Cloudflare halves DNS build delay, cuts memory use by 85%
A new targeted build planner skips full zone rebuilds for most DNS changes, cutting median propagation delay from 7.7 seconds to 3.3 seconds and peak memory by 85%.
Cloudflare has rebuilt the pipeline that turns a DNS record or zone setting change into data for its authoritative servers, cutting both the time and the memory it takes. The new “Zone Builder” planner picks the smallest of five build types it can prove is byte-for-byte identical to what a full rebuild would produce: resources only, resources plus metadata, apex plus metadata, a purge, or a full zone. Previously, any zone-setting change forced a full rebuild, even for zones with tens of millions of records.
Measured over 24 hours against a mirror pipeline: full builds dropped by about 40%, peak memory fell from 79 GiB to 12 GiB, and the median time from a change to the Zone Builder finishing fell from about 7.7 seconds to 3.3 seconds. The worst-case delay spike dropped from 14.6 minutes to 1.21 minutes. 92.95% of builds now skip rebuilding the whole zone entirely.
Why it matters: if you change a DNS record or zone setting through Cloudflare’s API or dashboard, it now reaches the authoritative servers faster, with far less chance of a slow-build spike during a busy period.
The caveat: this measures only the Zone Builder step. How long the change then takes to spread across Cloudflare’s network still varies by location, and the post doesn’t put a number on that part.