ROOT data structure and other database

In ROOT webpage, “ROOT provides a data structure that is extremely powerful for fast access of huge amounts of data - orders of magnitude faster than any database.”

Could someone give me some reference (or values) how fast is the root structure compared with other (commercial) database? Although I use ROOT since many years ago, I don’t have clear idea how fast ROOT can be?


Hi Wenfeng,

The actual performance number varies greatly on many factors (compressed or not, complexity of the (user) data model, size of the data per entry, percentage of the data read, etc.) and is currently affected the strongest by which CPU you are using (the more compression and the more complex data model, the more the CPU is used).

One place where ROOT shines compared to databases is its ability to read column wise (i.e. really really only spend the time necessary to get from disk, decompress and prepare for only the part of the (event) data you need).