kallithea Changeset - efce61aac33d

Changeset - efce61aac33d

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stable

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Mads Kiilerich - 10 years ago 2015-12-25 12:37:49
madski@unity3d.com

db: handle race when multiple threads add the same cache invalidation entry simultaneously (Issue #177)

1 file changed with 7 insertions and 1 deletions:

kallithea/model/db.py

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kallithea/model/db.py

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@@ @@ -2133,25 +2133,31 @@ class CacheInvalidation(Base, BaseModel) @@
         cache_key = cls._get_cache_key(key)
         if valid_cache_keys and cache_key in valid_cache_keys:
             return True
         inv_obj = cls.query().filter(cls.cache_key == cache_key).scalar()
         if not inv_obj:
             inv_obj = CacheInvalidation(cache_key, repo_name)
         if inv_obj.cache_active:
             return True
         inv_obj.cache_active = True
         Session().add(inv_obj)
         Session().commit()
         try:
             Session().commit()
         except exc.IntegrityError:
             inv_obj = cls.query().filter(cls.cache_key == cache_key).scalar()
             if not inv_obj:
                 raise
             # TOCTOU - another thread added the key at the same time; no further action required
         return False
     @classmethod
     def get_valid_cache_keys(cls):
         """
         Return opaque object with information of which caches still are valid
         and can be used without checking for invalidation.
         """
         return set(inv_obj.cache_key for inv_obj in cls.query().filter(cls.cache_active).all())
 class ChangesetComment(Base, BaseModel):

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