diff --git a/src/raglite/_eval.py b/src/raglite/_eval.py
index ab2296c..1c93630 100644
--- a/src/raglite/_eval.py
+++ b/src/raglite/_eval.py
@@ -195,6 +195,7 @@ def answer_evals(
     num_evals: int = 100,
     *,
     config: RAGLiteConfig | None = None,
+    max_workers: int | None = None,
 ) -> "pd.DataFrame":
     """Read evals from the database and answer them with RAG."""
     try:
@@ -203,19 +204,50 @@ def answer_evals(
         error_message = "To use the `answer_evals` function, please install the `ragas` extra."
         raise ModuleNotFoundError(error_message) from import_error
 
+    from concurrent.futures import ThreadPoolExecutor, as_completed
+
     # Read evals from the database.
     with Session(create_database_engine(config := config or RAGLiteConfig())) as session:
         evals = session.exec(select(Eval).limit(num_evals)).all()
-    # Answer evals with RAG.
-    answers: list[str] = []
-    contexts: list[list[str]] = []
-    for eval_ in tqdm(evals, desc="Answering evals", unit="eval", dynamic_ncols=True):
+
+    def process_eval(eval_):
+        """Process a single evaluation."""
         chunk_spans = retrieve_context(query=eval_.question, config=config)
         messages = [add_context(user_prompt=eval_.question, context=chunk_spans)]
         response = rag(messages, config=config)
         answer = "".join(response)
+        contexts = [str(chunk_span) for chunk_span in chunk_spans]
+        return eval_, answer, contexts
+
+    # Process evals in parallel
+    answers: list[str] = []
+    contexts: list[list[str]] = []
+    eval_results: list[tuple] = []
+
+    # Use ThreadPoolExecutor for parallel processing
+    with ThreadPoolExecutor(max_workers=max_workers) as executor:
+        future_to_eval = {executor.submit(process_eval, eval_): eval_ for eval_ in evals}
+        
+        # Process completed tasks with progress bar
+        with tqdm(total=len(evals), desc="Answering evals", unit="eval", dynamic_ncols=True) as pbar:
+            for future in as_completed(future_to_eval):
+                try:
+                    eval_, answer, context = future.result()
+                    eval_results.append((eval_, answer, context))
+                    pbar.update(1)
+                except Exception as exc:
+                    eval_ = future_to_eval[future]
+                    print(f'Eval {eval_.question} generated an exception: {exc}')
+                    pbar.update(1)
+
+    # Sort results to maintain original order
+    eval_results.sort(key=lambda x: evals.index(x[0]))
+    
+    # Extract results
+    for eval_, answer, context in eval_results:
         answers.append(answer)
-        contexts.append([str(chunk_span) for chunk_span in chunk_spans])
+        contexts.append(context)
+
     # Collect the answered evals.
     answered_evals: dict[str, list[str] | list[list[str]]] = {
         "question": [eval_.question for eval_ in evals],
diff --git a/src/raglite/_query_adapter.py b/src/raglite/_query_adapter.py
index 47957cc..83220f5 100644
--- a/src/raglite/_query_adapter.py
+++ b/src/raglite/_query_adapter.py
@@ -44,6 +44,7 @@ def update_query_adapter(
     optimize_top_k: int = 40,
     optimize_gap: float = 0.05,
     config: RAGLiteConfig | None = None,
+    max_workers: int | None = None,
 ) -> FloatMatrix:
     """Compute an optimal query adapter and update the database with it.
 
@@ -138,8 +139,11 @@ def update_query_adapter(
     FloatMatrix
         The query adapter.
     """
+    from concurrent.futures import ThreadPoolExecutor, as_completed
+    
     config = config or RAGLiteConfig()
     config_no_query_adapter = replace(config, vector_search_query_adapter=False)
+    
     with Session(engine := create_database_engine(config)) as session:
         # Get random evals from the database.
         chunk_embedding = session.exec(select(ChunkEmbedding).limit(1)).first()
@@ -150,63 +154,113 @@ def update_query_adapter(
         if len(evals) == 0:
             error_message = "First run `insert_evals()` to generate evals."
             raise ValueError(error_message)
-        # Construct the query and target matrices.
