diff --git a/defaults/main.yaml b/defaults/main.yaml
index 1d4630c..fed07ab 100644
--- a/defaults/main.yaml
+++ b/defaults/main.yaml
@@ -47,9 +47,9 @@ postgresql_default_parameters:
   dynamic_shared_memory_type: 'posix'
   max_worker_processes: '{{ ansible_processor_vcpus }}'
   max_parallel_workers: '{{ ansible_processor_vcpus }}'
-  max_parallel_workers_per_gather: '{{ (ansible_processor_vcpus / 2) | round | int }}'
-  max_parallel_maintenance_workers: '{{ (ansible_processor_vcpus / 2) | round | int }}'
-  work_mem: '{{ (((ansible_memory_mb.real.total - ((ansible_memory_mb.real.total * 0.25) | round | int)) / (postgresql_max_connections | int * 3) / ((ansible_processor_vcpus / 2) | round | int)) + 4) | round | int }}MB'
+  max_parallel_workers_per_gather: '{{ ((ansible_processor_vcpus / 2) | round | int) if ansible_processor_vcpus > 1 else ansible_processor_vcpus }}'
+  max_parallel_maintenance_workers: '{{ ((ansible_processor_vcpus / 2) | round | int) if ansible_processor_vcpus > 1 else ansible_processor_vcpus }}'
+  work_mem: '{{ (((ansible_memory_mb.real.total - ((ansible_memory_mb.real.total * 0.25) | round | int)) / (postgresql_max_connections | int * 3) / (((ansible_processor_vcpus / 2) | round | int) if ansible_processor_vcpus > 1 else ansible_processor_vcpus)) + 4) | round | int }}MB'
   maintenance_work_mem: '{{ (ansible_memory_mb.real.total * 0.0625) | round | int }}MB'
   effective_cache_size: '{{ (ansible_memory_mb.real.total * 0.8) | round | int }}MB'
   random_page_cost: "{{ '1.1' if postgresql_storage_type == 'ssd' else '4' }}"