diff --git a/src/Access/AccessControlManager.cpp b/src/Access/AccessControlManager.cpp
index f8f15e425ed..e2589969fd8 100644
--- a/src/Access/AccessControlManager.cpp
+++ b/src/Access/AccessControlManager.cpp
@@ -42,7 +42,7 @@ public:
 
     std::shared_ptr<const ContextAccess> getContextAccess(
         const UUID & user_id,
-        const std::vector<UUID> & current_roles,
+        const boost::container::flat_set<UUID> & current_roles,
         bool use_default_roles,
         const Settings & settings,
         const String & current_database,
@@ -113,7 +113,7 @@ void AccessControlManager::setDefaultProfileName(const String & default_profile_
 
 std::shared_ptr<const ContextAccess> AccessControlManager::getContextAccess(
     const UUID & user_id,
-    const std::vector<UUID> & current_roles,
+    const boost::container::flat_set<UUID> & current_roles,
     bool use_default_roles,
     const Settings & settings,
     const String & current_database,
@@ -124,21 +124,21 @@ std::shared_ptr<const ContextAccess> AccessControlManager::getContextAccess(
 
 
 std::shared_ptr<const EnabledRoles> AccessControlManager::getEnabledRoles(
-    const std::vector<UUID> & current_roles,
-    const std::vector<UUID> & current_roles_with_admin_option) const
+    const boost::container::flat_set<UUID> & current_roles,
+    const boost::container::flat_set<UUID> & current_roles_with_admin_option) const
 {
     return role_cache->getEnabledRoles(current_roles, current_roles_with_admin_option);
 }
 
 
-std::shared_ptr<const EnabledRowPolicies> AccessControlManager::getEnabledRowPolicies(const UUID & user_id, const std::vector<UUID> & enabled_roles) const
+std::shared_ptr<const EnabledRowPolicies> AccessControlManager::getEnabledRowPolicies(const UUID & user_id, const boost::container::flat_set<UUID> & enabled_roles) const
 {
     return row_policy_cache->getEnabledRowPolicies(user_id, enabled_roles);
 }
 
 
 std::shared_ptr<const EnabledQuota> AccessControlManager::getEnabledQuota(
-    const UUID & user_id, const String & user_name, const std::vector<UUID> & enabled_roles, const Poco::Net::IPAddress & address, const String & custom_quota_key) const
+    const UUID & user_id, const String & user_name, const boost::container::flat_set<UUID> & enabled_roles, const Poco::Net::IPAddress & address, const String & custom_quota_key) const
 {
     return quota_cache->getEnabledQuota(user_id, user_name, enabled_roles, address, custom_quota_key);
 }
@@ -153,7 +153,7 @@ std::vector<QuotaUsageInfo> AccessControlManager::getQuotaUsageInfo() const
 std::shared_ptr<const EnabledSettings> AccessControlManager::getEnabledSettings(
     const UUID & user_id,
     const SettingsProfileElements & settings_from_user,
-    const std::vector<UUID> & enabled_roles,
+    const boost::container::flat_set<UUID> & enabled_roles,
     const SettingsProfileElements & settings_from_enabled_roles) const
 {
     return settings_profiles_cache->getEnabledSettings(user_id, settings_from_user, enabled_roles, settings_from_enabled_roles);
diff --git a/src/Access/AccessControlManager.h b/src/Access/AccessControlManager.h
index 810970a8379..94bc22eb3e5 100644
--- a/src/Access/AccessControlManager.h
+++ b/src/Access/AccessControlManager.h
@@ -2,6 +2,7 @@
 
 #include <Access/MultipleAccessStorage.h>
 #include <Poco/AutoPtr.h>
+#include <boost/container/flat_set.hpp>
 #include <memory>
 
 
@@ -51,24 +52,24 @@ public:
 
     std::shared_ptr<const ContextAccess> getContextAccess(
         const UUID & user_id,
-        const std::vector<UUID> & current_roles,
+        const boost::container::flat_set<UUID> & current_roles,
         bool use_default_roles,
         const Settings & settings,
         const String & current_database,
         const ClientInfo & client_info) const;
 
     std::shared_ptr<const EnabledRoles> getEnabledRoles(
-        const std::vector<UUID> & current_roles,
-        const std::vector<UUID> & current_roles_with_admin_option) const;
+        const boost::container::flat_set<UUID> & current_roles,
+        const boost::container::flat_set<UUID> & current_roles_with_admin_option) const;
 
     std::shared_ptr<const EnabledRowPolicies> getEnabledRowPolicies(
         const UUID & user_id,
-        const std::vector<UUID> & enabled_roles) const;
+        const boost::container::flat_set<UUID> & enabled_roles) const;
 
     std::shared_ptr<const EnabledQuota> getEnabledQuota(
         const UUID & user_id,
         const String & user_name,
-        const std::vector<UUID> & enabled_roles,
+        const boost::container::flat_set<UUID> & enabled_roles,
         const Poco::Net::IPAddress & address,
         const String & custom_quota_key) const;
 
