Comments on: APC or Memcached http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/ Everything about MySQL Performance Sat, 21 Nov 2009 05:23:57 -0800 http://wordpress.org/?v=2.8.4 hourly 1 By: Anirudh Zala http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/comment-page-1/#comment-645228 Anirudh Zala Wed, 02 Sep 2009 08:03:32 +0000 http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/#comment-645228 I have not much experience to both of these technologies. But I have an interesting question about performance of APC and Memcache. Consider a scenario where "An application that is running on 4 webservers behind load balancer (which divides requests according to load on each server)". Each web server has 4gb of RAM. Now what would be better solution for implementing caching strategy on above servers? 1: Assigning 100MB to APC on each webserver OR 2: Using a separate Mamcached enabled machine with 4gb of RAM. I have not much experience to both of these technologies. But I have an interesting question about performance of APC and Memcache. Consider a scenario where “An application that is running on 4 webservers behind load balancer (which divides requests according to load on each server)”. Each web server has 4gb of RAM.

Now what would be better solution for implementing caching strategy on above servers?

1: Assigning 100MB to APC on each webserver OR
2: Using a separate Mamcached enabled machine with 4gb of RAM.

]]> By: » links for 2009-03-20 Thej Live http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/comment-page-1/#comment-514102 » links for 2009-03-20 Thej Live Sat, 21 Mar 2009 05:01:25 +0000 http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/#comment-514102 [...] APC or Memcached | MySQL Performance Blog APC Cache (Eaccelerator and other similar caches) is Fast but it is not distributed so you’re wasting cache and reducing possible hit rate by caching things locally if you have many web servers. MemcacheD is relatively slow but distributed and so you do not waste memory by caching same item in a few places, it is also faster to warmup as you need only one access to bring item into the cache, not access for each of web servers. (tags: apc cache php) [...] [...] APC or Memcached | MySQL Performance Blog APC Cache (Eaccelerator and other similar caches) is Fast but it is not distributed so you’re wasting cache and reducing possible hit rate by caching things locally if you have many web servers. MemcacheD is relatively slow but distributed and so you do not waste memory by caching same item in a few places, it is also faster to warmup as you need only one access to bring item into the cache, not access for each of web servers. (tags: apc cache php) [...]

]]> By: PHP Memory Caching Performance | AF-Design http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/comment-page-1/#comment-458867 PHP Memory Caching Performance | AF-Design Thu, 29 Jan 2009 05:22:32 +0000 http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/#comment-458867 [...] with both APC and Memcached in a production environment. I’ve read that the performance of APC is roughly 3-5x faster than Memcache. So I decided to do my own test to see which performed better on my rig. If you want [...] [...] with both APC and Memcached in a production environment. I’ve read that the performance of APC is roughly 3-5x faster than Memcache. So I decided to do my own test to see which performed better on my rig. If you want [...]

]]> By: Johnny http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/comment-page-1/#comment-315424 Johnny Fri, 20 Jun 2008 13:00:55 +0000 http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/#comment-315424 I just laugh when I read this, I developed my own framework focused on advanced cache control methods and functionality. I use both APC and Memcached combined. I use each where they will be most efficiently effective. One is not really better than the other, they are designed to do different things. If you want to create something amazing, use them in tandem. I just laugh when I read this, I developed my own framework focused on advanced cache control methods and functionality. I use both APC and Memcached combined. I use each where they will be most efficiently effective. One is not really better than the other, they are designed to do different things. If you want to create something amazing, use them in tandem.

]]> By: Stephen Johnston http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/comment-page-1/#comment-298190 Stephen Johnston Tue, 13 May 2008 00:17:42 +0000 http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/#comment-298190 Memecached has a 1 megabyte item limit, so your 50mb objects are out of luck with memcached anyway. Memecached has a 1 megabyte item limit, so your 50mb objects are out of luck with memcached anyway.

]]> By: perlchild http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/comment-page-1/#comment-195186 perlchild Fri, 16 Nov 2007 17:21:14 +0000 http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/#comment-195186 50MB? Some of my developers have larger objects than that... (external xml imports, so no way to shrink them either) 50MB?
Some of my developers have larger objects than that…
(external xml imports, so no way to shrink them either)

]]> By: peter http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/comment-page-1/#comment-179314 peter Sat, 20 Oct 2007 15:41:54 +0000 http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/#comment-179314 Enzo, Even if you have multipe web servers there are some things which you can cache in local APC - yes they will be copied on all of your web nodes but if their total size is say 50MB why would you care ? Cache invalidation is another problem which can be done with TTL and versions even in such envinronment. Enzo,

Even if you have multipe web servers there are some things which you can cache in local APC – yes they will be copied on all of your web nodes but if their total size is say 50MB why would you care ?

Cache invalidation is another problem which can be done with TTL and versions even in such envinronment.

]]> By: Enzo http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/comment-page-1/#comment-179071 Enzo Fri, 19 Oct 2007 20:43:22 +0000 http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/#comment-179071 If you have multiple webservers, then local APC caches aren't going to cut it. Request will be load balanced across various servers and so what was cached on one server will no be in the cache on the other server so you'll end up w/ more cache misses. Memcached solves this problem since it is distributed. If you have multiple webservers, then local APC caches aren’t going to cut it. Request will be load balanced across various servers and so what was cached on one server will no be in the cache on the other server so you’ll end up w/ more cache misses.

Memcached solves this problem since it is distributed.

]]> By: Memcached: When You Absolutely Positively Have to Get It To Scale the Next Day « SmoothSpan Blog http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/comment-page-1/#comment-171288 Memcached: When You Absolutely Positively Have to Get It To Scale the Next Day « SmoothSpan Blog Sun, 23 Sep 2007 21:25:14 +0000 http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/#comment-171288 [...] Memcached is slower than local caches such as APC cache since it is distributed.  However, it has the potential to store a lot more objects since it can harness many machines.  Consider whether your application benefits from a really big cache, or whether some of the objects aren’t better off with smaller, higher performance, local caches. [...] [...] Memcached is slower than local caches such as APC cache since it is distributed.  However, it has the potential to store a lot more objects since it can harness many machines.  Consider whether your application benefits from a really big cache, or whether some of the objects aren’t better off with smaller, higher performance, local caches. [...]

]]> By: peter http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/comment-page-1/#comment-4730 peter Tue, 03 Oct 2006 13:30:26 +0000 http://www.mysqlperformanceblog.com/2006/09/27/apc-or-memcached/#comment-4730 Robin, It might be hard to convince people to use anything. Especially if this is technology which they are not familiar with. In the case you're speaking about I would probably use small local APC cache plus distributed memcached, running on the same set of boxes. Memcached is fast but even run locally it is much slower than APC. For most applications you would not notice too much differnece to be honest as even 20.000 of lookups per second means your pages will be lightning fast even with 100 cache lookups per cache :) Robin,

It might be hard to convince people to use anything. Especially if this is technology which they are not familiar with.

In the case you’re speaking about I would probably use small local APC cache plus distributed memcached, running on the same set of boxes. Memcached is fast but even run locally it is much slower than APC.

For most applications you would not notice too much differnece to be honest as even 20.000 of lookups per second means your pages will be lightning fast even with 100 cache lookups per cache :)

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