Improve naming of group caches

Throughout Gerrit, the members of a group always refer to accounts.
For some reason, the cache for the subgroups of a group also used the
term 'members'. To reduce confusion (especially with the newly
introduced cache for the groups which contain a specific account), we
change the name of the caches relating to subgroups.

Change-Id: I8e1e4e91045f9f4769c75e7c48e57a019ac97069

Documentation/cmd-show-caches.txt

@@ -61,12 +61,12 @@ Intended for interactive use only.
     adv_bases                     |                     |         |         |
     changes                       |                     |  27.1ms |  0%     |
     groups                        |  5646               |  11.8ms | 97%     |
-    groups_byinclude              |   230               |   2.4ms | 62%     |
     groups_bymember               |                     |         |         |
     groups_byname                 |                     |         |         |
+    groups_bysubgroup             |   230               |   2.4ms | 62%     |
     groups_byuuid                 |  5612               |  29.2ms | 99%     |
     groups_external               |     1               |   1.5s  | 98%     |
-    groups_members                |  5714               |  19.7ms | 99%     |
+    groups_subgroups              |  5714               |  19.7ms | 99%     |
     ldap_group_existence          |                     |         |         |
     ldap_groups                   |   650               | 680.5ms | 99%     |
     ldap_groups_byinclude         |  1024               |         | 83%     |

Documentation/config-gerrit.txt

@@ -847,18 +847,18 @@ including the group owner, name, and description.
 External group membership obtained from LDAP is cached under
 `"ldap_groups"`.
 
-cache `"groups_byinclude"`::
-+
-Caches group inclusions in other groups.  If direct updates are made
-to the `account_group_includes` table, this cache should be flushed.
-
 cache `"groups_bymember"`::
 +
 Caches the groups which contain a specific member (account). If direct
 updates are made to the `account_group_members` table, this cache should
 be flushed.
 
-cache `"groups_members"`::
+cache `"groups_bysubgroups"`::
++
+Caches the parent groups of a subgroup.  If direct updates are made
+to the `account_group_includes` table, this cache should be flushed.
+
+cache `"groups_subgroups"`::
 +
 Caches subgroups.  If direct updates are made to the
 `account_group_includes` table, this cache should be flushed.

Documentation/rest-api-config.txt

@@ -333,11 +333,6 @@ The entries in the map are sorted by cache name.
         "mem": 12
       }
     },
-    "groups_byinclude": {
-      "type": "MEM",
-      "entries": {},
-      "hit_ratio": {}
-    },
     "groups_bymember": {
       "type": "MEM",
       "entries": {},
@@ -348,6 +343,11 @@ The entries in the map are sorted by cache name.
       "entries": {},
       "hit_ratio": {}
     },
+    "groups_bysubgroup": {
+      "type": "MEM",
+      "entries": {},
+      "hit_ratio": {}
+    },
     "groups_byuuid": {
       "type": "MEM",
       "entries": {
@@ -363,7 +363,7 @@ The entries in the map are sorted by cache name.
       "entries": {},
       "hit_ratio": {}
     },
-    groups_members": {
+    groups_subgroups": {
       "type": "MEM",
       "entries": {
         "mem": 4
@@ -472,12 +472,12 @@ The cache names are lexicographically sorted.
     "diff_intraline",
     "git_tags",
     "groups",
-    "groups_byinclude",
     "groups_bymember",
     "groups_byname",
+    "groups_bysubgroup",
     "groups_byuuid",
     "groups_external",
-    "groups_members",
+    "groups_subgroups",
     "permission_sort",
     "plugin_resources",
     "project_list",

gerrit-server/src/main/java/com/google/gerrit/server/account/GroupIncludeCache.java

@@ -29,10 +29,20 @@ public interface GroupIncludeCache {
    */
   Collection<AccountGroup.UUID> getGroupsWithMember(Account.Id memberId);
 
-  /** @return groups directly a member of the passed group. */
+  /**
+   * Returns the subgroups of a group.
+   *
+   * @param group the UUID of the group
+   * @return the UUIDs of all direct subgroups
+   */
   Collection<AccountGroup.UUID> subgroupsOf(AccountGroup.UUID group);
 
-  /** @return any groups the passed group belongs to. */
+  /**
+   * Returns the parent groups of a subgroup.
+   *
+   * @param groupId the UUID of the subgroup
+   * @return the UUIDs of all direct parent groups
+   */
   Collection<AccountGroup.UUID> parentGroupsOf(AccountGroup.UUID groupId);
 
   /** @return set of any UUIDs that are not internal groups. */

gerrit-server/src/main/java/com/google/gerrit/server/account/GroupIncludeCacheImpl.java

@@ -52,8 +52,8 @@ import org.slf4j.LoggerFactory;
 @Singleton
 public class GroupIncludeCacheImpl implements GroupIncludeCache {
   private static final Logger log = LoggerFactory.getLogger(GroupIncludeCacheImpl.class);
-  private static final String PARENT_GROUPS_NAME = "groups_byinclude";
-  private static final String SUBGROUPS_NAME = "groups_members";
+  private static final String PARENT_GROUPS_NAME = "groups_bysubgroup";
+  private static final String SUBGROUPS_NAME = "groups_subgroups";
   private static final String GROUPS_WITH_MEMBER_NAME = "groups_bymember";
   private static final String EXTERNAL_NAME = "groups_external";