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Displaying posts with tag: postgresql (reset)
Same query, 3 databases, 3 different results

The SQL standard leaves a lot of room for different implementations. This is a little demonstration of one of such differences.

SQLite  3.7.4
sqlite> create table t1 (id serial, t time);
sqlite> insert into t1(t) values ('00:05:10');
sqlite> select t,t*1.5 from t1;
00:05:10|0.0
MySQL 5.6.4-m5
mysql> create table t1 (id serial, t time);
Query OK, 0 rows affected (0.01 sec)

mysql> insert into t1(t) values ('00:05:10');
Query OK, 1 row affected (0.00 sec)

mysql> select t,t*1.5 from t1;
+----------+-------+
| t        | t*1.5 |
+----------+-------+
| 00:05:10 |   765 |
+----------+-------+
1 row in set (0.00 sec)

PostgreSQL 9.0.3
test=# create table t1 (id serial, t time);
NOTICE:  CREATE TABLE will create implicit …

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When systems scale better than linearly

I’ve been seeing a few occasions where Neil J. Gunther’s Universal Scalability Law doesn’t seem to model all of the important factors in a system as it scales. Models are only models, and they’re not the whole truth, so they never match reality perfectly. But there appear to be a small number of cases where systems can actually scale a bit better than linearly over a portion of the domain, due to what I’ve been calling an “economy of scale.” I believe that the Universal Scalability Law might need a third factor (seriality, coherency, and the new factor, economy of scale). I don’t think that the results I’m seeing can be modeled adequately with only two parameters.

Here are two publicly available cases that appear to demonstrate this phenomenon: Robert Haas’s recent blog post on PostgreSQL, titled …

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Open Source Hardware

Back in 2010 I stopped buying test servers from Dell and began building them from components using Intel i7 processors, X58-based mother boards, and modular power supplies from Ultra.  It was a good way to learn about hardware.  Besides, it was getting old to pay for Dell desktop systems with Windows, which I would then wipe off when installing Linux.  Between the educational value of understanding the systems better, selecting the exact components I wanted, and being able to fix problems quickly, it has been one of the best investments I have ever made.  And it didn't cost any more than equivalent Dell servers.

For this reason, a couple of recent articles about computer hardware caught my attention.  First, Dell is losing business as companies like Facebook build their own …

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451 CAOS Links 2011.09.23

Red Hat revenue up 28% in Q2. Funding for NoSQL vendors. And more.

# Red Hat reported net income of $40m in the second quarter on revenue up 28% to $281.3m.

# 10gen raised $20m in funding, while DataStax closed an $11m series B round, while also releasing its DataStax Enterprise and Community products. Additionally Neo Technology …

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Blog Summary for Week of September 5

1. Apache and MySQL Logging with Syslog-ng
This article shows how to use the popular system logging tool Syslog-ng to log Apache and MySQL events. Apache does not log via syslog-ng by default so we go over two methods of easily remedying this. We also show how to use SQL queries to view syslog-ng data.

2. Using M3 to take System Monitors to the Next Level
Monitis provides built in functionality to monitor a wide variety of system statistics as well as the ability to create custom system monitors. Monitis Monitor Manager, or M3 for short, allows you to take these custom monitors …

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What's Next for Tungsten Replicator

As Giuseppe Maxia recently posted we released Tungsten Replicator 2.0.4 this week.  It has a raft of bug fixes and new features of which one-line installations are the single biggest improvement.  I set up replicators dozens of times a day and having a single command for standard cluster topologies is a huge step forward.  Kudos to Jeff Mace for getting this nailed down.

So what's next?  You can get see what we are up to in general by looking at our issues list.  We cannot do everything at once, but here are the current priorities for Tungsten Replicator 2.0.5.

  • Parallel replication speed and robustness. …
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451 CAOS Links 2011.08.31

MapR and Funambol raise funding. VMware virtually supports PostgreSQL. And more.

# MapR raised $20m series B for its Hadoop distribution from Redpoint Ventures, Lightspeed Venture Partners and NEA.

# Funambol raised $3m in funding from previous investors HIG Ventures, Pacven Walden Ventures and Nexit Infocom.

# VMware launched vFabric Postgres as part of vFabric Data Director database-as-a-service launch.

# Citrix released a new edition of CloudStack, …

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Mobile Internet Access in Germany for Open Source Road Warriors

Reliable Internet access is a long-standing problem for road warriors visiting foreign countries.  Open source developers in particular have problems reconciling travel with addiction to high-bandwidth network access from laptop computers.  Wi-Fi hotspots are scarce, costly, often slow, and in some cases complicated by inconvenient local laws like Italy's Pisanu Decree.  International mobile network access plans are ridiculously expensive or like DROAM have download limits that make them useless for serious programming.

The best solution in many cases is to look for a local pre-paid mobile access plan in each country you visit.   Mobile networks are widely available and fast in developed regions, and there are cheap plans that limit the amount you pay while …

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I’ll be presenting at Postgres Open 2011

I’ve been accepted to present at the brand-new and very exciting Postgres Open 2011 about system scaling, TCP traffic, and mathematical modeling. I’m really looking forward to it — it will be my first PostgreSQL conference in a couple of years! See you there.

Related posts:

  1. Postgres folks, consider the 2011 MySQL conference
  2. O’Reilly MySQL 2011 conference CfP is open
  3. My sessions at the O’Reilly MySQL Conference 2011
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PostGIS 1.5 in Postgresql 9.0 install on CentOS 5.6

I love short and consist install instructions. I know this is a MySQL blog but our good friend PostGreSQL has a great GIS library. This is what I learned upgrading our PostGIS system to GIS 1.5. Much thanks to Jeremy Tunnell for give this document it’s start.

Start with CentOS 5.6 x86_64 basic install.

Add the PostgreSQL Yum repository to your system.

$ wget http://yum.pgrpms.org/reporpms/9.0/pgdg-centos-9.0-2.noarch.rpm
 $ rpm -i pgdg-centos-9.0-2.noarch.rpm

Another location for these is DAG. I have to tried these so your results may very.

You will need to exclude the packages CentOS provide by added two lines to the BASE and UPDATE sections of /etc/yum.repos.d/CentOS-Base.repo. They are:

exclude=postgresql*
exclude=geos*

You you are ready to install the needed packages. This includes proj version 4 and geos version 3.

 $ yum install postgresql90-contrib.x86_64
 $ yum …
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