fix slow search

src/migrations/20250326154214_precomputed_tsvector.sql

@@ -0,0 +1,48 @@
+-- +goose Up
+-- +goose StatementBegin
+
+
+  -- add the precomputed column
+  ALTER TABLE documents ADD COLUMN content_tsv tsvector;
+  
+  -- populate the new column with the initial data
+  UPDATE documents SET content_tsv = to_tsvector('german', content);
+  
+  -- Step 3: Create a trigger function to update the tsvector column upon insert or update
+  CREATE OR REPLACE FUNCTION update_tsvector()
+  RETURNS TRIGGER AS $$
+  BEGIN
+      NEW.content_tsv := to_tsvector('german', NEW.content);
+      RETURN NEW;
+  END;
+  $$ LANGUAGE plpgsql;
+  
+  -- create the trigger on the documents table
+  CREATE TRIGGER documents_tsvector_update
+  BEFORE INSERT OR UPDATE ON documents
+  FOR EACH ROW EXECUTE FUNCTION update_tsvector();
+  
+  -- create an index on the precomputed column for faster searches
+  CREATE INDEX idx_fts_documents ON documents USING GIN(content_tsv);
+
+
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+
+
+  -- drop the trigger that updates the tsvector column
+  DROP TRIGGER IF EXISTS documents_tsvector_update ON documents;
+  
+  -- Step 2: Drop the trigger function
+  DROP FUNCTION IF EXISTS update_tsvector();
+  
+  -- Step 3: Drop the tsvector column
+  ALTER TABLE documents DROP COLUMN IF EXISTS content_tsv;
+  
+  -- Step 4: Drop the index on the tsvector column
+  DROP INDEX IF EXISTS idx_fts_documents;
+
+
+-- +goose StatementEnd