Timeline

The image carries the active tag set now -- name, tagtype, optional value, per rid -- so tagsOf, branches, tagNamesMatching and activeTagValue all answer from either backing. Stored resolved: the derive has applied §5.1's cancel rule and §5.3's precedence before serialize runs, so nothing here re-judges either. That is what fossil does, where tagxref holds one row per (rid, tag) with propagation flattened in by tag_propagate at write time.

It subsumes the §5.2 override columns from the previous change; those are gone rather than kept beside a general mechanism that already holds the same bytes.

Two readers still went straight to tagxref and had to be routed: activeBranchValue and hasActiveClosed. Both answered plausibly on an image rather than refusing -- the first as a null-deref in a postcondition under safety and, with that assert compiled out, a different branch listing; the second as a listing quietly missing every (closed) marker.

tagNamesMatching keeps a per-backing arm on purpose. The derive holds a (rid, tag) map with no per-rid index, so walking rids and asking each for its tags is O(rids x map) there; sharing one loop cost 42s where two cost 0.37s. check-in: ce9e7a1cd4 user: dmestas tags: trunk

The default listing prints an ID per check-in and reads nothing else, yet it reconstructed and re-parsed every reachable manifest to find P cards. On a repository whose manifests inline the whole file set -- sqlite's are 2,219 F cards and 186KB each -- that is 6GB of text decompressed and parsed to answer a question that reads none of it.

Fossil does not do this. manifest_crosslink parses a manifest once and writes the edge to a persistent table:

CREATE TABLE plink(pid, cid, isprim, mtime, baseid, UNIQUE(pid,cid)); CREATE INDEX plink_i2 ON plink(cid,pid);

Every later traversal is an indexed read of it -- timeline.c's ancestor walk is a recursive CTE over plink and touches no manifest. The tell is fossil's parsed-manifest cache: MX_MANIFEST_CACHE is 6, and its comment says it exists for rebuild. Nothing on the read path needed more.

zit's derive holds the same relation, with the is_primary flag plink's isprim carries, and since #98 the zero-parse image carries it too, so this walk reads no artifact content at all. --long still needs D/U/C, so it stays on the reading walk.

log tip, min of repeated runs, warm, ReleaseFast:

libfossil 1.28s -> 0.02s libspatialite 4.81s -> 0.00s fossil 20.40s -> 0.11s tcl 40.05s -> 0.65s sqlite 62.90s -> 0.51s

Output byte-identical across all seven corpora.

WHAT MOVED: the reading walk re-hashed and re-validated every reachable artifact, so log doubled as an integrity check. It no longer does -- which is fossil's split, where validation happens at crosslink and test-integrity re-checks. zit verify is that verb, and the wrong-full-ID test now asserts verify catches what log stopped catching, so the coverage cannot go missing unnoticed. check-in: cc996c1af2 user: dmestas tags: trunk