Internal History Provider or SQLExpress DB

I wold like to understand if it’s better to use internal History Provider o SQLExpress DB for store data that change very often but i don’t need to store it’s for long time.
What i need it’s a circular buffer.
How i can check the filling status of the Internal History Provider?
Thanks in advance for the informations

What edition of Ignition are you using? Only Edge has a cap on the maximum number of records in the internal historian - it’s not an inherent limitation of SQLite, just a restriction we put onto Edge.

I’m using 8.0.12 edition. To make a circular buffer is it preferable to use the internal DB or the external DB?

It’s entirely up to you. There’s no disadvantage to SQLite, is what I’m trying to imply. It’s a single file on disk, which has advantages for backup, but there’s also some limitations as far as query functions available, and SQLite’s approach to data types is a bit odd. If you don’t plan on writing any manual queries, I highly doubt you’ll notice a difference. The “internal” DB (a bit of a misnomer, it’s not internal to Ignition, really) historian also doesn’t require any additional installation or configuration.