@@ -76,7 +77,7 @@ public:
 
     std::shared_ptr<const EnabledSettings> getEnabledSettings(const UUID & user_id,
                                                               const SettingsProfileElements & settings_from_user,
-                                                              const std::vector<UUID> & enabled_roles,
+                                                              const boost::container::flat_set<UUID> & enabled_roles,
                                                               const SettingsProfileElements & settings_from_enabled_roles) const;
 
     std::shared_ptr<const SettingsChanges> getProfileSettings(const String & profile_name) const;
diff --git a/src/Access/ContextAccess.cpp b/src/Access/ContextAccess.cpp
index 3a06a9aeead..475a225ba05 100644
--- a/src/Access/ContextAccess.cpp
+++ b/src/Access/ContextAccess.cpp
@@ -121,7 +121,6 @@ void ContextAccess::setUser(const UserPtr & user_) const
         subscription_for_roles_changes = {};
         enabled_roles = nullptr;
         roles_info = nullptr;
-        roles_with_admin_option = nullptr;
         enabled_row_policies = nullptr;
         enabled_quota = nullptr;
         enabled_settings = nullptr;
@@ -131,29 +130,28 @@ void ContextAccess::setUser(const UserPtr & user_) const
     user_name = user->getName();
     trace_log = &Poco::Logger::get("ContextAccess (" + user_name + ")");
 
-    std::vector<UUID> current_roles, current_roles_with_admin_option;
+    boost::container::flat_set<UUID> current_roles, current_roles_with_admin_option;
     if (params.use_default_roles)
     {
         for (const UUID & id : user->granted_roles.roles)
         {
             if (user->default_roles.match(id))
-                current_roles.push_back(id);
+                current_roles.emplace(id);
         }
-        boost::range::set_intersection(current_roles, user->granted_roles.roles_with_admin_option,
-                                       std::back_inserter(current_roles_with_admin_option));
     }
     else
     {
-        current_roles.reserve(params.current_roles.size());
-        for (const auto & id : params.current_roles)
-        {
-            if (user->granted_roles.roles.contains(id))
-                current_roles.push_back(id);
-            if (user->granted_roles.roles_with_admin_option.contains(id))
-                current_roles_with_admin_option.push_back(id);
-        }
+        boost::range::set_intersection(
+            params.current_roles,
+            user->granted_roles.roles,
+            std::inserter(current_roles, current_roles.end()));
     }
 
+    boost::range::set_intersection(
+        current_roles,
+        user->granted_roles.roles_with_admin_option,
+        std::inserter(current_roles_with_admin_option, current_roles_with_admin_option.end()));
+
     subscription_for_roles_changes = {};
     enabled_roles = manager->getEnabledRoles(current_roles, current_roles_with_admin_option);
     subscription_for_roles_changes = enabled_roles->subscribeForChanges([this](const std::shared_ptr<const EnabledRolesInfo> & roles_info_)
@@ -170,7 +168,6 @@ void ContextAccess::setRolesInfo(const std::shared_ptr<const EnabledRolesInfo> &
 {
     assert(roles_info_);
     roles_info = roles_info_;
-    roles_with_admin_option.store(boost::make_shared<boost::container::flat_set<UUID>>(roles_info->enabled_roles_with_admin_option.begin(), roles_info->enabled_roles_with_admin_option.end()));
     boost::range::fill(result_access, nullptr /* need recalculate */);
     enabled_row_policies = manager->getEnabledRowPolicies(*params.user_id, roles_info->enabled_roles);
     enabled_quota = manager->getEnabledQuota(*params.user_id, user_name, roles_info->enabled_roles, params.address, params.quota_key);
@@ -357,10 +354,13 @@ void ContextAccess::checkAdminOption(const UUID & role_id) const
     if (isGranted(AccessType::ROLE_ADMIN))
         return;
 
-    auto roles_with_admin_option_loaded = roles_with_admin_option.load();
-    if (roles_with_admin_option_loaded && roles_with_admin_option_loaded->count(role_id))
+    auto info = getRolesInfo();
+    if (info && info->enabled_roles_with_admin_option.count(role_id))
         return;
 
+    if (!user)
+        throw Exception(user_name + ": User has been dropped", ErrorCodes::UNKNOWN_USER);
+
     std::optional<String> role_name = manager->readName(role_id);
     if (!role_name)
         role_name = "ID {" + toString(role_id) + "}";
@@ -485,30 +485,6 @@ std::shared_ptr<const EnabledRolesInfo> ContextAccess::getRolesInfo() const
     return roles_info;
 }
 
-std::vector<UUID> ContextAccess::getCurrentRoles() const
-{
-    std::lock_guard lock{mutex};
-    return roles_info ? roles_info->current_roles : std::vector<UUID>{};
-}
-
-Strings ContextAccess::getCurrentRolesNames() const
-{
-    std::lock_guard lock{mutex};
-    return roles_info ? roles_info->getCurrentRolesNames() : Strings{};
-}
-
-std::vector<UUID> ContextAccess::getEnabledRoles() const
-{
-    std::lock_guard lock{mutex};
-    return roles_info ? roles_info->enabled_roles : std::vector<UUID>{};
-}
-
-Strings ContextAccess::getEnabledRolesNames() const
-{
-    std::lock_guard lock{mutex};
-    return roles_info ? roles_info->getEnabledRolesNames() : Strings{};
-}
-
 std::shared_ptr<const EnabledRowPolicies> ContextAccess::getRowPolicies() const
 {
     std::lock_guard lock{mutex};
diff --git a/src/Access/ContextAccess.h b/src/Access/ContextAccess.h
index e0fbf58dbe8..9a9f0e31470 100644
--- a/src/Access/ContextAccess.h
+++ b/src/Access/ContextAccess.h
@@ -35,7 +35,7 @@ public:
     struct Params
     {
         std::optional<UUID> user_id;
-        std::vector<UUID> current_roles;
+        boost::container::flat_set<UUID> current_roles;
         bool use_default_roles = false;
         UInt64 readonly = 0;
         bool allow_ddl = false;
@@ -56,22 +56,36 @@ public:
     };
 
     const Params & getParams() const { return params; }
+
+    /// Returns the current user. The function can return nullptr.
     UserPtr getUser() const;
     String getUserName() const;
 
     bool isCorrectPassword(const String & password) const;
     bool isClientHostAllowed() const;
 
