On Fri, 17 Sep 2004 10:45:18 -0400
Perrin Harkins <[EMAIL PROTECTED]> wrote:
Hi Perrin,
> Enrico Sorcinelli wrote:
> > I'm glad to announce Apache::Session::Memcached.
> > This module provides a way to use memcached as Apache::Session storage
> > implementation
>
> I wouldn't recommend using memcached for storing sessions. Memcached is
> explicitly unreliable storage. It is built with the premise that you
> won't put anything into it that you care about losing.
> If it gets full,
> it will simply drop data from storage. The mechanism for failover
> across multiple machines also counts on being able to lose all the data
> from one machine without it being a big deal.
Yes, I know. Probably, a RDBMS as session datastore is currently best (and
economical) solution for multiple frontends. Another solution is a load-balancer
with sticky sessions.
I'm investigating in order to search fastest datastore, so, I wrote also A::S::M
since I worked with memcached in the past and I there was not a Apache::Session
implementation (moreover, this has been a good exercise in order to better
hacking in deep Apache::Session :-))
I've done some basic benchmarks using Apache::Session::Flex with different
datastores and memcached is very fast when sessions number grows (see below).
> Memcached would be better suited to acting as a write-through cache for
> session data that you store in a database.
Please, can you better explain?
Tnx, for comments! ;-)
by
- Enrico
---
my Apache::Session(::Flex) benchmark results
***
*** 10 ***
***
----------------
Store: File, Times: 50
----------------
the code took: 0 wallclock secs ( 0.05 usr + 0.01 sys = 0.06 CPU)
----------------
Store: Memcached, Times: 50
----------------
the code took: 0 wallclock secs ( 0.15 usr + 0.00 sys = 0.15 CPU)
----------------
Store: MySQL, Times: 50
----------------
the code took: 1 wallclock secs ( 0.18 usr + 0.03 sys = 0.21 CPU)
----------------
Store: DB_File, Times: 50
----------------
the code took: 0 wallclock secs ( 0.07 usr + 0.01 sys = 0.08 CPU)
----------------
Store: SharedMem, Times: 50
----------------
the code took: 0 wallclock secs ( 0.11 usr + 0.00 sys = 0.11 CPU)
***
*** 100 ***
***
----------------
Store: File, Times: 100
----------------
the code took: 0 wallclock secs ( 0.09 usr + 0.02 sys = 0.11 CPU)
----------------
Store: Memcached, Times: 100
----------------
the code took: 1 wallclock secs ( 0.14 usr + 0.04 sys = 0.18 CPU)
----------------
Store: MySQL, Times: 100
----------------
the code took: 0 wallclock secs ( 0.38 usr + 0.00 sys = 0.38 CPU)
----------------
Store: DB_File, Times: 100
----------------
the code took: 1 wallclock secs ( 0.22 usr + 0.02 sys = 0.24 CPU)
----------------
Store: SharedMem, Times: 100
----------------
the code took: 0 wallclock secs ( 0.32 usr + 0.00 sys = 0.32 CPU)
***
*** 1000 ***
***
----------------
Store: File, Times: 1000
----------------
the code took: 1 wallclock secs ( 0.79 usr + 0.21 sys = 1.00 CPU)
----------------
Store: Memcached, Times: 1000
----------------
the code took: 2 wallclock secs ( 1.21 usr + 0.08 sys = 1.29 CPU)
----------------
Store: MySQL, Times: 1000
----------------
the code took: 5 wallclock secs ( 2.98 usr + 0.17 sys = 3.15 CPU)
----------------
Store: DB_File, Times: 1000
----------------
the code took: 3 wallclock secs ( 1.73 usr + 0.29 sys = 2.02 CPU)
----------------
Store: SharedMem, Times: 1000
----------------
the code took:19 wallclock secs (18.11 usr + 0.94 sys = 19.05 CPU)
***
*** 10000 ***
***
----------------
Store: File, Times: 10000
----------------
the code took:21 wallclock secs ( 9.33 usr + 11.12 sys = 20.45 CPU)
----------------
Store: Memcached, Times: 10000
----------------
the code took:20 wallclock secs (12.45 usr + 1.09 sys = 13.54 CPU)
----------------
Store: MySQL, Times: 10000
----------------
the code took:41 wallclock secs (29.34 usr + 1.25 sys = 30.59 CPU)
----------------
Store: DB_File, Times: 10000
----------------
the code took:33 wallclock secs (14.90 usr + 1.89 sys = 16.79 CPU)
----------------
Store: SharedMem, Times: 10000
----------------
the code took:2657 wallclock secs (2450.79 usr + 196.40 sys = 2647.19 CPU)
--
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