Performance and efficiency of data storage

[smarr]

The current form of storing all measurements in a table does not seem to work very well in practice.

It seems to take a lot of storage, and it seems to be slow to retrieve the data.

We may want to change how measurements are stored.

Initial ideas for possible options:

• use arrays https://www.postgresql.org/docs/12/arrays.html
• use a binary data type: https://www.postgresql.org/docs/12/datatype-binary.html here the idea would be to represent the numbers simply as a sequence of 32bit floats

[smarr]

For the different options, one thing to keep in mind:

https://twitter.com/Envek/status/1526922431780233218?t=l09q22EVlOSKsw41QHAXmA&s=19

Though, we don't need to worry about the cost of updates, since data is immutable.

[smarr]

First work is done in #100.

[smarr]

First set of benchmarks is implemented with #115.