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sql: rewrite scid string literals to use scid() for index support - #9407

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sql: rewrite scid string literals to use scid() for index support#9407
vincenzopalazzo wants to merge 2 commits into
ElementsProject:masterfrom
vincenzopalazzo:claude/eloquent-meitner

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♻️ Re-creation of #8984, which was auto-closed on 2026-08-11 when my fork was detached from the repository network (GitHub cannot reopen PRs closed by a detachment). Branch content is unchanged (head 84562dfed); the previous review discussion remains on #8984.

Confirmed still relevant on master (2026-08-12): plugins/sql.c has no scid() handling, scid string literals still cannot use indexes.

Summary

  • When querying with WHERE in_channel='735095x480x1', the string literal was compared directly against the integer SCID column, forcing SQLite into a full table scan even with an index present
  • Root cause: json_sql() passes user queries directly to sqlite3_prepare_v2() without translating scid string literals to integers
  • Automatically rewrite scid string literals matching NNNxNNNxNNN format to use the scid() function before query execution, so '735095x480x1' becomes scid('735095x480x1') transparently

Fixes #8941
Changelog-Fixed: sql plugin now automatically translates short_channel_id string literals to integers for efficient index usage.

Test plan

  • CI passes
  • Queries like SELECT * FROM forwards WHERE in_channel='735095x480x1' now use indexes
  • Queries already using scid('...') explicitly are left unchanged
  • Non-scid string literals are unaffected

Short channel IDs were stored as TEXT strings (e.g., "735095x480x1") in
SQLite, which prevented efficient use of indexes on SCID columns.  Change
storage to INTEGER (the u64 encoding), using a custom "SCID" column type
so the result-reading code can detect these columns and format them back
as "NNNxNNNxNNN" strings for backward-compatible JSON output.

Add two new SQL functions:
- scid('NNNxNNNxNNN') -> integer: for efficient WHERE clause filtering
- fmt_scid(integer) -> 'NNNxNNNxNNN': for formatting in SQL expressions

Fixes ElementsProject#8941
When users query with WHERE in_channel='735095x480x1', the string
literal is compared directly against the integer SCID column, forcing
SQLite to perform a full table scan even when an index exists.

Automatically rewrite scid string literals (matching NNNxNNNxNNN format)
to use the scid() function before passing the query to SQLite, so
'735095x480x1' becomes scid('735095x480x1'). This allows SQLite to
use indexes on SCID columns transparently.

Queries already using scid() explicitly are detected and left unchanged.

Changelog-Fixed: sql plugin now automatically translates short_channel_id string literals to integers for efficient index usage.
Fixes: ElementsProject#8941
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SQL plugin: translate short_channel_id strings to integers before querying SQLite

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