pub const EDGES: usize = 90;Expand description
Edge assertions (bulk_import).
Per-row cost on this path rises with the size of links_current, not
with the chunk (D-059) — so cutting the chunk buys latency and costs
throughput, ~11% for 1,000 edges. An earlier version of this comment
claimed it was 3.3× faster; that came from multiplying eleven copies of
a chunk measured into an empty database.
This size does not meet the 3 ms bound on a populated database. 90 edges into an 8,000-edge table take 9.06 ms — measured, two sessions at 9.08 and 9.05, against an empty-table arm of 2.69 and 2.65 beside them (D-136).
The reason given here until 0.10.0 — that trg_links_single_open’s
EXISTS scans the whole out-degree, “a schema defect with a proven fix,
recorded in D-059 and not applied here” — described 0.5.5. The fix was
applied, as the v5 → v6 rung, and took this from 47.7 ms to ~8 ms.
What survives is the miss, not its cause: the bound is exceeded ~3×, by
something nobody has attributed.
D-134 retired the growth claim on the neighbouring single-assertion path and did not measure this one; D-136 is why this line now carries a measurement rather than a figure quoted from 0.5.6.