[Zope-DB] Bug in ZSQL method result caching?

[Chris Withers]

Hi All,

I'm seeing a fair few errors as follows using Zope 2.8.4:

     results = self.aZSQLMethod(p1=value1, p2=value2)
   File "lib/python/Shared/DC/ZRDB/DA.py",line 453, in __call__
     result=self._cached_result(DB__, (query, self.max_rows_))
   File "lib/python/Shared/DC/ZRDB/DA.py",line 375, in _cached_result
     if int(cache[q][0]) == key:
KeyError: ("execute dbo.aStoredProcedure 'VALUE1', 'VALUE2'\n",
            1000,
            '\nDBConnId: None')

The code in question is this, from DA.py:

         # Try to fetch from cache
         if hasattr(self,'_v_cache'): cache=self._v_cache
         else: cache=self._v_cache={}, Bucket()
         cache, tcache = cache
         max_cache=self.max_cache_
         now=time()
         t=now-self.cache_time_
         if len(cache) > max_cache / 2:
             keys=tcache.keys()
             keys.reverse()
             while keys and (len(keys) > max_cache or keys[-1] < t):
                 key=keys[-1]
                 q=tcache[key]
                 del tcache[key]
                 if int(cache[q][0]) == key:
                     del cache[q]
                 del keys[-1]


The if clause seems a bit dodgy...

Is that while loop maybe iterating over a mutable object while deleting 
stuff from it?

I'm only stabbing in the dark here...

Does anyone have any better ideas?

cheers,

Chris

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