diff --git a/src/core/protocol/commands.rs b/src/core/protocol/commands.rs
index 5d0cc45..5ba9c2e 100644
--- a/src/core/protocol/commands.rs
+++ b/src/core/protocol/commands.rs
@@ -11,6 +11,7 @@ mod list_all_users;
 mod list_databases;
 mod list_privileges;
 mod list_users;
+mod list_valid_name_prefixes;
 mod lock_users;
 mod modify_privileges;
 mod passwd_user;
@@ -29,6 +30,7 @@ pub use list_all_users::*;
 pub use list_databases::*;
 pub use list_privileges::*;
 pub use list_users::*;
+pub use list_valid_name_prefixes::*;
 pub use lock_users::*;
 pub use modify_privileges::*;
 pub use passwd_user::*;
@@ -68,6 +70,7 @@ pub fn create_client_to_server_message_stream(socket: UnixStream) -> ClientToSer
 pub enum Request {
     CheckAuthorization(CheckAuthorizationRequest),
 
+    ListValidNamePrefixes,
     CompleteDatabaseName(CompleteDatabaseNameRequest),
     CompleteUserName(CompleteUserNameRequest),
 
@@ -95,6 +98,7 @@ pub enum Request {
 pub enum Response {
     CheckAuthorization(CheckAuthorizationResponse),
 
+    ListValidNamePrefixes(ListValidNamePrefixesResponse),
     CompleteDatabaseName(CompleteDatabaseNameResponse),
     CompleteUserName(CompleteUserNameResponse),
 
diff --git a/src/core/protocol/commands/list_valid_name_prefixes.rs b/src/core/protocol/commands/list_valid_name_prefixes.rs
new file mode 100644
index 0000000..263de97
--- /dev/null
+++ b/src/core/protocol/commands/list_valid_name_prefixes.rs
@@ -0,0 +1 @@
+pub type ListValidNamePrefixesResponse = Vec<String>;
diff --git a/src/server/session_handler.rs b/src/server/session_handler.rs
index 55a061b..8302d03 100644
--- a/src/server/session_handler.rs
+++ b/src/server/session_handler.rs
@@ -181,6 +181,20 @@ async fn session_handler_with_db_connection(
                 let result = check_authorization(dbs_or_users, unix_user).await;
                 Response::CheckAuthorization(result)
             }
+            Request::ListValidNamePrefixes => {
+                let mut result = Vec::with_capacity(unix_user.groups.len() + 1);
+                result.push(unix_user.username.to_owned());
+
+                for group in unix_user
+                    .groups
+                    .iter()
+                    .filter(|x| *x != &unix_user.username)
+                {
+                    result.push(group.to_owned());
+                }
+
+                Response::ListValidNamePrefixes(result)
+            }
             Request::CompleteDatabaseName(partial_database_name) => {
                 // TODO: more correct validation here
                 if !partial_database_name