Upload And Snapshots

Ingest model

Stratum ingests uncompressed STDF lots into a server-side analytical model. A lot can have one or more snapshots over time as data is reprocessed, corrected, or revised.

What a snapshot means

A snapshot is the saved analytical state for a lot at a point in time.

Use snapshots when you need to:

• compare current results to a prior ingest
• preserve a stable reference for a notebook
• understand whether a result changed because of data, not because of UI actions

Practical guidance

• Use the latest snapshot for normal work.
• Switch to an older snapshot only when you are validating a historical conclusion.
• If a notebook is tied to a historical snapshot, keep that context when sharing the notebook.

Ingest warnings matter

Stratum already warns on a few classes of ingest problems, including:

• heavy rates of not executed test records
• unit or res_scal drift across lots of the same product

These warnings do not always block ingest, but they are signals that cross-lot comparisons may need scrutiny.

When to stop and inspect

Pause before analysis if:

• the lot shows an unusual warning count
• units look inconsistent across lots
• the expected test population is obviously missing
• the lot was reprocessed and your notebook depends on the older view