[rdf4j-dev] SNAPSHOT vs SNAPSHOT_READ

[Håvard Ottestad <hmottestad@xxxxxxxxx>]

Hi,

I was wondering about the difference between SNAPSHOT and SNAPSHOT_READ and why SNAPSHOT_READ was chosen as default for the MemoryStore and NativeStore? Jeen, maybe you could help me understand :)

The reason is that I’m wondering if maybe we should upgrade the default to SNAPSHOT, which is the highest level we have that doesn’t fail transactions for isolation violations.

As a note, relational databases typically default to READ_COMMITTED, or NONE, letting it be up to the user to decide if they want to trade performance for consistency. This would of course not be backward compatible for us to do, and I also don’t think it’s a good idea due to the number of question we would then get about inconsistencies from users who don’t want to have to think about isolation.

Håvard