# Search Broken — embedding column not converted to vector type

## Date: 2026-05-12

## Problem
The search fails with this error:
```
operator does not exist: text <=> vector
HINT: No operator matches the given name and argument types. You might need to add explicit type casts.
```

## Root cause
The `NoteEmbedding.embedding` column is still type `text` (old JSON string format), NOT `vector(1536)`.
The Prisma migration marked itself as applied but the actual column type conversion was never executed.
The SQL query tries to use the `<=>` cosine distance operator on a text column, which fails.

## Current state
- pgvector extension IS installed (CREATE EXTENSION worked)
- But the embedding column was NOT converted from text to vector(1536)
- There are 102 rows in NoteEmbedding with JSON string embeddings
- The migration SQL needs to: ALTER COLUMN embedding TYPE vector(1536) using proper casting

## What needs to happen
1. Check the actual column type: SELECT column_name, data_type, udt_name FROM information_schema.columns WHERE table_name = 'NoteEmbedding' AND column_name = 'embedding';
2. The migration SQL must convert the column. The embedding values are stored as JSON strings like "[0.1, 0.2, ...]" — need to strip brackets, then cast to vector.
3. The conversion SQL should be something like:
   ALTER TABLE "NoteEmbedding" ALTER COLUMN embedding TYPE vector(1536) USING embedding::vector(1536);
   OR if stored as JSON string:
   ALTER TABLE "NoteEmbedding" ALTER COLUMN embedding TYPE vector(1536) USING (replace(replace(embedding, '[', ''), ']', ''))::vector(1536);
4. Also check if the tsvector column and trigger on Note table were created properly.
5. The semantic-search.service.ts code uses $queryRawUnsafe with <=> operator — make sure the SQL is correct for pgvector.

## Files to check/fix
- prisma/migrations/20260512120000_pgvector_and_fts_search/migration.sql — the actual migration SQL
- lib/ai/services/semantic-search.service.ts — the search service using vector queries
- lib/ai/services/embedding.service.ts — embedding service
- schema.prisma — NoteEmbedding model