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reverse-engineering-anything/docs/guides/data
3230f50b16 feat(sqlite)!: page selected rows with a stated order and row offset (#9331)
* feat(sqlite): page selected rows with a stated order and row offset

readRows read `NOT INDEXED LIMIT ?` with no ORDER BY and reported
order: "unspecified", so an agent could not reach rows past row_limit
deterministically: raising row_limit hits the fixed 16 MiB reply budget,
and the sampled order depends on whichever index SQLite happened to scan.

Read the window in a unique, stated order and expose the position:

- rowid tables order by rowid unless all of rowid, _rowid_ and oid are
  declared columns, in which case the order stays unspecified.
- WITHOUT ROWID tables order by the primary-key columns, reusing each
  key's DESC flag and declared collation from pragma_index_xinfo so the
  plan keeps index order instead of materialising a sorter.
- rows.order, rows.row_offset and rows.next_row_offset report the window;
  next_row_offset is null once the window reaches the end.
- row_offset (CLI --row-offset) requires table and defaults to 0. A
  non-zero offset is refused when the table declares no usable order,
  because the skipped prefix would be arbitrary.

The schema now checks next_row_offset against truncated and the offset so
a worker reply cannot claim a page it did not read.

One attribution fix came with it: adding ORDER BY text can push an
over-wide projection past SQLite's SQL-text limit, which fails as
SQLITE_TOOBIG before the result-column limit is reported. Attribute that
case to column capacity too, so a 250k-column request still reads as
capacity rather than a byte budget.

Verified: npm run check:fast, npm run format:check on the touched files,
npm run verify:module-boundaries, npm run docs:check, and 196 tests
across the sqlite boundary, application and CLI/MCP suites. A 1002-row
inspection and in-memory EXPLAIN QUERY PLAN checks confirmed the
WITHOUT ROWID path adds no sorter. Full check:pr and the complete test
suite were not run.

* fix(sqlite): resolve the rowid alias and keep paging claims reachable

Three defects in the row paging added alongside row_offset:

- readRowOrder emitted ORDER BY rowid for every rowid table, but a table
  that declares a rowid column shadows that spelling, so the sort used the
  stored column and could repeat or drop rows across pages. Order now names
  the first alias the table leaves unbound, read from raw name bytes so an
  unrelated malformed identifier is not decoded just to choose an order.

- The inventory projection could hide the primary key a WITHOUT ROWID table
  orders by, silently degrading a paginated read to unspecified order. The
  order key is now read from the table itself rather than from the columns
  the caller asked to see.

- A truncated table with no stated order reported a next_row_offset that the
  row_offset rule then refused. It is null there, and the reply limitation
  no longer claims an unspecified order for windows that have one.

rowEvaluationFailure also probed the first rows of the table instead of the
requested window, so a failure confined to a later page was attributed to
columns that evaluate fine there.

* test(sqlite): assert the concatenated pages

The paging regression checked only counts, offsets and flags, so a second
page that repeated the first page's rows would still pass. Assert the values
read across all three pages instead.

* fix(sqlite): decode row keys in the database encoding

readRowKeyFacts decoded primary-key names as UTF-8 and probed a fixed
hidden set, so two supported schemas could not be paged at all:

- A UTF-16 database stores key names as UTF-16 bytes, so "k" decoded to
  NUL-padded text and ORDER BY named an identifier that does not exist.
  Pass the detected encoding, as readColumns and the index-metadata path
  already do.
- A virtual generated column named rowid (hidden=2) was absent from the
  shadow check, so ORDER BY rowid evaluated the generated expression
  instead of the rowid and could sort non-uniquely or fail outright.
  Include generated columns in the alias probe.

Also stop decoding primary-key names for rowid tables: their ORDER BY
names an alias, never a declared key, so an unselected malformed key
name could abort an otherwise readable selection.

The page-concatenation assertion now narrows SqliteValue before reading
.value, which the null/blob arms do not carry; this was failing the
Static checks typecheck job.

* fix(sqlite): order WITHOUT ROWID rows by the index's own key sequence

`readRowOrder` filed `pragma_index_xinfo` key terms into a map keyed by
column name, so a valid composite key that repeats a column —
`PRIMARY KEY(a COLLATE BINARY, a COLLATE NOCASE DESC)` — collapsed to one
term. The generated clause then overstated uniqueness: it omitted the
BINARY term, so `A`/`a` ties survived, and the `row_offset` paging
advertised a `primary_key` order that the actual key does not establish.