+    /// Returns information about current and enabled roles.
+    /// The function can return nullptr.
     std::shared_ptr<const EnabledRolesInfo> getRolesInfo() const;
-    std::vector<UUID> getCurrentRoles() const;
-    Strings getCurrentRolesNames() const;
-    std::vector<UUID> getEnabledRoles() const;
-    Strings getEnabledRolesNames() const;
 
+    /// Returns information about enabled row policies.
+    /// The function can return nullptr.
     std::shared_ptr<const EnabledRowPolicies> getRowPolicies() const;
+
+    /// Returns the row policy filter for a specified table.
+    /// The function returns nullptr if there is no filter to apply.
     ASTPtr getRowPolicyCondition(const String & database, const String & table_name, RowPolicy::ConditionType index, const ASTPtr & extra_condition = nullptr) const;
+
+    /// Returns the quota to track resource consumption.
+    /// The function returns nullptr if no tracking or limitation is needed.
     std::shared_ptr<const EnabledQuota> getQuota() const;
+
+    /// Returns the default settings, i.e. the settings to apply on user's login.
+    /// The function returns nullptr if it's no need to apply settings.
     std::shared_ptr<const Settings> getDefaultSettings() const;
+
+    /// Returns the settings' constraints.
+    /// The function returns nullptr if there are no constraints.
     std::shared_ptr<const SettingsConstraints> getSettingsConstraints() const;
 
     /// Checks if a specified access is granted, and throws an exception if not.
@@ -118,7 +132,8 @@ public:
     /// Checks if a specified role is granted with admin option, and throws an exception if not.
     void checkAdminOption(const UUID & role_id) const;
 
-    /// Returns an instance of ContextAccess which has full access to everything.
+    /// Makes an instance of ContextAccess which provides full access to everything
+    /// without any limitations. This is used for the global context.
     static std::shared_ptr<const ContextAccess> getFullAccess();
 
 private:
@@ -157,7 +172,6 @@ private:
     mutable std::shared_ptr<const EnabledRoles> enabled_roles;
     mutable ext::scope_guard subscription_for_roles_changes;
     mutable std::shared_ptr<const EnabledRolesInfo> roles_info;
-    mutable boost::atomic_shared_ptr<const boost::container::flat_set<UUID>> roles_with_admin_option;
     mutable boost::atomic_shared_ptr<const AccessRights> result_access[7];
     mutable std::shared_ptr<const EnabledRowPolicies> enabled_row_policies;
     mutable std::shared_ptr<const EnabledQuota> enabled_quota;
diff --git a/src/Access/EnabledQuota.h b/src/Access/EnabledQuota.h
index 5a624c651af..e0a04b02206 100644
--- a/src/Access/EnabledQuota.h
+++ b/src/Access/EnabledQuota.h
@@ -23,7 +23,7 @@ public:
     {
         UUID user_id;
         String user_name;
-        std::vector<UUID> enabled_roles;
+        boost::container::flat_set<UUID> enabled_roles;
         Poco::Net::IPAddress client_address;
         String client_key;
 
diff --git a/src/Access/EnabledRoles.h b/src/Access/EnabledRoles.h
index 122b1a16fe3..0c5b799a30b 100644
--- a/src/Access/EnabledRoles.h
+++ b/src/Access/EnabledRoles.h
@@ -2,6 +2,7 @@
 
 #include <Core/UUID.h>
 #include <ext/scope_guard.h>
+#include <boost/container/flat_set.hpp>
 #include <list>
 #include <mutex>
 #include <vector>
@@ -16,8 +17,8 @@ class EnabledRoles
 public:
     struct Params
     {
-        std::vector<UUID> current_roles;
-        std::vector<UUID> current_roles_with_admin_option;
+        boost::container::flat_set<UUID> current_roles;
+        boost::container::flat_set<UUID> current_roles_with_admin_option;
 
         auto toTuple() const { return std::tie(current_roles, current_roles_with_admin_option); }
         friend bool operator ==(const Params & lhs, const Params & rhs) { return lhs.toTuple() == rhs.toTuple(); }
diff --git a/src/Access/EnabledRolesInfo.h b/src/Access/EnabledRolesInfo.h
index 837d4b74ad5..45e1bfd9057 100644
--- a/src/Access/EnabledRolesInfo.h
+++ b/src/Access/EnabledRolesInfo.h
@@ -3,8 +3,8 @@
 #include <Access/AccessRights.h>
 #include <Access/SettingsProfileElement.h>
 #include <Core/UUID.h>
+#include <boost/container/flat_set.hpp>
 #include <unordered_map>
-#include <vector>
 
