diff --git a/backend/app/services/collections/providers/base.py b/backend/app/services/collections/providers/base.py
index d76fb6189..b5d37bf9b 100644
--- a/backend/app/services/collections/providers/base.py
+++ b/backend/app/services/collections/providers/base.py
@@ -1,9 +1,8 @@
 from abc import ABC, abstractmethod
 from typing import Any
 
-from app.crud import DocumentCrud
 from app.core.cloud.storage import CloudStorage
-from app.models import CreationRequest, Collection
+from app.models import CreationRequest, Collection, Document
 
 
 class BaseProvider(ABC):
@@ -32,17 +31,14 @@ def create(
         self,
         collection_request: CreationRequest,
         storage: CloudStorage,
-        document_crud: DocumentCrud,
+        docs_batches: list[list[Document]],
     ) -> Collection:
         """Create collection with documents and optionally an assistant.
 
         Args:
             collection_request: Collection parameters (name, description, document list, etc.)
             storage: Cloud storage instance for file access
-            document_crud: DocumentCrud instance for fetching documents
-            batch_size: Number of documents to process per batch
-            with_assistant: Whether to create an assistant/agent
-            assistant_options: Options for assistant creation (provider-specific)
+            docs_batches: Pre-fetched document batches (DB reads must happen before this call)
 
         Returns:
             llm_service_id: ID of the resource to delete
diff --git a/backend/app/services/llm/chain/executor.py b/backend/app/services/llm/chain/executor.py
index 27ab8de86..29f4fc349 100644
--- a/backend/app/services/llm/chain/executor.py
+++ b/backend/app/services/llm/chain/executor.py
@@ -63,21 +63,21 @@ def _setup(self) -> None:
     def _teardown(self, result: BlockResult) -> dict:
         """Finalize chain record, send callback, and update job status."""
 
-        with Session(engine) as session:
-            if result.success:
-                final = LLMChainResponse(
-                    response=result.response.response,
-                    usage=result.usage,
-                    provider_raw_response=result.response.provider_raw_response,
-                )
-                callback_response = APIResponse.success_response(
-                    data=final, metadata=self._request.request_metadata
+        if result.success:
+            final = LLMChainResponse(
+                response=result.response.response,
+                usage=result.usage,
+                provider_raw_response=result.response.provider_raw_response,
+            )
+            callback_response = APIResponse.success_response(
+                data=final, metadata=self._request.request_metadata
+            )
+            if self._request.callback_url:
+                send_callback(
+                    callback_url=str(self._request.callback_url),
+                    data=callback_response.model_dump(),
                 )
-                if self._request.callback_url:
-                    send_callback(
-                        callback_url=str(self._request.callback_url),
-                        data=callback_response.model_dump(),
-                    )
+            with Session(engine) as session:
                 JobCrud(session).update(
                     job_id=self._context.job_id,
                     job_update=JobUpdate(status=JobStatus.SUCCESS),
@@ -89,9 +89,9 @@ def _teardown(self, result: BlockResult) -> dict:
                     output=result.response.response.output.model_dump(),
                     total_usage=self._context.aggregated_usage.model_dump(),
                 )
-                return callback_response.model_dump()
-            else:
-                return self._handle_error(result.error)
+            return callback_response.model_dump()
+        else:
+            return self._handle_error(result.error)
 
     def _handle_error(self, error: str) -> dict:
         callback_response = APIResponse.failure_response(
@@ -103,13 +103,13 @@ def _handle_error(self, error: str) -> dict:
             f"chain_id={self._context.chain_id}, job_id={self._context.job_id}, error={error}"
         )
 
-        with Session(engine) as session:
-            if self._request.callback_url:
-                send_callback(
-                    callback_url=str(self._request.callback_url),
-                    data=callback_response.model_dump(),
-                )
+        if self._request.callback_url:
+            send_callback(
+                callback_url=str(self._request.callback_url),
+                data=callback_response.model_dump(),
+            )
 
+        with Session(engine) as session:
             update_llm_chain_status(
                 session,
                 chain_id=self._context.chain_id,
diff --git a/backend/app/services/llm/jobs.py b/backend/app/services/llm/jobs.py
index 0e2a983b0..d022a1edb 100644
--- a/backend/app/services/llm/jobs.py
+++ b/backend/app/services/llm/jobs.py
@@ -48,10 +48,6 @@ def start_job(
     job_crud = JobCrud(session=db)
     job = job_crud.create(job_type=JobType.LLM_API, trace_id=trace_id)
 
-    # Explicitly flush to ensure job is persisted before Celery task starts
-    db.flush()
-    db.commit()
-
     logger.info(
         f"[start_job] Created job | job_id={job.id}, status={job.status}, project_id={project_id}"
     )
@@ -89,10 +85,6 @@ def start_chain_job(
     job_crud = JobCrud(session=db)
     job = job_crud.create(job_type=JobType.LLM_CHAIN, trace_id=trace_id)
 
-    # Explicitly flush to ensure job is persisted before Celery task starts
-    db.flush()
-    db.commit()
-
     logger.info(
         f"[start_chain_job] Created job | job_id={job.id}, status={job.status}, project_id={project_id}"
     )
@@ -129,16 +121,14 @@ def handle_job_error(
     callback_response: APIResponse,
 ) -> dict:
     """Handle job failure uniformly — send callback and update DB."""
-    with Session(engine) as session:
-        job_crud = JobCrud(session=session)
-
-        if callback_url:
-            send_callback(
-                callback_url=callback_url,
-                data=callback_response.model_dump(),
-            )
+    if callback_url:
+        send_callback(
+            callback_url=callback_url,
+            data=callback_response.model_dump(),
+        )
 
-        job_crud.update(
+    with Session(engine) as session:
+        JobCrud(session=session).update(
             job_id=job_id,
             job_update=JobUpdate(
                 status=JobStatus.FAILED,