- trashed_check = if !include_trash then
- "AND trashed = 0"
- else
- ""
- end
-
- owner_check = if sql_table != "api_client_authorizations" and sql_table != "groups" then
- "OR (target_uuid = #{sql_table}.owner_uuid AND target_owner_uuid IS NOT NULL)"
- else
- ""
- end
-
- sql_conds.push "EXISTS(SELECT 1 FROM #{PERMISSION_VIEW} "+
- "WHERE user_uuid IN (:user_uuids) AND perm_level >= 1 #{trashed_check} AND (target_uuid = #{sql_table}.uuid #{owner_check})) "+
- exclude_trashed_records
+ trashed_check = ""
+ if !include_trash then
+ trashed_check = "AND trashed = 0"
+ end
+
+ # Note: it is possible to combine the direct_check and
+ # owner_check into a single EXISTS() clause, however it turns
+ # out query optimizer doesn't like it and forces a sequential
+ # table scan. Constructing the query with separate EXISTS()
+ # clauses enables it to use the index.
+ #
+ # see issue 13208 for details.
+
+ # Match a direct read permission link from the user to the record uuid
+ direct_check = "EXISTS(SELECT 1 FROM #{PERMISSION_VIEW} "+
+ "WHERE user_uuid IN (:user_uuids) AND perm_level >= 1 #{trashed_check} AND target_uuid = #{sql_table}.uuid)"
+
+ # Match a read permission link from the user to the record's owner_uuid
+ owner_check = ""
+ if sql_table != "api_client_authorizations" and sql_table != "groups" then
+ owner_check = "OR EXISTS(SELECT 1 FROM #{PERMISSION_VIEW} "+
+ "WHERE user_uuid IN (:user_uuids) AND perm_level >= 1 #{trashed_check} AND target_uuid = #{sql_table}.owner_uuid AND target_owner_uuid IS NOT NULL) "
+ end