diff --git a/server/src/db/replay.rs b/server/src/db/replay.rs
index 63c8fd9812..2c81f0c37b 100644
--- a/server/src/db/replay.rs
+++ b/server/src/db/replay.rs
@@ -1473,7 +1473,7 @@ mod tests {
                             "| physical_plan | SortExec: [bar@0 ASC]                                                                           |",
                             "|               |   CoalescePartitionsExec                                                                        |",
                             "|               |     ProjectionExec: expr=[bar@0 as bar, tag_partition_by@1 as tag_partition_by, time@2 as time] |",
-                            "|               |       RepartitionExec: partitioning=RoundRobinBatch(8)                                          |",
+                            "|               |       RepartitionExec: partitioning=RoundRobinBatch(4)                                          |",
                             "|               |         IOxReadFilterNode: table_name=table_1, chunks=1 predicate=Predicate                     |",
                             "+---------------+-------------------------------------------------------------------------------------------------+",
                         ],
@@ -1566,11 +1566,11 @@ mod tests {
                             "|               |   CoalescePartitionsExec                                                                        |",
                             "|               |     ProjectionExec: expr=[bar@0 as bar, tag_partition_by@1 as tag_partition_by, time@2 as time] |",
                             "|               |       ExecutionPlan(PlaceHolder)                                                                |",
-                            "|               |         RepartitionExec: partitioning=RoundRobinBatch(8)                                        |",
+                            "|               |         RepartitionExec: partitioning=RoundRobinBatch(4)                                        |",
                             "|               |           DeduplicateExec: [tag_partition_by@1 ASC,time@2 ASC]                                  |",
                             "|               |             SortExec: [tag_partition_by@1 ASC,time@2 ASC]                                       |",
                             "|               |               IOxReadFilterNode: table_name=table_1, chunks=1 predicate=Predicate               |",
-                            "|               |         RepartitionExec: partitioning=RoundRobinBatch(8)                                        |",
+                            "|               |         RepartitionExec: partitioning=RoundRobinBatch(4)                                        |",
                             "|               |           IOxReadFilterNode: table_name=table_1, chunks=1 predicate=Predicate                   |",
                             "+---------------+-------------------------------------------------------------------------------------------------+",
                         ],
@@ -1587,7 +1587,7 @@ mod tests {
                             "| physical_plan | ProjectionExec: expr=[bar@0 as bar, tag_partition_by@1 as tag_partition_by, time@2 as time]              |",
                             "|               |   CoalesceBatchesExec: target_batch_size=500                                                             |",
                             "|               |     FilterExec: bar@0 <= CAST(10 AS Float64)                                                             |",
-                            "|               |       RepartitionExec: partitioning=RoundRobinBatch(8)                                                   |",
+                            "|               |       RepartitionExec: partitioning=RoundRobinBatch(4)                                                   |",
                             "|               |         IOxReadFilterNode: table_name=table_1, chunks=1 predicate=Predicate exprs: [#bar LtEq Int64(10)] |",
                             "+---------------+----------------------------------------------------------------------------------------------------------+",
                         ],
diff --git a/server/src/utils.rs b/server/src/utils.rs
index 704b8c864d..ba698e4eec 100644
--- a/server/src/utils.rs
+++ b/server/src/utils.rs
@@ -59,7 +59,11 @@ impl TestDbBuilder {
             .object_store
             .unwrap_or_else(|| Arc::new(ObjectStore::new_in_memory()));
 
-        let exec = Arc::new(Executor::new(1));
+        // deterministic thread and concurrency count
+        let mut exec = Executor::new(1);
+        exec.config_mut().set_concurrency(4);
+        let exec = Arc::new(exec);
+
         let metrics_registry = Arc::new(metrics::MetricRegistry::new());
 
         let (preserved_catalog, catalog, replay_plan) = load_or_create_preserved_catalog(