 
 namespace DB
@@ -13,9 +13,9 @@ namespace DB
 /// Information about a role.
 struct EnabledRolesInfo
 {
-    std::vector<UUID> current_roles;
-    std::vector<UUID> enabled_roles;
-    std::vector<UUID> enabled_roles_with_admin_option;
+    boost::container::flat_set<UUID> current_roles;
+    boost::container::flat_set<UUID> enabled_roles;
+    boost::container::flat_set<UUID> enabled_roles_with_admin_option;
     std::unordered_map<UUID, String> names_of_roles;
     AccessRights access;
     AccessRights access_with_grant_option;
diff --git a/src/Access/EnabledRowPolicies.h b/src/Access/EnabledRowPolicies.h
index 9befb65ff0b..6274850363c 100644
--- a/src/Access/EnabledRowPolicies.h
+++ b/src/Access/EnabledRowPolicies.h
@@ -21,7 +21,7 @@ public:
     struct Params
     {
         UUID user_id;
-        std::vector<UUID> enabled_roles;
+        boost::container::flat_set<UUID> enabled_roles;
 
         auto toTuple() const { return std::tie(user_id, enabled_roles); }
         friend bool operator ==(const Params & lhs, const Params & rhs) { return lhs.toTuple() == rhs.toTuple(); }
diff --git a/src/Access/EnabledSettings.h b/src/Access/EnabledSettings.h
index d8e969d685d..8e92298328c 100644
--- a/src/Access/EnabledSettings.h
+++ b/src/Access/EnabledSettings.h
@@ -5,6 +5,7 @@
 #include <Common/SettingsChanges.h>
 #include <Access/SettingsConstraints.h>
 #include <Access/SettingsProfileElement.h>
+#include <boost/container/flat_set.hpp>
 #include <mutex>
 
 
@@ -17,7 +18,7 @@ public:
     struct Params
     {
         UUID user_id;
-        std::vector<UUID> enabled_roles;
+        boost::container::flat_set<UUID> enabled_roles;
         SettingsProfileElements settings_from_enabled_roles;
         SettingsProfileElements settings_from_user;
 
diff --git a/src/Access/ExtendedRoleSet.cpp b/src/Access/ExtendedRoleSet.cpp
index adee5fea669..a29ee40380c 100644
--- a/src/Access/ExtendedRoleSet.cpp
+++ b/src/Access/ExtendedRoleSet.cpp
@@ -136,26 +136,6 @@ std::shared_ptr<ASTExtendedRoleSet> ExtendedRoleSet::toAST() const
 }
 
 
-String ExtendedRoleSet::toString() const
-{
-    auto ast = toAST();
-    return serializeAST(*ast);
-}
-
-
-Strings ExtendedRoleSet::toStrings() const
-{
-    if (all || !except_ids.empty())
-        return {toString()};
-
-    Strings names;
-    names.reserve(ids.size());
-    for (const UUID & id : ids)
-        names.emplace_back(::DB::toString(id));
-    return names;
-}
-
-
 std::shared_ptr<ASTExtendedRoleSet> ExtendedRoleSet::toASTWithNames(const AccessControlManager & manager) const
 {
     auto ast = std::make_shared<ASTExtendedRoleSet>();
@@ -189,6 +169,13 @@ std::shared_ptr<ASTExtendedRoleSet> ExtendedRoleSet::toASTWithNames(const Access
 }
 
 
+String ExtendedRoleSet::toString() const
+{
+    auto ast = toAST();
+    return serializeAST(*ast);
+}
+
+
 String ExtendedRoleSet::toStringWithNames(const AccessControlManager & manager) const
 {
     auto ast = toASTWithNames(manager);
@@ -198,19 +185,39 @@ String ExtendedRoleSet::toStringWithNames(const AccessControlManager & manager)
 
 Strings ExtendedRoleSet::toStringsWithNames(const AccessControlManager & manager) const
 {
-    if (all || !except_ids.empty())
-        return {toStringWithNames(manager)};
+    if (!all && ids.empty())
+        return {};
 
-    Strings names;
-    names.reserve(ids.size());
-    for (const UUID & id : ids)
+    Strings res;
+    res.reserve(ids.size() + except_ids.size());
+
+    if (all)
+        res.emplace_back("ALL");
+    else
     {
-        auto name = manager.tryReadName(id);
-        if (name)
-            names.emplace_back(std::move(*name));
+        for (const UUID & id : ids)
+        {
+            auto name = manager.tryReadName(id);
+            if (name)
+                res.emplace_back(std::move(*name));
+        }
+        std::sort(res.begin(), res.end());
     }
-    boost::range::sort(names);
-    return names;
+
+    if (!except_ids.empty())
+    {
+        res.emplace_back("EXCEPT");
+        size_t old_size = res.size();
+        for (const UUID & id : except_ids)
+        {
+            auto name = manager.tryReadName(id);
+            if (name)
+                res.emplace_back(std::move(*name));
+        }
+        std::sort(res.begin() + old_size, res.end());
+    }
+
+    return res;
 }
 
