Adds important postgresql note (quay#1131)

Co-authored-by: Steven Smith <[email protected]>

Author: stevsmit

modules/operator-unmanaged-postgres.adoc

@@ -4,6 +4,11 @@
 
 If you are using an externally managed PostgreSQL database, you must manually enable the `pg_trgm` extension for a successful deployment.
 
+[IMPORTANT]
+====
+You must not use the same externally managed PostgreSQL database for both {productname} and Clair deployments. Your PostgreSQL database must also not be shared with other workloads, as it might exhaust the natural connection limit on the PostgreSQL side when connection-intensive workloads, like {productname} or Clair, contend for resources. Additionally, pgBouncer is not supported with {productname} or Clair, so it is not an option to resolve this issue.
+====
+
 Use the following procedure to deploy an existing PostgreSQL database.
 
 .Procedure

modules/unmanaging-clair-database.adoc

@@ -8,6 +8,11 @@
 
 Use the following procedure to set your Clair database to unmanaged.
 
+[IMPORTANT]
+====
+You must not use the same externally managed PostgreSQL database for both {productname} and Clair deployments. Your PostgreSQL database must also not be shared with other workloads, as it might exhaust the natural connection limit on the PostgreSQL side when connection-intensive workloads, like {productname} or Clair, contend for resources. Additionally, pgBouncer is not supported with {productname} or Clair, so it is not an option to resolve this issue.
+====
+
 .Procedure
 
 * In the Quay Operator, set the `clairpostgres` component of the `QuayRegistry` custom resource to `managed: false`: