The previous attempt passed fileLength in the inline config, and the
worker discarded it. sqlite.worker.ts builds the lazy file's config
itself and hardcodes:
fileLength: config.serverMode === "chunked"
? config.databaseLengthBytes
: undefined
So in full mode there is no way to supply a length, and the library
falls back to sizing the file with a HEAD request — which GitHub Pages
answers with the gzipped length, and then refuses to use.
Chunked mode is the only mode that takes a length. One chunk holds the
whole database, so the chunk index is always 0 and every request goes to
urlPrefix + "0"; the assembler therefore publishes <id>.sqlite30. The
length still comes from the range probe, which also checks the bytes are
a SQLite header.
dbPrefixOf and dbOf derive one form from the other and are handed to
RemoteDatabase together, so the prefix the library appends an index to
and the file the assembler writes cannot drift apart. A test pins that;
nothing else would catch it, because the symptom is a 404 per query.
The stray-artifact guard now also rejects a leftover <id>.sqlite3, which
after this change is a stale artifact rather than the published one.
sqlite-wasm-http was checked as an alternative and does not help: its
worker takes the size from a HEAD Content-Length too, and its options
expose no way to override it, so on Pages it would silently use the
compressed size. Its shared-cache backend wants COOP/COEP, but it ships
a fallback that does not, so isolation was never the blocker — the
architecture note claiming otherwise is corrected.
The browser downloaded 45 MB of gzipped SQLite before it could answer
anything. Now sql.js-httpvfs asks for the pages a query touches and the
databases ship uncompressed as <id>.sqlite3 — a byte range of a gzip
stream is not a byte range of a database.
That only works if every query the site issues is index-driven, and
measured against the real 2016 file, most were not:
so_bao_danh = ? SEARCH via PK ~20 KB
ho_ten_ascii LIKE '%x%' SCAN 127 MB
ho_ten_ascii LIKE 'x%' SCAN 127 MB
COUNT(*) covering index scan 20 MB
ORDER BY toan DESC LIMIT 10 SCAN + temp b-tree 127 MB
Prefix LIKE scans because SQLite's LIKE optimisation needs a NOCASE
index; a range comparison does use the index. So the schema changed to
suit the access pattern rather than the search changing to suit the
schema.
name_word holds one row per word of each name, WITHOUT ROWID so the
table is the index, carrying ho_ten_ascii so a multi-word query is
resolved inside a single b-tree. name_word_freq says which word of a
query is rarest — the vocabulary is 4,397 words across 2.87M entries, so
"buu loc" seeks on 287 entries rather than walking the 300,000 that
"thi" would. Searching by any word of a name survives, at a few hundred
KB a query.
idx_ho_ten and idx_ho_ten_ascii are gone: no plan could use either.
Partial indexes on toan, khtn and khxh cost 12 MB and keep the SQL
presets off a full scan. The footer's candidate count now comes from
datasets.json instead of COUNT(*).
2016 grows 223.5 MB to 288.6 MB, 2017 162.7 MB to 237.7 MB, and the site
is 528 MB against the 1 GB GitHub Pages limit. Row counts are unchanged.
The SQL tab is the one place a user can still write a query that reads
the whole table, so it asks before it opens, runs under a byte budget
that stops a runaway query, and shows what each query actually fetched.
Verified: row counts through the assembler guards, every app query
index-driven under EXPLAIN QUERY PLAN, and GitHub Pages returning 206
with a correct Content-Range. Not verified in a browser — this machine
has none — and the library refuses to open a file the host compresses,
so the deployed response headers need a look.
Comments across the tree justified the code by pointing at a Rust
implementation that is no longer in the repository, citing files and line
numbers (config.rs:132, schema.rs:26-54, reader.rs:42) that cannot be
opened, plus crates and datasets that are equally gone. A reader could not
check any of it.
Every invariant those comments carried is kept and restated so it stands on
its own: the bytewise sort that decides which row survives a duplicate exam
number, the literal U+0300..U+036F range that must match the site's toAscii,
the trailing space in "SINH ", the BIFF and shared-string corrections, the
VACUUM-after-COMMIT rule, the deploy-from-main guard.
The reader's contract is now anchored to the frozen oracle in
parser/testdata, which still exists and is still checked, rather than to the
tool that originally produced it.
TestDDLMatchesRust becomes TestDDLIsFrozen: it compares against a copy of
the DDL inside the test and never read schema.rs, so both the name and the
failure message were misleading.
ToAscii no longer claims the d-replacement must precede lowercasing. Both
cases map to 'd' and ToLower runs last, so the order has no effect.
The pipeline is now Go outside web/. differential-parity.mjs becomes
assembler/internal/verify, reachable as `assemble verify A B`. The port fixed a
real weakness: the JavaScript hashed each row's fields joined bare, so a value
shifted across a column boundary produced the same digest. A test now pins that.
The hub still rendered "Phiên bản cũ của trang 2017" above a permanently empty
list — it split datasets on id.includes("old"), and both such datasets are gone.
The heading and the filter are removed. index.html titled every page "THPT QG
2017", including 2016 and the hub, because one file is copied to every route;
the static title is now neutral and the app sets the dataset's own.
Dead code removed: the isOld2/containsOld branches in the stats block, which
only 2017-old2 could ever reach; SUBJECT_LABELS, DATASET_IDS and the unread
`short` subject field; an unused vite.svg and a favicon link to a file that
never existed; two unused CSS rules and --shadow-sm; site.Paths.Root.
Corrected comments that were confidently wrong rather than merely stale: the
reader claimed to be row-streaming when both implementations decode the whole
workbook into memory first, and the fidelity oracle still spoke of 299 input
files when it covers 182. Candidate counts in the hub now derive from
datasets.json instead of being written a second time as prose.
plans/ is emptied. The parity report it held was cited by docs/data-pipeline.md,
so the evidence that the recovered foreign-language scores are real — not the
citation, the four arguments themselves — is now inline there.
Verified: 2017 rebuilt after the writer change hashes identically to the build
before it.
tiennm99