feat: pgvector - make error messages more informative (#1684)

* Include the actual SQL exception when reporting the error.

* small improvements

---------

Co-authored-by: Stefano Fiorucci <[email protected]>

Author: superkelvint

README.md

@@ -89,6 +89,7 @@ GitHub. The GitHub Actions workflow will take care of the rest.
     ```
 3. Wait for the CI to do its magic
 4. Review the changelog PR
+
     If the release is successful, the HaystackBot will open a pull request to generate the changelog. 
     Add yourself as the reviewer. If there are any issues, edit the changelog manually.
 

integrations/pgvector/src/haystack_integrations/document_stores/pgvector/document_store.py

@@ -276,7 +276,9 @@ def _execute_sql(
             result = cursor.execute(sql_query, params)
         except Error as e:
             self._connection.rollback()
-            detailed_error_msg = f"{error_msg}.\nYou can find the SQL query and the parameters in the debug logs."
+            detailed_error_msg = (
+                f"{error_msg}. Error: {e!r}. \nYou can find the SQL query and the parameters in the debug logs."
+            )
             raise DocumentStoreError(detailed_error_msg) from e
 
         return result
@@ -314,7 +316,9 @@ async def _execute_sql_async(
             result = await cursor.execute(sql_query, params)
         except Error as e:
             await self._async_connection.rollback()
-            detailed_error_msg = f"{error_msg}.\nYou can find the SQL query and the parameters in the debug logs."
+            detailed_error_msg = (
+                f"{error_msg}. Error: {e!r}. \nYou can find the SQL query and the parameters in the debug logs."
+            )
             raise DocumentStoreError(detailed_error_msg) from e
 
         return result
@@ -795,7 +799,7 @@ def write_documents(self, documents: List[Document], policy: DuplicatePolicy = D
         except Error as e:
             self._connection.rollback()
             error_msg = (
-                "Could not write documents to PgvectorDocumentStore. \n"
+                f"Could not write documents to PgvectorDocumentStore. Error: {e!r}. \n"
                 "You can find the SQL query and the parameters in the debug logs."
             )
             raise DocumentStoreError(error_msg) from e
@@ -852,7 +856,7 @@ async def write_documents_async(
         except Error as e:
             await self._async_connection.rollback()
             error_msg = (
-                "Could not write documents to PgvectorDocumentStore. \n"
+                f"Could not write documents to PgvectorDocumentStore. Error: {e!r}. \n"
                 "You can find the SQL query and the parameters in the debug logs."
             )
             raise DocumentStoreError(error_msg) from e