Re: Why is memcache.Get so much slower than datastore_v3.Get

[Bryce Cutt]

Other than the one outlier at the top of your image your numbers look pretty typical to me.

Memcache can have a very variable response time. I have seen them go as high as 1 second on a bad day but this has been rare. On a usual day I see average times around 5ms to 20ms with occasional spikes to 200ms. The numbers are always very application specific as well; I can have two applications doing the exact same memcache requests and one will be twice as fast as the other all the time (due to noisy neighbors or different data centers or whatever).

I get the impression from other posts that those numbers are not abnormal. I believe Brandon Wirtz posted a ton of numbers at some point based on his extensive experience optimizing for speed on GAE.

Here are the latency averages GAE is reporting today:

http://code.google.com/status/appengine/detail/memcache/2012/08/24

- Bryce

On Friday, August 24, 2012 8:52:22 AM UTC-7, Mobicage wrote:

Hi

I experience that getting things (successfully) from memcache is much slower than getting them from the datastore:
see the following appstat report:
http://oi49.tinypic.com/2yvrnlz.jpg

My memcache keys are rather long e.g.
'v1.Z2V0X3Byb2ZpbGUuY29tLm1vYmljYWdlLmRhbC5wcm9maWxlMTExEQAAAGNhcmxAbW9iaWNhZ2UuY29t'

What could be the reason for such behaviour?