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Displaying posts with tag: memcache (reset)
When it’s faster to use SQL in MySQL NDB Cluster over memcache API

Memcache access for MySQL Cluster (or NDBCluster) provides faster access to the data because it avoids the SQL parsing overhead for simple lookups – which is a great feature. But what happens if I try to get multiple records via memcache API (multi-GET) and via SQL (SELECT with IN())? I’ve encountered this a few times now, so I decided to blog about it. I did a very simple benchmark with the following script:

#!/bin/bash
mysql_server="192.168.56.75"
mc_server="192.168.56.75"
mysql_cmd="mysql -h${mysql_server} --silent --silent"
mysql_schema="percona"
mysql_table="memcache_t"
mc_port=11211
mc_prefix="mt:"
function populate_data () {
  nrec=$1
  $mysql_cmd -e "delete from ${mysql_table};" $mysql_schema > /dev/null 2>&1
  for rec in `seq 1 $nrec`
  do
    $mysql_cmd -e "insert into ${mysql_table} values ($rec, repeat('a',10), 0, 0);" $mysql_schema > /dev/null 2>&1
  done
}
function mget_via_sql() {
  nrec=$1
  in_list=''
  for rec in …
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1.5x … 9x faster queries with PHP and MySQL 5.6, really?

I am telling no secret saying MySQL 5.6 GA can be expected to be released soon, very soon. Time to test one of the improvements: MySQL 5.6 speaks SQL and Memcache protocol. In your PHP MySQL apps, try using the Memcache protocol to query MySQL. A key-value SELECT ... FROM ... WHERE pk = <key> can become 1.5x-2x faster, an INSERT INTO table(pk, ...) VALUES (<key> ...) can become 4.5x-9x faster, says the InnoDB team! Read on: background, benchmark, usage, PECL/mysqlnd_memcache, …

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Stop Disabling SELinux!

I see a lot of people coming by #centos and similar channels asking for help when they’re experiencing a problem with their Linux system. It amazes me how many people describe their problem, and then say something along the lines of, “and I disabled SELinux...”. Most of the time SELinux has nothing to do with the problem, and if SELinux is the cause of the problem, why would you throw out the extra security by disabling it completely rather than configuring it to work with your application?

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High Performance PHP Session Storage on Scale

One of the great things about the HTTP protocol, besides status code 418, is that it's stateless. A web server therefore is not required to store any information on the user or allocate resources for a user after the individual request is done. By that a single web server can handle many many many different users easily, and well if it can't anymore one can add a new server, put a simple load balancer in front and scale out. Each of those web servers then handles its requests without the need for communication which leads to linear scaling (assuming network provides enough bandwidth etc.).

Now the Web isn't used for serving static documents only anymore but we have all these fancy web apps. And those applications often have the need for a state. The most trivial information they need is the current user. HTTP is a great protocol and provides a way to do authentication which …

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5 Tips to Cache Websites and Boost Speed

Read the original article at 5 Tips to Cache Websites and Boost Speed

Often when we think about speeding up and scaling, we focus on the application layer itself.  We look at the webserver tier, and database tier, and optimize the most resource intensive pages.

There's much more we can do to speed things up, if we only turn over the right stones.  Whether you're using WordPress or not, many of these principals can be applied.  However we'll use WordPress as our test case.

Test Your Website speed

There are web-based speed testing tools that will help with this step.  Take a look at Webpagetest , …

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Not only SQL - memcache and MySQL 5.6

This week there are two big events for the MySQL community: The O'Reilly MySQL Conference and Oracle Collaborate run by the IOUG. At these events our Engineering VP, Tomas Ulin, announced the latest milestone releases for our main products. MySQL 5.6 and MySQL Cluster 7.1 as well as our new Windows Installer. There's lots of cool stuff in there but one feature really excited me: MySQL 5.6 contains a memcache interface for accessing InnoDB tables. This means you can access data stored in MySQL not only using SQL statements but also by using a well established and known noSQL protocol.

This works by having the memcache daemon running as plugin as part of the MySQL server. This daemon can then be configured in three ways: Either

  • to do what memcached always …
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HandlerSocket is great, but don't compare it to Memcache just yet.

The HandlerSocket plugin for MySQL currently lacks atomic operations .  It is impossible to implement counters (increment/decrement value) or REPLACE functionality with the current implementation. 

It currently exceeds the performance of Memcache for get/set operations, but I want to see how fast it is once atomic operations are implemented. Until then, I don't think it is a serious contender for replacing Memcache for the cache layer in a complex environment.

Caching could be the last thing you want to do

I recently had a run-in with a very popular PHP ecommerce package which makes me want to voice a recurring mistake I see in how many web applications are architected.

What is that mistake?

The ecommerce package I was working with depended on caching.  Out of the box it couldn't serve 10 pages/second unless I enabled some features which were designed to be "optional" (but clearly they weren't).

I think with great tools like memcached it is easy to get carried away and use it as the mallet for every performance problem, but in many cases it should not be your first choice.  Here is why:

  • Caching might not work for all visitors - You look at a page, it loads fast.  But is this the same for every user?  Caching can sometimes be an optimization that makes the average user have a faster experience, but in reality you should be caring more that …
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Redis, Memcached, Tokyo Tyrant and MySQL comparision

I wanted to compare the following DBs, NoSQLs and caching solutions for speed and connections. Tested the following

My test had the following criteria

  • 2 client boxes
  • All clients connecting to the server using Python
  • Used Python's threads to create concurrency
  • Each thread made 10,000 open-close connections to the server
  • The server …
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Storage Miniconf Deadline Extended!

The linux.conf.au organisers have given all miniconfs an additional few weeks to spruik for more proposal submissions, huzzah!

So if you didn’t submit a proposal because you weren’t sure whether you’d be able to attend LCA2010, you now have until October 23 to convince your boss to send you and get your proposal in.

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