Originally published on ColdCaseTech.

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Then vs. Now (News report): Then: Cloudflare announced on 2026-11-02 that a targeted build planner and a new scheduler for its DNS Zone Builder cut peak memory by 85% and halved the time from a DNS change to its data being written to Quicksilver. Now: Cloudflare states that zone setting changes no longer rebuild zones with tens of millions of records, while timestamp-only updates still cause a full build until the caller and its purpose can be identified.

Cloudflare reported on November 2, 2026 that a targeted build planner and a new scheduler for its DNS Zone Builder cut peak memory by 85% and halved the time from a DNS change to its data being written to Quicksilver (Cloudflare). The company set out the work in a blog post that follows its 2022 description of the DNS propagation pipeline (Cloudflare).

The Zone Builder now receives about 700 DNS record changes per second, up from about 250 in 2022, plus about 100 other events such as zone setting changes (Cloudflare). Some zones hold more than 20 million records, and the company expects them to keep growing toward hundreds of millions (Cloudflare).

Key Facts

Item Detail Source
Peak memory Cut by 85% Cloudflare
Change-to-Quicksilver time Halved Cloudflare
Record changes per second About 700 now, about 250 in 2022 Cloudflare
Largest zones More than 20 million records Cloudflare
Build types Five, from resources only to full zone Cloudflare

Timeline

  • 2026-11-02: Cloudflare published its account of the targeted build planner and scheduler for DNS builds (Cloudflare).

Details (as Reported)

A build reads the current database state, converts it into the format used at the edge, and writes any changes to Quicksilver (Cloudflare). According to the company, the original Zone Builder rebuilt the desired state from the current database state and did not need to know why a zone changed (Cloudflare). A full build still reads, encodes and compares every record and holds the whole zone in memory, and for the largest zones the zone does not fit in memory at all (Cloudflare).

The new planner chooses the smallest build the company can prove is safe, and the scheduler combines work for the same zone (Cloudflare). Builds come in five types: resources only, resources and metadata, apex and metadata, purge, and full zone (Cloudflare). The rule is that every key a targeted build writes must be byte-for-byte identical to what a full build would write, and if that cannot be proven the system does a full build (Cloudflare).

To support targeting, the company changed the event producer to include changed zone fields and settings, with previous and new values when available (Cloudflare). Cloudflare stated that the extra memory headroom let it safely shorten waits the pipeline has always needed for resilience (Cloudflare). In 2022, per-record builds were 150 times faster than full builds on average, and 4,250 times faster on a test zone with one million records (Cloudflare).

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What Is Not Yet Confirmed

  • Some database functions only update a timestamp, and Cloudflare stated that such an update still causes a full build until it can identify the caller and its purpose (Cloudflare).
  • Missing details, unknown events, or any change that may affect records anywhere in the zone also lead to a full build, according to Cloudflare (Cloudflare).

Sources

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