PostgreSQL vs. MySQL: The Battle for Your Data

It has been six months since Oracle closed the deal to acquire Sun Microsystems, and let’s be honest: the sysadmin community is nervous. For years, the LAMP stack (Linux, Apache, MySQL, PHP) has been the default standard for everything from WordPress blogs to massive eCommerce platforms. But with the uncertain future of MySQL under a proprietary giant, and the rise of PostgreSQL 8.4 as a serious performance contender, the "default choice" isn't so simple anymore.

I recently spent 48 hours debugging a corrupted MyISAM table for a client in Oslo. The server lost power, the table didn't lock correctly, and data vanished. That doesn't happen if you choose your tools based on engineering constraints rather than popularity.

The MySQL Proposition: Speed vs. Safety

MySQL is everywhere. It is the engine of the web. Version 5.1 is stable, and if you are running read-heavy workloads (like a news site or a forum), it is blazing fast. However, many developers still default to the MyISAM storage engine because it's the default configuration on most distributions (RHEL, Debian, CentOS).

The Trap: MyISAM uses table-level locking. If one user is writing to a table, nobody else can read from it until the write is done. On a high-traffic site, this creates a queue that spikes your load average instantly.

If you stick with MySQL, you simply must use InnoDB. It provides row-level locking and transaction support (ACID). But tuning it requires touching the my.cnf file. Most standard VPS providers give you a default config that assumes you have 64MB of RAM. It's a joke.

# Inside /etc/my.cnf
# The most critical setting for InnoDB performance
innodb_buffer_pool_size = 1G  # Set this to 70-80% of available RAM on a dedicated DB server
innodb_flush_log_at_trx_commit = 1 # Essential for ACID compliance, though it hits I/O hard

The PostgreSQL Alternative: The "Strict" Parent

If MySQL is the fast sports car that might crash if you take a corner too hard, PostgreSQL is the tank. With version 8.4 released last year, we finally got reasonable performance improvements to go with its legendary reliability. It strictly adheres to SQL standards.

Why use Postgres? Data Integrity.

PostgreSQL won't let you insert a string into an integer field silently. It supports complex queries, sub-selects, and the new Window Functions in 8.4 are a lifesaver for analytics. If you are handling financial data or sensitive user records subject to the Norwegian Personal Data Act (Personopplysningsloven), you want the database that refuses to corrupt data, even if the kernel panics.

The I/O Bottleneck

Here is the reality check: It doesn't matter if you choose MySQL or Postgres if your underlying storage is trash. Databases are I/O bound. They live and die by how fast they can write to the disk.

In a standard shared hosting environment, or a cheap VPS using OpenVZ, you are fighting for disk access with hundreds of other noisy neighbors. If someone else is compiling a kernel, your database queries hang. This is why we argue for KVM virtualization. It provides better isolation.

Pro Tip: Check your disk latency. If you are seeing high %iowait in top, your CPU isn't the problem—your disk is. We are beginning to see Solid State Drives (SSDs) enter the enterprise market. While expensive, placing your transaction logs on an SSD volume can increase throughput by 10x compared to standard 15k RPM SAS drives.

Comparing the Engines

The CoolVDS Advantage: Hardware Matters

Software tuning only gets you so far. At CoolVDS, we don't oversell our nodes. We understand that a database server in Norway needs to serve requests to Oslo in under 10 milliseconds.

We use high-performance RAID 10 SAS arrays and are currently rolling out Enterprise SSD tiering for heavy database workloads. Combined with KVM virtualization, this ensures that your innodb_buffer_pool stays in RAM and your disk writes don't get queued behind a noisy neighbor.

Plus, keeping your data in our Oslo data center ensures you are fully compliant with Datatilsynet regulations regarding data sovereignty—something US-based clouds like EC2 can make legally complicated.

Final Verdict

Use MySQL if you are running a standard CMS like Joomla or Drupal and need raw read speed. Use PostgreSQL if you are building a custom application where data integrity is paramount.

Whichever you choose, don't run it on a slow disk. Deploy a high-performance KVM VPS with CoolVDS today and see what proper I/O isolation does for your query times.