diff --git a/oonipipeline/src/oonipipeline/temporal/common.py b/oonipipeline/src/oonipipeline/temporal/common.py
index f14c9b79..6e497b43 100644
--- a/oonipipeline/src/oonipipeline/temporal/common.py
+++ b/oonipipeline/src/oonipipeline/temporal/common.py
@@ -86,6 +86,7 @@ def maybe_delete_prev_range(db: ClickhouseConnection, prev_range: PrevRange) ->
     if not prev_range.max_created_at or not prev_range.min_created_at:
         return ""
 
+    wait_for_mutations(db, prev_range.table_name)
     # Disabled due to: https://github.com/ClickHouse/ClickHouse/issues/40651
     # db.execute("SET allow_experimental_lightweight_delete = true;")
 
@@ -99,7 +100,6 @@ def maybe_delete_prev_range(db: ClickhouseConnection, prev_range: PrevRange) ->
     q = f"ALTER TABLE {prev_range.table_name} DELETE "
     final_query = q + where
     db.execute(final_query, q_args)
-    wait_for_mutations(db, prev_range.table_name)
     return final_query
 
 
diff --git a/oonipipeline/src/oonipipeline/temporal/workflows/observations.py b/oonipipeline/src/oonipipeline/temporal/workflows/observations.py
index 2916f636..d354149a 100644
--- a/oonipipeline/src/oonipipeline/temporal/workflows/observations.py
+++ b/oonipipeline/src/oonipipeline/temporal/workflows/observations.py
@@ -70,15 +70,10 @@ async def run(self, params: ObservationsWorkflowParams) -> dict:
 
         await workflow.execute_activity(
             optimize_tables,
-            OptimizeTablesParams(
-                clickhouse=params.clickhouse, table_names=["buffer_obs_web"]
-            ),
+            OptimizeTablesParams(clickhouse=params.clickhouse, table_names=["obs_web"]),
             start_to_close_timeout=timedelta(minutes=20),
             retry_policy=RetryPolicy(maximum_attempts=10),
         )
-        workflow.logger.info(
-            f"finished optimize_tables for bucket_date={params.bucket_date}"
-        )
 
         previous_ranges = await workflow.execute_activity(
             get_previous_range,
@@ -89,8 +84,8 @@ async def run(self, params: ObservationsWorkflowParams) -> dict:
                 probe_cc=params.probe_cc,
                 tables=["obs_web"],
             ),
-            start_to_close_timeout=timedelta(minutes=20),
-            retry_policy=RetryPolicy(maximum_attempts=10),
+            start_to_close_timeout=timedelta(minutes=2),
+            retry_policy=RetryPolicy(maximum_attempts=4),
         )
         workflow.logger.info(
             f"finished get_previous_range for bucket_date={params.bucket_date}"
@@ -108,14 +103,6 @@ async def run(self, params: ObservationsWorkflowParams) -> dict:
             f"{total_t.pretty} speed: {obs_res['mb_per_sec']}MB/s ({obs_res['measurement_per_sec']}msmt/s)"
         )
 
-        await workflow.execute_activity(
-            optimize_tables,
-            OptimizeTablesParams(
-                clickhouse=params.clickhouse, table_names=["buffer_obs_web"]
-            ),
-            start_to_close_timeout=timedelta(minutes=20),
-            retry_policy=RetryPolicy(maximum_attempts=10),
-        )
         workflow.logger.info(
             f"finished optimize_tables for bucket_date={params.bucket_date}"
         )