 
@@ -247,25 +254,6 @@ bool ExtendedRoleSet::match(const UUID & id) const
 }
 
 
-bool ExtendedRoleSet::match(const UUID & user_id, const std::vector<UUID> & enabled_roles) const
-{
-    if (!all && !ids.count(user_id))
-    {
-        bool found_enabled_role = std::any_of(
-            enabled_roles.begin(), enabled_roles.end(), [this](const UUID & enabled_role) { return ids.count(enabled_role); });
-        if (!found_enabled_role)
-            return false;
-    }
-
-    if (except_ids.count(user_id))
-        return false;
-
-    bool in_except_list = std::any_of(
-        enabled_roles.begin(), enabled_roles.end(), [this](const UUID & enabled_role) { return except_ids.count(enabled_role); });
-    return !in_except_list;
-}
-
-
 bool ExtendedRoleSet::match(const UUID & user_id, const boost::container::flat_set<UUID> & enabled_roles) const
 {
     if (!all && !ids.count(user_id))
diff --git a/src/Access/ExtendedRoleSet.h b/src/Access/ExtendedRoleSet.h
index ba84ade49f8..eeb4af84f78 100644
--- a/src/Access/ExtendedRoleSet.h
+++ b/src/Access/ExtendedRoleSet.h
@@ -36,10 +36,9 @@ struct ExtendedRoleSet
     ExtendedRoleSet(const ASTExtendedRoleSet & ast, const AccessControlManager & manager, const std::optional<UUID> & current_user_id);
 
     std::shared_ptr<ASTExtendedRoleSet> toAST() const;
-    String toString() const;
-    Strings toStrings() const;
-
     std::shared_ptr<ASTExtendedRoleSet> toASTWithNames(const AccessControlManager & manager) const;
+
+    String toString() const;
     String toStringWithNames(const AccessControlManager & manager) const;
     Strings toStringsWithNames(const AccessControlManager & manager) const;
 
@@ -50,7 +49,6 @@ struct ExtendedRoleSet
 
     /// Checks if a specified ID matches this ExtendedRoleSet.
     bool match(const UUID & id) const;
-    bool match(const UUID & user_id, const std::vector<UUID> & enabled_roles) const;
     bool match(const UUID & user_id, const boost::container::flat_set<UUID> & enabled_roles) const;
 
     /// Returns a list of matching IDs. The function must not be called if `all` == `true`.
diff --git a/src/Access/QuotaCache.cpp b/src/Access/QuotaCache.cpp
index dca844bf746..2939d2d1ef2 100644
--- a/src/Access/QuotaCache.cpp
+++ b/src/Access/QuotaCache.cpp
@@ -167,12 +167,7 @@ QuotaCache::QuotaCache(const AccessControlManager & access_control_manager_)
 QuotaCache::~QuotaCache() = default;
 
 
-std::shared_ptr<const EnabledQuota> QuotaCache::getEnabledQuota(
-    const UUID & user_id,
-    const String & user_name,
-    const std::vector<UUID> & enabled_roles,
-    const Poco::Net::IPAddress & client_address,
-    const String & client_key)
+std::shared_ptr<const EnabledQuota> QuotaCache::getEnabledQuota(const UUID & user_id, const String & user_name, const boost::container::flat_set<UUID> & enabled_roles, const Poco::Net::IPAddress & client_address, const String & client_key)
 {
     std::lock_guard lock{mutex};
     ensureAllQuotasRead();
diff --git a/src/Access/QuotaCache.h b/src/Access/QuotaCache.h
index 8399c5f73eb..b9996ed8456 100644
--- a/src/Access/QuotaCache.h
+++ b/src/Access/QuotaCache.h
@@ -20,13 +20,7 @@ public:
     QuotaCache(const AccessControlManager & access_control_manager_);
     ~QuotaCache();
 
-    std::shared_ptr<const EnabledQuota> getEnabledQuota(
-        const UUID & user_id,
-        const String & user_name,
-        const std::vector<UUID> & enabled_roles,
-        const Poco::Net::IPAddress & address,
-        const String & client_key);
-
+    std::shared_ptr<const EnabledQuota> getEnabledQuota(const UUID & user_id, const String & user_name, const boost::container::flat_set<UUID> & enabled_roles, const Poco::Net::IPAddress & address, const String & client_key);
     std::vector<QuotaUsageInfo> getUsageInfo() const;
 
 private:
diff --git a/src/Access/RoleCache.cpp b/src/Access/RoleCache.cpp
index 441e3844a07..ca8065145f3 100644
--- a/src/Access/RoleCache.cpp
+++ b/src/Access/RoleCache.cpp
@@ -2,68 +2,56 @@
 #include <Access/Role.h>
 #include <Access/EnabledRolesInfo.h>
 #include <Access/AccessControlManager.h>
-#include <boost/container/flat_map.hpp>
+#include <boost/container/flat_set.hpp>
 
 
 namespace DB
 {
 namespace
 {
-    struct CollectedRoleInfo
-    {
-        RolePtr role;
-        bool is_current_role = false;
-        bool with_admin_option = false;
-    };
-
-
-    void collectRoles(boost::container::flat_map<UUID, CollectedRoleInfo> & collected_roles,
+    void collectRoles(EnabledRolesInfo & roles_info,
+                      boost::container::flat_set<UUID> & skip_ids,
                       const std::function<RolePtr(const UUID &)> & get_role_function,
                       const UUID & role_id,
                       bool is_current_role,
                       bool with_admin_option)
     {
-        auto it = collected_roles.find(role_id);
-        if (it != collected_roles.end())
+        if (roles_info.enabled_roles.count(role_id))
         {
-            it->second.is_current_role |= is_current_role;
-            it->second.with_admin_option |= with_admin_option;
+            if (is_current_role)
+                roles_info.current_roles.emplace(role_id);
+            if (with_admin_option)
+                roles_info.enabled_roles_with_admin_option.emplace(role_id);
             return;
         }
 
