diff --git a/iox_catalog/src/lib.rs b/iox_catalog/src/lib.rs
index 10b52c18f6..8e42bcad38 100644
--- a/iox_catalog/src/lib.rs
+++ b/iox_catalog/src/lib.rs
@@ -170,8 +170,10 @@ where
     Ok(())
 }
 
-/// Creates or gets records in the catalog for the shared kafka topic, query pool, and sequencers for
-/// each of the partitions.
+/// Creates or gets records in the catalog for the shared kafka topic, query pool, and sequencers
+/// for each of the partitions.
+///
+/// Used in tests and when creating an in-memory catalog.
 pub async fn create_or_get_default_records(
     kafka_partition_count: i32,
     txn: &mut dyn Transaction,
@@ -180,7 +182,8 @@ pub async fn create_or_get_default_records(
     let query_pool = txn.query_pools().create_or_get(SHARED_QUERY_POOL).await?;
 
     let mut sequencers = BTreeMap::new();
-    for partition in 1..=kafka_partition_count {
+    // Start at 0 to match the one write buffer partition ID used in all-in-one mode
+    for partition in 0..kafka_partition_count {
         let sequencer = txn
             .sequencers()
             .create_or_get(&kafka_topic, KafkaPartition::new(partition))
@@ -223,7 +226,10 @@ mod tests {
                     let metrics = Arc::new(metric::Registry::default());
                     let repo = MemCatalog::new(metrics);
                     let mut txn = repo.start_transaction().await.unwrap();
-                    let (kafka_topic, query_pool, _) = create_or_get_default_records(2, txn.deref_mut()).await.unwrap();
+                    let (kafka_topic, query_pool, _) = create_or_get_default_records(
+                        2,
+                        txn.deref_mut()
+                    ).await.unwrap();
 
                     let namespace = txn
                         .namespaces()