Build the terms from the index rows in `seqno` order instead, keeping
repetitions, and bail to `unspecified` if any declared key column never
appears in the index. The declared collation stays explicit so a caller
column's own collation cannot re-sort the window.

Verified against a real SQLite database that the repeated key is accepted
and that the old clause orders A, a, B while the index orders A, B, a.

* fix(sqlite): accept a null next offset on unordered truncated rows

readRows already withholds next_row_offset when a table shadows rowid, _rowid_ and oid and declares no primary key, because every non-zero offset is refused there. The reply schema still required the offset whenever truncated was set, so the provider rejected its own worker result and the first sample never reached CLI or MCP. Require the offset only when the order is stated.

* fix(sqlite): probe row keys only for ordinary tables and name row_offset

readRowKeyFacts ran for a selected virtual shadow table before readRows
could reject it, so an unavailable module surfaced as SQLite's
"no such module" instead of the selection refusal. Probe the key only
when the selected kind is an ordinary table and leave the order
unspecified otherwise, since no rows are read for that kind.

The unordered-offset refusal also reported the generic selection reason,
which callers see against table. Give it its own reason so the failure is
attributed to row_offset.

* feat(sqlite)!: page selected rows with a stated order and row offset

Selected-row inspection currently reports only rows.order: "unspecified" and
offers no way to reach rows past the first sample deterministically. Main also
refuses non-zero row_offset today, so nothing relies on that omission; this
change makes the stated order and the offset the contract, reports the next
offset the caller feeds back, and keeps the existing byte, heap, statement and
deadline limits.

BREAKING CHANGE: rows.order becomes rowid | primary_key | unspecified, and
rows gains required row_offset and next_row_offset members. A client that
validates selected-table output against the previous schema (where order was
the only permitted value) rejects a now-valid reply. Migration: accept the two
new members and treat order: "rowid" | "primary_key" as the stated order the
offset applies to; a null next_row_offset means the window reached the end.

* docs(sqlite): say a null next offset also means no stated order

The selected-rows limitation described next_row_offset as null only when the window reached the end. An unordered table whose row_limit truncates the sample also publishes null, because an offset there would name a request the row-offset rule refuses, so the Evidence read as if the sample were complete. State the second cause and pin it in the existing regression.

* test(sqlite): drop the limitation wording assertion and state the unordered exception

The boundary test pinned the sentence a caller reads in `limitations`,
so a harmless rewrite of that text failed a paging test whose real
subject is `order`, `truncated` and `next_row_offset`.
docs/development/testing.md asks for facts over frozen explanatory prose,
and the three structured expectations already fail if the paging fact
changes.

The tool contract promised that retained rows always have a unique order
and can be paged. A rowid table that shadows rowid, _rowid_ and oid and
declares no primary key has no such order: it returns
order=unspecified with a null next offset and refuses a non-zero
row_offset. Say so in the description so callers do not plan a
continuation the tool always refuses.

* docs(sqlite): say unordered tables cannot be paged

The description told callers that a truncated table without a stated order
needs "the table read without offsets", but omitting row_offset starts at
zero again: with an unchanged row_limit the next call repeats the first
sample instead of continuing past it. Say that these tables cannot be
paged and point at row_limit for a larger first sample.

* style(cli): wrap the native data type path description

The `inspect-native-data-type` argument description line is 82 columns, over the repository's 80-column `.oxfmtrc.json` limit, so `npm run format:check` fails on main and on every branch merged from it. It came in with #9465 and the following commits to this file did not touch it. Reformat the one call the formatter objects to; no behaviour change.

* fix(sqlite): bound rowid alias comparison by name byte length

readRowKeyFacts decoded every column name before testing it against three short aliases, so a table declaring a multi-megabyte name could exhaust the worker heap even when the caller projected the column away. Reject names that cannot be an alias by their byte length, accounting for the database encoding, before building any string.

---------

Co-authored-by: 2SinceJuly <202121119+2SinceJuly@users.noreply.github.com>
Co-authored-by: morluto <76467478+morluto@users.noreply.github.com>
2026-11-09 21:01:58 +08:00
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