Sandboxing and database branches
Governed database branches, isolated writes, cleanup, and proof that source data stayed untouched.
Seven chapters. One continuous data-boundary story.
The path moves from billion-row governed branching, to 5B scale and the FK gap, then the FK fix, repeat matrix, prepared-pool optimization, GCP Local SSD latency isolation, and cold reserve pools.
The first three reads in this boundary.
These notes give the clearest path from product behavior to measured evidence before the full archive.
Imladri added cold branch pools for governed Postgres sandboxes.
A cold-reserve branchd run over the verified 5B source passed 40/40 direct proof branches and two 500/500 DDL stress runs with 0 source mutations, then exposed the 8-vCPU host as the remaining limitation.
Imladri isolated DB branch latency on GCP Local SSD, then cut the 5B DDL tail.
A focused branchd latency note: 500 sustained 5B DDL-heavy branches on GCP Local SSD, 88.27ms create p95, 361.87ms write p95, 134.52ms destroy p95, and 0 source mutations.
Imladri moved governed Postgres FK branches onto a prepared COW pool.
A prepared copy-on-write branch pool reduced 100-way branch creation to 14.67ms p95, then the external snapshot backend reached 20 concurrent warmed physical branches under six seconds p95 on a real attached Btrfs volume.
Full archive for this boundary.
Imladri re-ran governed Postgres branches at 100M, 1B, and 5B rows.
A repeat multi-scale matrix showed complete numeric coverage, 20 storage-COW branch samples per scale, 0 source mutations, 6/6 proof checks, and a 5B metadata-tail explanation.
Imladri patched branch-local foreign-key actions in governed Postgres sandboxes.
Branch-local FK orphan rejection, restrict, cascade, set-null, set-default, deferred constraints, composite MATCH FULL keys, self-referential FKs, multi-branch checks, and 100-way concurrent FK branches passed with zero source mutations.
Imladri branched a verified 5B-row Postgres source, then found the next database-agent gap.
A focused sandboxing note: 5B-row numeric coverage, 100/100 concurrent branches, 10M branch-local writes, 0 source mutations, and the branch-local orphan FK limitation found before the fix.
Imladri branched governed Postgres sandboxes over 1 billion rows with a 24.07ms p50.
A local Postgres scale run proved exact billion-row coverage, twenty copy-on-write database branches, isolated writes, cleanup, and proof export without mutating the source table.