-        Q = np.zeros((0, len(chunk_embedding.embedding)))
-        T = np.zeros_like(Q)
-        for eval_ in tqdm(
-            evals, desc="Optimizing evals", unit="eval", dynamic_ncols=True, leave=False
-        ):
-            # Embed the question.
-            q = embed_strings([eval_.question], config=config)[0]
-            # Retrieve chunks that would be used to answer the question.
-            chunk_ids, _ = vector_search(
-                q, num_results=optimize_top_k, config=config_no_query_adapter
-            )
-            retrieved_chunks = session.exec(select(Chunk).where(col(Chunk.id).in_(chunk_ids))).all()
-            retrieved_chunks = sorted(retrieved_chunks, key=lambda chunk: chunk_ids.index(chunk.id))
-            # Skip this eval if it doesn't contain both relevant and irrelevant chunks.
-            is_relevant = np.array([chunk.id in eval_.chunk_ids for chunk in retrieved_chunks])
-            if not np.any(is_relevant) or not np.any(~is_relevant):
-                continue
-            # Extract the positive and negative chunk embeddings.
-            P = np.vstack(
-                [
-                    chunk.embedding_matrix[[np.argmax(chunk.embedding_matrix @ q)]]
-                    for chunk in np.array(retrieved_chunks)[is_relevant]
-                ]
-            )
-            N = np.vstack(
-                [
-                    chunk.embedding_matrix[[np.argmax(chunk.embedding_matrix @ q)]]
-                    for chunk in np.array(retrieved_chunks)[~is_relevant]
-                ]
-            )
-            # Compute the optimal target vector t for this query embedding q.
-            t = _optimize_query_target(q, P, N, α=optimize_gap)
-            Q = np.vstack([Q, q[np.newaxis, :]])
-            T = np.vstack([T, t[np.newaxis, :]])
-        # Normalise the rows of Q and T.
-        Q /= np.linalg.norm(Q, axis=1, keepdims=True)
-        if config.vector_search_distance_metric == "cosine":
-            T /= np.linalg.norm(T, axis=1, keepdims=True)
-        # Compute the optimal unconstrained query adapter M.
-        n, d = Q.shape
-        M = (1 / n) * T.T @ Q
-        if n < d or np.linalg.matrix_rank(Q) < d:
-            M += np.eye(d) - Q.T @ np.linalg.pinv(Q @ Q.T) @ Q
-        # Compute the optimal constrained query adapter A* from M, given the distance metric.
-        A_star: FloatMatrix
-        if config.vector_search_distance_metric == "dot":
-            # Use the relaxed Procrustes solution.
-            A_star = M / np.linalg.norm(M, ord="fro") * np.sqrt(d)
-        elif config.vector_search_distance_metric == "cosine":
-            # Use the orthogonal Procrustes solution.
-            U, _, VT = np.linalg.svd(M, full_matrices=False)
-            A_star = U @ VT
-        else:
-            error_message = f"Unsupported metric: {config.vector_search_distance_metric}"
-            raise ValueError(error_message)
-        # Store the optimal query adapter in the database.
+
+    def process_eval(eval_):
+        """Process a single evaluation to compute query and target vectors."""
+        # Create a new session for this thread
+        with Session(create_database_engine(config)) as thread_session:
+            try:
+                # Embed the question.
+                q = embed_strings([eval_.question], config=config)[0]
+                
+                # Retrieve chunks that would be used to answer the question.
+                chunk_ids, _ = vector_search(
+                    q, num_results=optimize_top_k, config=config_no_query_adapter
+                )
+                retrieved_chunks = thread_session.exec(
+                    select(Chunk).where(col(Chunk.id).in_(chunk_ids))
+                ).all()
+                retrieved_chunks = sorted(retrieved_chunks, key=lambda chunk: chunk_ids.index(chunk.id))
+                
+                # Skip this eval if it doesn't contain both relevant and irrelevant chunks.
+                is_relevant = np.array([chunk.id in eval_.chunk_ids for chunk in retrieved_chunks])
+                if not np.any(is_relevant) or not np.any(~is_relevant):
+                    return None  # Skip this eval
+                
+                # Extract the positive and negative chunk embeddings.