+        if (skip_ids.count(role_id))
+            return;
+
         auto role = get_role_function(role_id);
-        collected_roles[role_id] = CollectedRoleInfo{role, is_current_role, with_admin_option};
 
         if (!role)
+        {
+            skip_ids.emplace(role_id);
             return;
+        }
+
+        roles_info.enabled_roles.emplace(role_id);
+        if (is_current_role)
+            roles_info.current_roles.emplace(role_id);
+        if (with_admin_option)
+            roles_info.enabled_roles_with_admin_option.emplace(role_id);
+
+        roles_info.names_of_roles[role_id] = role->getName();
+        roles_info.access.merge(role->access.access);
+        roles_info.access_with_grant_option.merge(role->access.access_with_grant_option);
+        roles_info.settings_from_enabled_roles.merge(role->settings);
 
         for (const auto & granted_role : role->granted_roles.roles)
-            collectRoles(collected_roles, get_role_function, granted_role, false, false);
+            collectRoles(roles_info, skip_ids, get_role_function, granted_role, false, false);
 
         for (const auto & granted_role : role->granted_roles.roles_with_admin_option)
-            collectRoles(collected_roles, get_role_function, granted_role, false, true);
-    }
-
-
-    std::shared_ptr<EnabledRolesInfo> collectInfoForRoles(const boost::container::flat_map<UUID, CollectedRoleInfo> & roles)
-    {
-        auto new_info = std::make_shared<EnabledRolesInfo>();
-        for (const auto & [role_id, collect_info] : roles)
-        {
-            const auto & role = collect_info.role;
-            if (!role)
-                continue;
-            if (collect_info.is_current_role)
-                new_info->current_roles.emplace_back(role_id);
-            new_info->enabled_roles.emplace_back(role_id);
-            if (collect_info.with_admin_option)
-                new_info->enabled_roles_with_admin_option.emplace_back(role_id);
-            new_info->names_of_roles[role_id] = role->getName();
-            new_info->access.merge(role->access.access);
-            new_info->access_with_grant_option.merge(role->access.access_with_grant_option);
-            new_info->settings_from_enabled_roles.merge(role->settings);
-        }
-        return new_info;
+            collectRoles(roles_info, skip_ids, get_role_function, granted_role, false, true);
     }
 }
 
@@ -75,8 +63,8 @@ RoleCache::RoleCache(const AccessControlManager & manager_)
 RoleCache::~RoleCache() = default;
 
 
-std::shared_ptr<const EnabledRoles> RoleCache::getEnabledRoles(
-    const std::vector<UUID> & roles, const std::vector<UUID> & roles_with_admin_option)
+std::shared_ptr<const EnabledRoles>
+RoleCache::getEnabledRoles(const boost::container::flat_set<UUID> & roles, const boost::container::flat_set<UUID> & roles_with_admin_option)
 {
     std::lock_guard lock{mutex};
 
@@ -93,13 +81,13 @@ std::shared_ptr<const EnabledRoles> RoleCache::getEnabledRoles(
     }
 
     auto res = std::shared_ptr<EnabledRoles>(new EnabledRoles(params));
-    collectRolesInfoFor(*res);
+    collectEnabledRoles(*res);
     enabled_roles.emplace(std::move(params), res);
     return res;
 }
 
 
-void RoleCache::collectRolesInfo()
+void RoleCache::collectEnabledRoles()
 {
     /// `mutex` is already locked.
 
@@ -110,28 +98,29 @@ void RoleCache::collectRolesInfo()
             i = enabled_roles.erase(i);
         else
         {
-            collectRolesInfoFor(*elem);
+            collectEnabledRoles(*elem);
             ++i;
         }
     }
 }
 
 
-void RoleCache::collectRolesInfoFor(EnabledRoles & enabled)
+void RoleCache::collectEnabledRoles(EnabledRoles & enabled)
 {
     /// `mutex` is already locked.
 
-    /// Collect roles in use. That includes the current roles, the roles granted to the current roles, and so on.
-    boost::container::flat_map<UUID, CollectedRoleInfo> collected_roles;
+    /// Collect enabled roles. That includes the current roles, the roles granted to the current roles, and so on.
+    auto new_info = std::make_shared<EnabledRolesInfo>();
+    boost::container::flat_set<UUID> skip_ids;
     auto get_role_function = [this](const UUID & id) { return getRole(id); };
     for (const auto & current_role : enabled.params.current_roles)
-        collectRoles(collected_roles, get_role_function, current_role, true, false);
+        collectRoles(*new_info, skip_ids, get_role_function, current_role, true, false);
 
     for (const auto & current_role : enabled.params.current_roles_with_admin_option)
-        collectRoles(collected_roles, get_role_function, current_role, true, true);
+        collectRoles(*new_info, skip_ids, get_role_function, current_role, true, true);
 
     /// Collect data from the collected roles.
-    enabled.setRolesInfo(collectInfoForRoles(collected_roles));
+    enabled.setRolesInfo(new_info);
 }
 
