Changes between Version 6 and Version 7 of TracDev/Proposals/CacheInvalidation

Timestamp:

Mar 16, 2009, 7:13:58 PM (15 years ago)

Author:

Christian Boos

Comment:

feedback on prototype implementation of idea 2

TracDev/Proposals/CacheInvalidation

@@ +1 @@
+[[PageOutline(2-4)]]
 = The problem of cache invalidation =
 
@@ -96 +97 @@
  * Two new `trac-admin` commands allow listing the `cache` table and invalidating one or more caches. They are intended for debugging purposes, and should probably be removed if the proposal is applied to trunk.
 
+=== Discussion ===
 '''Comments and testing are very welcome'''. The implementation is quite complete, except for the missing database upgrade module. I have only tested with several concurrent `tracd` instances so far.
 
+==== cboos' feedback ====
+It's really nice, I like it a lot!
+
+When reviewing the code, I think I've detected some possible issues in `CacheManager.get`.
+ - in case there are multiple "out-of-date" threads, each might trigger a retrieval. An improvement would be to check if the `CacheManager` already has a "newer" generation.
+ - in the locked section, if the generation increases after the cached value retrieval and before the fetch of the latest generation, the `CacheManager` may think it is up to date yet have old data.
+Those are admittedly corner cases, I hope I have not missed more important issues while focusing on that ;-) See the first patch attachment:cache-manager_get-corner-cases.patch.
+
+Another little improvement I'd like to propose is to not have to bother with key names and let the decorators figure out the key from the method itself. See attachment:cache-manager-automatic-key.patch. 
+I've also added more documentation to the decorators and changed the order of the definitions in a top-down way (first the decorators, then the descriptors, ending with the proxy class), as I think it's easier to understand that way.
 
 == Idea 2: Cache control ==
@@ -111 +123 @@
 
 
-==== Example: InterMapTxt cache ====
+=== Example: InterMapTxt cache ===
 For convenience, if a Component only manages one cache (the common case), it can pass `self` instead of a string key and its class name will be used.