diff --git a/CHANGELOG.md b/CHANGELOG.md
index a2f9f46..5e728aa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -62,6 +62,7 @@
 * [BUGFIX] Fixed rollout progress dashboard to include query-scheduler too. #376
 * [BUGFIX] Fixed `-distributor.extend-writes` setting on ruler when `unregister_ingesters_on_shutdown` is disabled. #369
 * [BUGFIX] Upstream recording rule `node_namespace_pod_container:container_cpu_usage_seconds_total:sum_irate` renamed. #379
+* [BUGFIX] Treat `compactor_blocks_retention_period` type as string rather than int.#395
 
 ## 1.9.0 / 2021-05-18
 
diff --git a/cortex/config.libsonnet b/cortex/config.libsonnet
index 6369513..f52b38d 100644
--- a/cortex/config.libsonnet
+++ b/cortex/config.libsonnet
@@ -358,7 +358,7 @@
         ruler_max_rule_groups_per_tenant: 20,
 
         // No retention for now.
-        compactor_blocks_retention_period: 0,
+        compactor_blocks_retention_period: '0',
       },
 
       medium_small_user:: {