Memory Diff

What one write actually changed about the store: added, removed, retired.

Why it matters in a memory layer

removed is the field to watch, and it should always be zero. Writes add and retire; nothing legitimate removes. So a non-zero value is either a deletion request or the lost update a background job produces when it writes back without a snapshot — two events that both deserve an alert and are otherwise silent.

Summed over every turn of this course's corpus, removed is 0. That zero is the assertion, which is why it is printed rather than filtered out: a number that is always zero costs nothing to report and is the only warning you will get on the day it is not.

retired is the other useful column — it locates the turns where a belief changed, which is where arbitration decisions live and where a differential diagnosis usually starts.

Connections

Taught in: Memory Observability

Do not confuse with: Memory Observability