 
@@ -174,7 +163,7 @@ void RoleCache::roleChanged(const UUID & role_id, const RolePtr & changed_role)
         return;
     role_from_cache->first = changed_role;
     cache.update(role_id, role_from_cache);
-    collectRolesInfo();
+    collectEnabledRoles();
 }
 
 
@@ -182,7 +171,7 @@ void RoleCache::roleRemoved(const UUID & role_id)
 {
     std::lock_guard lock{mutex};
     cache.remove(role_id);
-    collectRolesInfo();
+    collectEnabledRoles();
 }
 
 }
diff --git a/src/Access/RoleCache.h b/src/Access/RoleCache.h
index 69f4cb2ebe8..f1ef783b5c4 100644
--- a/src/Access/RoleCache.h
+++ b/src/Access/RoleCache.h
@@ -2,6 +2,7 @@
 
 #include <Access/EnabledRoles.h>
 #include <Poco/ExpireCache.h>
+#include <boost/container/flat_set.hpp>
 #include <map>
 #include <mutex>
 
@@ -18,11 +19,12 @@ public:
     RoleCache(const AccessControlManager & manager_);
     ~RoleCache();
 
-    std::shared_ptr<const EnabledRoles> getEnabledRoles(const std::vector<UUID> & current_roles, const std::vector<UUID> & current_roles_with_admin_option);
+    std::shared_ptr<const EnabledRoles> getEnabledRoles(
+        const boost::container::flat_set<UUID> & current_roles, const boost::container::flat_set<UUID> & current_roles_with_admin_option);
 
 private:
-    void collectRolesInfo();
-    void collectRolesInfoFor(EnabledRoles & enabled);
+    void collectEnabledRoles();
+    void collectEnabledRoles(EnabledRoles & enabled);
     RolePtr getRole(const UUID & role_id);
     void roleChanged(const UUID & role_id, const RolePtr & changed_role);
     void roleRemoved(const UUID & role_id);
diff --git a/src/Access/RowPolicyCache.cpp b/src/Access/RowPolicyCache.cpp
index 0c9fea69dc4..06ccf021dad 100644
--- a/src/Access/RowPolicyCache.cpp
+++ b/src/Access/RowPolicyCache.cpp
@@ -99,7 +99,7 @@ RowPolicyCache::RowPolicyCache(const AccessControlManager & access_control_manag
 RowPolicyCache::~RowPolicyCache() = default;
 
 
-std::shared_ptr<const EnabledRowPolicies> RowPolicyCache::getEnabledRowPolicies(const UUID & user_id, const std::vector<UUID> & enabled_roles)
+std::shared_ptr<const EnabledRowPolicies> RowPolicyCache::getEnabledRowPolicies(const UUID & user_id, const boost::container::flat_set<UUID> & enabled_roles)
 {
     std::lock_guard lock{mutex};
     ensureAllRowPoliciesRead();
diff --git a/src/Access/RowPolicyCache.h b/src/Access/RowPolicyCache.h
index d0ec74b9ab8..3b4ecd6e8f5 100644
--- a/src/Access/RowPolicyCache.h
+++ b/src/Access/RowPolicyCache.h
@@ -18,7 +18,7 @@ public:
     RowPolicyCache(const AccessControlManager & access_control_manager_);
     ~RowPolicyCache();
 
-    std::shared_ptr<const EnabledRowPolicies> getEnabledRowPolicies(const UUID & user_id, const std::vector<UUID> & enabled_roles);
+    std::shared_ptr<const EnabledRowPolicies> getEnabledRowPolicies(const UUID & user_id, const boost::container::flat_set<UUID> & enabled_roles);
 
 private:
     using ParsedConditions = EnabledRowPolicies::ParsedConditions;
diff --git a/src/Access/SettingsProfilesCache.cpp b/src/Access/SettingsProfilesCache.cpp
index 516b47213fe..3f9399ca484 100644
--- a/src/Access/SettingsProfilesCache.cpp
+++ b/src/Access/SettingsProfilesCache.cpp
@@ -183,7 +183,7 @@ void SettingsProfilesCache::substituteProfiles(SettingsProfileElements & element
 std::shared_ptr<const EnabledSettings> SettingsProfilesCache::getEnabledSettings(
     const UUID & user_id,
     const SettingsProfileElements & settings_from_user,
-    const std::vector<UUID> & enabled_roles,
+    const boost::container::flat_set<UUID> & enabled_roles,
     const SettingsProfileElements & settings_from_enabled_roles)
 {
     std::lock_guard lock{mutex};
diff --git a/src/Access/SettingsProfilesCache.h b/src/Access/SettingsProfilesCache.h
index 656ffc6fce6..42dd05df351 100644
--- a/src/Access/SettingsProfilesCache.h
+++ b/src/Access/SettingsProfilesCache.h
@@ -29,7 +29,7 @@ public:
     std::shared_ptr<const EnabledSettings> getEnabledSettings(
         const UUID & user_id,
         const SettingsProfileElements & settings_from_user_,
-        const std::vector<UUID> & enabled_roles,
+        const boost::container::flat_set<UUID> & enabled_roles,
         const SettingsProfileElements & settings_from_enabled_roles_);
 
     std::shared_ptr<const SettingsChanges> getProfileSettings(const String & profile_name);
diff --git a/src/Interpreters/Context.cpp b/src/Interpreters/Context.cpp
index f5651a1ab77..d6176c50ba4 100644
--- a/src/Interpreters/Context.cpp
+++ b/src/Interpreters/Context.cpp
@@ -28,6 +28,7 @@
 #include <Core/Settings.h>
 #include <Access/AccessControlManager.h>
 #include <Access/ContextAccess.h>
+#include <Access/EnabledRolesInfo.h>
 #include <Access/EnabledRowPolicies.h>
 #include <Access/User.h>
 #include <Access/SettingsProfile.h>
@@ -698,7 +699,7 @@ std::optional<UUID> Context::getUserID() const
 }
 
