Store ID

The store ID names the history a database file holds. A Sequence Position only means something next to it.

Key words in capitals follow RFC 2119.

What it is#

• A UUID, drawn when the database file is created, and kept in the file (see Schema).
• It changes only when the store is emptied with POST /reset, in development mode. After a reset, Sequence Positions start over at 1, so sequence 5 names a different event.
• A backup file has a store ID of its own, drawn when the backup created it (see Backup).
• Two responses that carry the same store ID come from the same history.

Where it appears#

• In the X-Tamarackdb-Store header of every response that depends on the store (see Conventions).
• In an Append Condition, next to its afterSequence (see Append Condition).

Positions#

A position is a pair: the store ID and a Sequence Position.

• A client that keeps a position MUST keep both together.
• If a later read returns a different store ID, the position no longer means anything: the client starts over from the beginning.
• A projector that keeps its position in a projection doesn’t even see the change: a reset deletes that projection with the rest, and the projector starts from zero on its own.