perf(dictionary): a search finds keys by their first characters, indexed

A search matched LIKE '%|eat%' over every entry's barred keys, which no
index can answer, so each one read the whole dictionary: 43-57 ms in
JMdict's 218,863 entries. dictionary_search_key holds a row per key and
loose key with its first one, two and three characters in columns of
their own and one index on them, so the keys a query starts are an
equality the index answers whatever the database's collation (Serverpod's
models can't declare COLLATE "C" or text_pattern_ops). A search now takes
5-26 ms, at 1.4 million rows and 190 MB for JMdict, and its load takes
72 s instead of 33 s.

The loader fills the table beside the entries and loads a dictionary
again when it has none. Until then, in the minutes after the deploying
server starts, the search reads the barred keys as before; those columns
stay until a later release, since the server before a deploy's switch
still searches them. The migration only creates the table and its index.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
This commit is contained in:
Tizian 「ティツィアーン」 2026-10-17 13:22:24 +02:00
commit 8e3a4e56dc
Signed by: raisondetredev
GPG key ID: 07F6FCF405488B64

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