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Check-in [3107e23e24]

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Comment:derive: write the cache in place, never a second copy (zit#182)

repocache.store and checkpoint.store concatenated header + body + image into a full resident copy before writing; both now stream the pieces to the file with the checksum folded incrementally, byte-identical output. The clone path frees its view before the reopen builds a second derived state. ZIT_DERIVE_FOOTPRINT reports the derive body's composition. pkgsrc cold open: peak RSS 2.32 GB to 2.07 GB.

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Files: files | file ages | folders
SHA3-256: 3107e23e2485254f883802e9db2d179fe43304c9eb5e9cef569e4194cb46ab53
User & Date: dmestas on 2026-09-09 17:58:02.522
Other Links: manifest | tags
Context
2026-09-09
20:04
derive: a disposition sidecar skips what cannot contribute a record (zit#182)

One bit per log frame in .zit-cache/dispositions: crosslink-relevant or not. A full derive consults it and never reconstructs the file blobs and SUBMANIFEST tree nodes that were most of a wide store's walk; the walk distills a fresh map either way. Same trust tier as the log-scan index: self-checksummed, keyed to a validated log prefix, stamped with the shun fingerprint, absent on any doubt. pkgsrc submanifest cold derive 302 s to 22 s; a consuming derive's body is byte-identical, pinned by test. check-in: a18d2edd67 user: dmestas tags: trunk

17:58
derive: write the cache in place, never a second copy (zit#182)

repocache.store and checkpoint.store concatenated header + body + image into a full resident copy before writing; both now stream the pieces to the file with the checksum folded incrementally, byte-identical output. The clone path frees its view before the reopen builds a second derived state. ZIT_DERIVE_FOOTPRINT reports the derive body's composition. pkgsrc cold open: peak RSS 2.32 GB to 2.07 GB. check-in: 3107e23e24 user: dmestas tags: trunk

14:26
0.3.9: version bump and release notes check-in: c641321230 user: dmestas tags: trunk, version-0.3.9
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