feat(rdb): clarify engine expects version name not ID

Author: jremy42

internal/services/rdb/instance.go

@@ -55,16 +55,16 @@ func ResourceInstance() *schema.Resource {
 				Description:      "The type of database instance you want to create",
 				DiffSuppressFunc: dsf.IgnoreCase,
 			},
-			"engine": {
-				Type:             schema.TypeString,
-				Optional:         true,
-				Computed:         true,
-				Description:      "Database's engine version id. Changing this value triggers a blue/green upgrade using MajorUpgradeWorkflow with automatic endpoint migration",
-				DiffSuppressFunc: dsf.IgnoreCase,
-				ConflictsWith: []string{
-					"snapshot_id",
-				},
+		"engine": {
+			Type:             schema.TypeString,
+			Optional:         true,
+			Computed:         true,
+			Description:      "Database's engine version name (e.g., 'PostgreSQL-16', 'MySQL-8'). Changing this value triggers a blue/green upgrade using MajorUpgradeWorkflow with automatic endpoint migration",
+			DiffSuppressFunc: dsf.IgnoreCase,
+			ConflictsWith: []string{
+				"snapshot_id",
 			},
+		},
 			"snapshot_id": {
 				Type:        schema.TypeString,
 				Optional:    true,

templates/resources/rdb_instance.md.tmpl

@@ -174,7 +174,7 @@ interruption.
 
 ~> **Important** Once your Database Instance reaches `disk_full` status, if you are using `lssd` storage, you should upgrade the `node_type`, and if you are using `bssd` storage, you should increase the volume size before making any other changes to your Database Instance.
 
-- `engine` - (Required) Database Instance's engine version (e.g. `PostgreSQL-11`).
+- `engine` - (Required) Database Instance's engine version name (e.g. `PostgreSQL-16`, `MySQL-8`).
 
 ~> **Important** Updates to `engine` will perform a blue/green upgrade using `MajorUpgradeWorkflow`. This creates a new instance from a snapshot, migrates endpoints automatically, and updates the Terraform state with the new instance ID. The upgrade ensures minimal downtime but **any writes between the snapshot and the endpoint migration will be lost**. Use the `upgradable_versions` computed attribute to check available versions for upgrade.