Clean up SQL cache when it gets big, break up huge batches of ROA

requests to avoid timeouts.  See #274.

svn path=/trunk/; revision=4607

1 files changed, 14 insertions, 0 deletions

diff --git a/rpkid/rpki/sql.py b/rpkid/rpki/sql.py
index b6be65b6..14d1e1fb 100644
--- a/rpkid/rpki/sql.py
+++ b/rpkid/rpki/sql.py
@@ -41,6 +41,11 @@ class session(object):
   SQL session layer.
   """
 
+  ## @var clear_threshold
+  # Size above which .cache_clear_maybe() should clear the cache.
+
+  clear_threshold = 5000
+
   def __init__(self, cfg):
 
     self.username = cfg.get("sql-username")
@@ -92,8 +97,17 @@ class session(object):
     """
     Clear the object cache.
     """
+    rpki.log.debug("Clearing SQL cache")
+    self.assert_pristine()
     self.cache.clear()
 
+  def cache_clear_maybe(self):
+    """
+    Clear the object cache if its size is above clear_threshold.
+    """
+    if len(self.cache) >= self.clear_threshold:
+      self.cache_clear()
+
   def assert_pristine(self):
     """
     Assert that there are no dirty objects in the cache.