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# Which Problems Are Solved
Login V2 `ListUsers` lookups of the form username OR email (and email OR
phone) hash-join the full `users14` / `users14_humans` tables, then
filter. That cost grows with instance size (~40ms at 10k users, ~650ms
at 200k).
Top-level login-name equals already used an indexed join, but the same
login-name filter inside an `OrQuery` fell back to the slow view-based
exists query.
# How the Problems Are Solved
**TL;DR:** equality lookups on username, email, phone, or login name
become `INNER JOIN (UNION of indexed ID seeks) AS matches`. Mixed /
contains / name searches keep the old WHERE shape.
### Reviewer map
| Read first | Why |
| --- | --- |
| `internal/query/user_login_equality.go` | Typed filters + extractor +
UNION join |
| `internal/query/user.go` (`prepareUsersQuery`, constructors) | Wiring;
username/email/phone equals return `lowerEqualsFilter` |
| `cmd/setup/76.go` + `cmd/setup/76/*.sql` | Concurrent indexes for
existing deployments; drop invalid leftovers |
| `internal/query/projection/user.go` | Same indexes in `Init()` for new
databases |
| `internal/query/user_login_name_exists_test.go` | SQL-shape coverage |
| `internal/api/grpc/user/v2/integration_test/query_test.go` | Nested
username AND/OR user results |
### Query rewrite
- Extract one equals leaf, a flat `OrQuery` of those leaves, or the same
nested under `AndQuery`. Remaining AND conjuncts stay as WHERE. Equality
nested under `OrQuery` / `NotQuery` is left as WHERE.
- Login-name equals is a UNION arm that reuses `login_names3_users` SQL,
so it works inside OR as well as at the top level.
- EQUALS seeks use `LOWER(col)` for the index, then recheck `col =
value` so case-sensitive searches do not match extra rows.
EQUALS_IGNORE_CASE is unchanged.
- Empty OR arms are not skipped (that would change OR meaning); mixed
empty-OR falls back to WHERE. Login UI already omits empty arms.
### Indexes
- Setup 76: `CREATE INDEX CONCURRENTLY IF NOT EXISTS` on
`users14_username_lower_idx` `(instance_id, LOWER(username))` and
`users14_humans_phone_lower_idx` `(instance_id, LOWER(phone))`. Not
wrapped in a transaction.
- Before create, drop any leftover `pg_index.indisvalid = false` indexes
of those names (failed/cancelled `CREATE INDEX CONCURRENTLY`). `IF NOT
EXISTS` would otherwise skip rebuild.
- `Init()` creates the same indexes without `CONCURRENTLY` (empty
tables). Existing `users14_username` and email lower indexes are
unchanged.
# Additional Changes
- Unit tests assert UNION SQL for username OR email, email OR phone,
login name OR email, username OR username, nested `AndQuery(loginName,
org)`, and nested `AndQuery(Or(...), org)`; that contains / display-name
/ mixed OR / nested `OrQuery(AndQuery(...), ...)` do not UNION; that
email EQUALS rechecks the raw column; and that empty-OR is not
extracted.
- Setup 76 sqlmock coverage: missing `users14` skips work; valid/absent
indexes only create; invalid leftover username index is dropped then
both creates run.
- `TestServer_ListUsers_UsernameAndOr` checks live results: org AND
(alice OR bob) returns both users, sibling username AND is empty, nested
`AndQuery(Or(...), org)` returns both.
# Additional Context
- Base branch: `main`
- Extends the login-name equals rewrite from #12460 to
username/email/phone OR trees used by Login V2 search.
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Co-authored-by: Cursor Agent <[email protected]>
Co-authored-by: Silvan <[email protected]>
684de2e691
