The file was already tight -- freelist 0 pages, and a plain VACUUM reclaimed
nothing -- so the saving had to come from schema rather than compaction.
Profiled with dbstat and measured every step on copies of the live file.
Three changes to Notes, applied 2026-08-07:
- Rebuild as WITHOUT ROWID (-32 MB). The 5-column composite primary key was
stored twice: once in the table, once in a 62 MB autoindex existing only to
map key -> rowid. Keying the table b-tree on the primary key itself drops the
second copy. ix_NoteBlogName01 grows 25 -> 58 MB in exchange, since a
secondary index on such a table carries the whole primary key instead of a
rowid; net -32 MB.
- Drop Notes_idx_06e01ae3 on TimeStamp DESC (-14 MB). Barely earned its keep as
a rowid index and would have cost 58 MB after the conversion, cancelling the
entire exercise. The crawler's only TimeStamp filter (>= 1535778000) excludes
786 of 1,182,333 rows; Rolodex's default Notes sort carries a three-column
tiebreaker forcing a full sort regardless; the reply-matching UPDATE uses
ABS(TimeStamp - ?) <= 5, which no index on the column can serve. Cost is one
path: Rolodex's Notes page with a date-range filter, 60 ms -> 164 ms.
- Null the DatetimeCrawled placeholder (-13 MB). 1,148,077 rows stored the
literal DDL default '2/12/26 12am', a backfill marker rather than a crawl
time. UI-neutral: Rolodex reads the column through DateSql.Sortable, whose
CASE matches neither format, so those rows already rendered as an em dash.
No application code changed. The schema keeps the same tables, columns, types
and constraints; WITHOUT ROWID is a storage-layout change behind the same SQL
surface, and no consumer referenced rowid on Notes.
Verified against all three consumers on the live file: integrity_check ok, row
counts unchanged (1182333 / 22468 / 188620), journal_mode still wal, crawler
INSERT OR IGNORE still dedupes, Rolodex's NoteBlogName filter still uses
ix_NoteBlogName01, and exactly as many rows read as null through Sortable after
the change as before it. TumblThree touches only Blogs, which is untouched.
Deliberately not done: nulling Notes.DateCreated (a further -12 MB). Unlike
DatetimeCrawled its value parses as a real date, so Rolodex displays and sorts
by it; nulling would turn visible dates into em dashes.
Note that DEFAULT '2/12/26 12am' remains on the column, so any writer inserting
a note without naming it reintroduces the placeholder. Consumer-side date
normalisation must stay.
Co-Authored-By: Claude Opus 5 <[email protected]>
Both columns carry the meaning Blogs.IsActive has: 0 = removed by another
tool, anything else (including NULL) = live. Neither exists in the live
TL.db yet, and both are added from outside this crawler, so the code has
to work on databases either side of the change - naming a missing column
is a hard SQLite error.
HasIsActiveColumn asks PRAGMA table_info once per table per database path
and caches it; AndIsActive/WhereIsActive return "COALESCE(IsActive, 1) = 1"
or an empty string. Every read that selects posts or notes now carries the
filter: GetPosts (both branches, including the per-blog count subquery),
GetReplies, GetRepliesWithMissingText, GetRepliesWithFilledText,
GetAllPostTextColumns, GetAllPostsForBlog, GetPost, GetPostByIdAnyBlog,
and the engagement queries that count or join Notes - GetBlogs,
GetBlogsAll and both note-joining variants of GetBlogsForLikes.
The LEFT JOIN Notes in GetPosts is left alone on purpose: nothing is
selected from it and it can neither add nor remove a row.
LegacyPostsDbImporter is left alone too - it reads a foreign legacy
schema.
Writes were already safe and are documented rather than changed: no
INSERT column list names IsActive, no UPDATE sets it, MapPrefixToColumn
cannot map to it, and there is no INSERT OR REPLACE on Posts or Notes for
a column default to be reset by. Re-crawling a removed row refreshes its
content and leaves the flag at 0. As with Blogs, exclusion belongs at
selection, so the update paths stay keyed on rows the caller already
chose.
Verified against three synthetic databases - no IsActive columns, columns
present with a removed post and its notes, and columns present but NULL -
by running every affected reader: the queries are valid in all three, the
removed rows drop out only where the columns exist, NULL reads as live,
and AddPost/AddNote/UpsertPostFromTextFile/UpdatePostContentFields leave
an IsActive = 0 row at 0.
Co-Authored-By: Claude Opus 5 <[email protected]>
Replaces the Blogs.IsDeleted section. Rolodex adds no column of its own;
it reuses the crawler's existing IsActive flag, so removing a blog in the
UI also stops it being collected.
Co-Authored-By: Claude Opus 5 <[email protected]>
TL.db.md documents the live schema: the three content tables and their
row counts, the '.' placeholder convention the crawler writes instead of
NULL, the two incompatible date formats in Blogs.DateAdded, and the
access paths that matter on the 1.19M-row Notes table.
It also covers Blogs.IsDeleted, which Rolodex adds by ALTER TABLE and
this crawler must not write.
The file was sitting untracked next to the database it describes.
Co-Authored-By: Claude Opus 5 <[email protected]>
jimandClaude Opus 5