Yejun, Thanks for the updated code example. Since a counter is such a common need, I think it might be helpful if we all worked together on the same codebase, rather than forking each time, or at least if we could be specific about the changes we made (I know I can do a diff, but if you noted what exactly you changed, and why, that would be awesome for all future users who are curious).
Moving on, I think I didn't explain myself well regarding the destruction of the memcache object. Imagine an app where 1) There will definitely be at least 10 counter requests/sec (for same named counter. let's call it the TotalRequests counter, and is referred to by some Stats model) 2) Lots and lots of other entities get written to memcache (millions of entities in the system, and each gets cached upon initial request) In this situation, it is guaranteed objects in our memcache will disappear after some use, since we have less memcache total avail than the size of items that will be cached over a few days of use. Now, which items get removed? In this case, our counter is the first created item in memcache, and definitely one of the first items to be just nuked from memcache when we hit the max storage limit for our apps' memcache. To ensure it never gets nuked due to it being the 'oldest object in memcache', then we could 'occasionally' destroy/ recreate it. Maybe, for example, I could also have a time_created on it, and if it's older than a few hours, then nuke/recreate upon resetting it. I figured might as well do this every time, but anyway hopefully you see my point as to why I was thinking about the need to destroy/reuse. Much more important than this very occasional mis-count for a destroyed memcache item, tho, is my general idea of just not even attempting to write to a shard entity unless we've had a few (10?, 50?) counter increments. I am getting ~350ms/request average due to the time it takes writing to the shards (multiple counters/request), and this is my main concern with the current code. I will diff your code (thanks again) and check it out this afternoon. -Josh On Nov 3, 12:22 pm, yejun <[EMAIL PROTECTED]> wrote: > > To solve this, I'm also > > planning to destroy and recreate the memcache object upon successful > > datastore write (and associated memcache delay being reset to zero). > > You shouldn't do this. It the completely negates the reason why you > use this counter class. > If you just need a counter for a local object, you should just save > the counter with object itself. > > This counter class should only be used in situation when the same > named counter need to be increment more than 10 times per second by > different requests/users concurrently. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
