Read historical state

Goal. Find out what a value used to be. About a minute.

You need. A key that has been written more than once.

See the versions

strata ./shop kv history price

VERSION  COMMITTED_AT                    VALUE
      5  2026-09-14 17:29:28.241408 UTC  200
      4  2026-09-14 17:29:28.218256 UTC  150
      3  2026-09-14 17:29:28.195333 UTC  100

Newest first. Two independent ways to name a moment sit in that table, and they are not interchangeable.

Read at a version

strata ./shop kv get price --as-of 3

100

--as-of takes the number from the VERSION column: a position on the commit timeline, not a date.

Read at a time

strata ./shop kv get price --as-of-time '2026-09-14 17:29:28.20Z'

100

--as-of-time takes a real moment, and resolves to the commit at or before it. It accepts a date, a date and time, an offset-bearing timestamp, or raw epoch microseconds.

Passing both fails rather than picking one:

invalid_argument.executor.as_of_conflict: as_of and as_of_time are mutually
exclusive

It works across the models

The same two flags are on reads throughout, not just key-value:

strata ./shop json get config '$.stocks' --as-of 9
strata ./shop graph bfs social alice --as-of 9

For a listing that spans several pages, pass the same --as-of to every page. That is what makes an enumeration describe one instant rather than a moving target.

What just happened

Nothing was restored and nothing moved. A historical read is a read: the current state is untouched, and no branch was created. That is the difference between this and Fork from historical state, which is what you want if you intend to work from the past rather than look at it.

Failure modes

history_unavailable.engine.persistence_history. The point you asked for is outside what the database retains, most often because a wall-clock instant was passed to --as-of, which wants a version. Take the number from the table.

A read returns nothing rather than erroring. A version used where a timestamp belongs can land on a real but wrong position. In a fresh database the two numbers are equal so the mistake works; in a cloned one they differ.

Next

Fork from historical state.