space dimension is closed.

If you use the create_hypertable command to create your hypertable, then the space dimension is open, and there is no way to adjust this. To create a hypertable with a closed space dimension, create the hypertable with only the time dimension first. Then use the add_dimension command to explicitly add an open device. If you set the range to 1, each device has its own chunks. This can help you work around some limitations of regular space dimensions, and is especially useful if you want to make some chunks readily available for exclusion.