Capacity and limitations

The main limit is that, for a single field, you can't store more than 2**31-1 bytes (2,2 Gbytes) of data. The base is physically split into one file per field, so the limit for the whole base is reached when one of the fields exceeds this size

For instance, a string field S takes 2+len(S) bytes on disk, so if you have 100-byte strings you can store up to about 22.000.000 strings. A unicode string U takes 2+len(U.encode('utf-8'))

For other types the limits are :

The memory load is minimum, since no table is stored in memory