Added option to ini files for controlling full cache of VCS instances.

This can increase performance for huge repositories like 300K changesets

development.ini

@@ -60,6 +60,7 b' cache_dir = %(here)s/data'
 index_dir = %(here)s/data/index
 app_instance_uuid = rc-develop
 cut_off_limit = 256000
+vcs_full_cache = True
 force_https = false
 commit_parse_limit = 25
 use_gravatar = true

production.ini

@@ -60,6 +60,7 b' cache_dir = %(here)s/data'
 index_dir = %(here)s/data/index
 app_instance_uuid = rc-production
 cut_off_limit = 256000
+vcs_full_cache = True
 force_https = false
 commit_parse_limit = 50
 use_gravatar = true

rhodecode/config/deployment.ini_tmpl

@@ -60,6 +60,7 b' cache_dir = %(here)s/data'
 index_dir = %(here)s/data/index
 app_instance_uuid = ${app_instance_uuid}
 cut_off_limit = 256000
+vcs_full_cache = True
 force_https = false
 commit_parse_limit = 50
 use_gravatar = true

rhodecode/model/db.py

@@ -941,7 +941,10 b' class Repository(Base, BaseModel):'
 
     @LazyProperty
     def scm_instance(self):
-        return self.scm_instance_cached()
+        import rhodecode
+        full_cache = str2bool(rhodecode.CONFIG.get('vcs_full_cache'))
+        if full_cache:
+            return self.scm_instance_cached()
         return self.__get_instance()
 
     def scm_instance_cached(self, cache_map=None):