Comparison
Open table formatvsSnapshot isolation
Open table format
there is a metadata layer over the files that says exactly which files are in the table right now, so two writers no longer overwrite each other.
A specification that turns a directory of files into a table with atomic commits, snapshot isolation and schema evolution, by keeping an explicit manifest of the files each version contains. It is what removes the lake's oldest failure — readers seeing a half-written table — and it makes deletes and updates expressible without rewriting everything. Because the metadata is the table, its maintenance becomes something you have to run.
Full entry →Snapshot isolation
your transaction sees the database frozen as of the instant it began, no matter what commits while it runs.
A level where every read comes from a consistent point-in-time snapshot, implemented with MVCC. Readers never block writers and writers never block readers, which is why it is the workhorse of modern databases. It still allows write skew, so it is not serialisable no matter what the level is named in your engine.
Full entry →