+                P = np.vstack(
+                    [
+                        chunk.embedding_matrix[[np.argmax(chunk.embedding_matrix @ q)]]
+                        for chunk in np.array(retrieved_chunks)[is_relevant]
+                    ]
+                )
+                N = np.vstack(
+                    [
+                        chunk.embedding_matrix[[np.argmax(chunk.embedding_matrix @ q)]]
+                        for chunk in np.array(retrieved_chunks)[~is_relevant]
+                    ]
+                )
+                
+                # Compute the optimal target vector t for this query embedding q.
+                t = _optimize_query_target(q, P, N, α=optimize_gap)
+                return q, t
+                
+            except Exception as e:
+                print(f"Error processing eval {eval_.question}: {e}")
+                return None
+
+    # Process evaluations in parallel
+    results = []
+    
+    with ThreadPoolExecutor(max_workers=max_workers) as executor:
+        # Submit all tasks with their original index
+        future_to_eval_idx = {
+            executor.submit(process_eval, eval_): (eval_, idx) 
+            for idx, eval_ in enumerate(evals)
+        }
+        
+        # Process completed tasks with progress bar
+        with tqdm(total=len(evals), desc="Optimizing evals", unit="eval", dynamic_ncols=True, leave=False) as pbar:
+            for future in as_completed(future_to_eval_idx):
+                try:
+                    result = future.result()
+                    if result is not None:  # Only add valid results
+                        eval_, idx = future_to_eval_idx[future]
+                        results.append((idx, result))
+                    pbar.update(1)
+                except Exception as exc:
+                    eval_, idx = future_to_eval_idx[future]
+                    print(f'Eval {eval_.question} generated an exception: {exc}')
+                    pbar.update(1)
+
+    # Extract Q and T matrices from results (maintaining original order)
+    if not results:
+        raise ValueError("No valid evaluations were processed.")
+    
+    # Sort by original index to maintain order
+    results.sort(key=lambda x: x[0])
+    
+    Q = np.vstack([result[1][0][np.newaxis, :] for result in results])
+    T = np.vstack([result[1][1][np.newaxis, :] for result in results])
+    # Ensure arrays are float32 or float64 for linear algebra operations
+    Q = Q.astype(np.float32)
+    T = T.astype(np.float32)
+    # Normalise the rows of Q and T.
+    Q /= np.linalg.norm(Q, axis=1, keepdims=True)
+    if config.vector_search_distance_metric == "cosine":
+        T /= np.linalg.norm(T, axis=1, keepdims=True)
+    
+    # Compute the optimal unconstrained query adapter M.
+    n, d = Q.shape
+    M = (1 / n) * T.T @ Q
+    if n < d or np.linalg.matrix_rank(Q) < d:
+        M += np.eye(d) - Q.T @ np.linalg.pinv(Q @ Q.T) @ Q
+    
+    # Compute the optimal constrained query adapter A* from M, given the distance metric.
+    A_star: FloatMatrix
+    if config.vector_search_distance_metric == "dot":
+        # Use the relaxed Procrustes solution.
+        A_star = M / np.linalg.norm(M, ord="fro") * np.sqrt(d)
+    elif config.vector_search_distance_metric == "cosine":
+        # Use the orthogonal Procrustes solution.
+        U, _, VT = np.linalg.svd(M, full_matrices=False)
+        A_star = U @ VT
+    else:
+        error_message = f"Unsupported metric: {config.vector_search_distance_metric}"
+        raise ValueError(error_message)
+    
+    # Store the optimal query adapter in the database.
+    with Session(engine := create_database_engine(config)) as session:
         index_metadata = session.get(IndexMetadata, "default") or IndexMetadata(id="default")
         index_metadata.metadata_["query_adapter"] = A_star
         flag_modified(index_metadata, "metadata_")
@@ -216,4 +270,5 @@ def update_query_adapter(
             session.execute(text("CHECKPOINT;"))
         # Clear the index metadata cache to allow the new query adapter to be used.
         IndexMetadata._get.cache_clear()  # noqa: SLF001
+    
     return A_star