 
-void Context::setCurrentRoles(const std::vector<UUID> & current_roles_)
+void Context::setCurrentRoles(const boost::container::flat_set<UUID> & current_roles_)
 {
     auto lock = getLock();
     if (current_roles == current_roles_ && !use_default_roles)
@@ -718,24 +719,19 @@ void Context::setCurrentRolesDefault()
     calculateAccessRights();
 }
 
-std::vector<UUID> Context::getCurrentRoles() const
+boost::container::flat_set<UUID> Context::getCurrentRoles() const
 {
-    return getAccess()->getCurrentRoles();
+    return getRolesInfo()->current_roles;
 }
 
-Strings Context::getCurrentRolesNames() const
+boost::container::flat_set<UUID> Context::getEnabledRoles() const
 {
-    return getAccess()->getCurrentRolesNames();
+    return getRolesInfo()->enabled_roles;
 }
 
-std::vector<UUID> Context::getEnabledRoles() const
+std::shared_ptr<const EnabledRolesInfo> Context::getRolesInfo() const
 {
-    return getAccess()->getEnabledRoles();
-}
-
-Strings Context::getEnabledRolesNames() const
-{
-    return getAccess()->getEnabledRolesNames();
+    return getAccess()->getRolesInfo();
 }
 
 
diff --git a/src/Interpreters/Context.h b/src/Interpreters/Context.h
index 0d2b3cdb5af..6cb2893af98 100644
--- a/src/Interpreters/Context.h
+++ b/src/Interpreters/Context.h
@@ -51,6 +51,7 @@ class Context;
 class ContextAccess;
 struct User;
 using UserPtr = std::shared_ptr<const User>;
+struct EnabledRolesInfo;
 class EnabledRowPolicies;
 class EnabledQuota;
 class AccessFlags;
@@ -166,7 +167,7 @@ private:
     InputBlocksReader input_blocks_reader;
 
     std::optional<UUID> user_id;
-    std::vector<UUID> current_roles;
+    boost::container::flat_set<UUID> current_roles;
     bool use_default_roles = false;
     std::shared_ptr<const ContextAccess> access;
     std::shared_ptr<const EnabledRowPolicies> initial_row_policy;
@@ -254,12 +255,11 @@ public:
     String getUserName() const;
     std::optional<UUID> getUserID() const;
 
-    void setCurrentRoles(const std::vector<UUID> & current_roles_);
+    void setCurrentRoles(const boost::container::flat_set<UUID> & current_roles_);
     void setCurrentRolesDefault();
-    std::vector<UUID> getCurrentRoles() const;
-    Strings getCurrentRolesNames() const;
-    std::vector<UUID> getEnabledRoles() const;
-    Strings getEnabledRolesNames() const;
+    boost::container::flat_set<UUID> getCurrentRoles() const;
+    boost::container::flat_set<UUID> getEnabledRoles() const;
+    std::shared_ptr<const EnabledRolesInfo> getRolesInfo() const;
 
     /// Checks access rights.
     /// Empty database means the current database.
diff --git a/src/Interpreters/InterpreterSetRoleQuery.cpp b/src/Interpreters/InterpreterSetRoleQuery.cpp
index f56926332ec..f8e0167d748 100644
--- a/src/Interpreters/InterpreterSetRoleQuery.cpp
+++ b/src/Interpreters/InterpreterSetRoleQuery.cpp
@@ -39,20 +39,20 @@ void InterpreterSetRoleQuery::setRole(const ASTSetRoleQuery & query)
     else
     {
         ExtendedRoleSet roles_from_query{*query.roles, access_control};
-        std::vector<UUID> new_current_roles;
+        boost::container::flat_set<UUID> new_current_roles;
         if (roles_from_query.all)
         {
             for (const auto & id : user->granted_roles.roles)
                 if (roles_from_query.match(id))
-                    new_current_roles.push_back(id);
+                    new_current_roles.emplace(id);
         }
         else
         {
             for (const auto & id : roles_from_query.getMatchingIDs())
             {
-                if (!user->granted_roles.roles.contains(id))
+                if (!user->granted_roles.roles.count(id))
                     throw Exception("Role should be granted to set current", ErrorCodes::SET_NON_GRANTED_ROLE);
-                new_current_roles.push_back(id);
+                new_current_roles.emplace(id);
             }
         }
         session_context.setCurrentRoles(new_current_roles);
@@ -85,7 +85,7 @@ void InterpreterSetRoleQuery::updateUserSetDefaultRoles(User & user, const Exten
     {
         for (const auto & id : roles_from_query.getMatchingIDs())
         {
-            if (!user.granted_roles.roles.contains(id))
+            if (!user.granted_roles.roles.count(id))
                 throw Exception("Role should be granted to set default", ErrorCodes::SET_NON_GRANTED_ROLE);
         }
     }