MySQL vs PostgreSQL: The Architect's Dilemma in the Wake of the Oracle Acquisition

It has been a turbulent year for the open-source community. With Oracle closing its acquisition of Sun Microsystems back in January, many of us managing VPS Norway infrastructure are looking at our LAMP stacks with a degree of nervousness. Is MySQL still the safe bet? Or does the release of PostgreSQL 9.0 last month signal a changing of the guard?

I have spent the last decade debugging my.cnf files across Scandinavian data centers, from chilly server rooms in Tromsø to enterprise racks in Oslo. If there is one thing I have learned, it is that database choice is rarely about syntax—it is about concurrency, data integrity, and how much sleep you want to get on weekends.

Let's cut through the FUD (Fear, Uncertainty, and Doubt) and look at the technical reality of choosing a database engine for your next project on CoolVDS.

The MySQL Proposition: Speed at a Price

MySQL is still the undisputed king of the web. It is the 'M' in LAMP for a reason. If you are running Drupal, Joomla, or WordPress, you are likely defaulting to MySQL 5.1. Its ubiquity is its strength.

However, the default storage engine, MyISAM, is a relic we need to stop using for writes. MyISAM uses table-level locking. This means if a user writes a comment on your blog, the entire table locks up. On a high-traffic site, this creates a queue of processes waiting for the lock to release, driving your load average through the roof.

The Fix: InnoDB

If you stick with MySQL, you must migrate to InnoDB. It supports row-level locking and transactions (ACID compliance). Here is the configuration you need to check in /etc/my.cnf immediately to ensure you aren't bottlenecking on disk I/O:

[mysqld]
# Use InnoDB as default
default-storage-engine = InnoDB

# The most critical setting. Set this to 70-80% of your VPS RAM.
# On a 4GB CoolVDS instance, set this to 3G.
innodb_buffer_pool_size = 3G

# Log file size should be about 25% of the buffer pool
innodb_log_file_size = 256M

# Avoid double buffering by the OS
innodb_flush_method = O_DIRECT

PostgreSQL 9.0: The New Challenger

For years, SysAdmins avoided PostgreSQL because replication was a nightmare. We had to use complex trigger-based solutions like Slony-I. That changed last month with the release of PostgreSQL 9.0. It introduced built-in Hot Standby and Streaming Replication.

This is a massive shift. You can now have a read-only replica serving complex reporting queries while your master handles the writes. For data-critical applications—think banking or patient records governed by the Personal Data Act (Personopplysningsloven)—PostgreSQL's strict adherence to SQL standards and data types makes it superior.

Pro Tip: PostgreSQL handles concurrency differently using MVCC (Multi-Version Concurrency Control). Readers don't block writers, and writers don't block readers. This is ideal for complex applications with heavy mixed workloads.

Performance Tuning Postgres

Out of the box, Postgres is configured for compatibility, not speed. On a dedicated CoolVDS slice, you need to tell the kernel to allow more shared memory. You often need to tweak /etc/sysctl.conf first:

# /etc/sysctl.conf
# Increase max shared memory to 2GB (value in bytes)
kernel.shmmax = 2147483648
kernel.shmall = 524288

Run sysctl -p to apply, then edit postgresql.conf:

# /var/lib/pgsql/data/postgresql.conf

# Set to 25% of total RAM
shared_buffers = 1GB

# Set to effective amount of RAM available for disk caching
effective_cache_size = 3GB

# Checkpoints: increasing this reduces I/O spikes but increases recovery time
checkpoint_segments = 32

A Tale of Two Latencies: A Real-World Scenario

Last month, I migrated a Norwegian e-commerce client from a generic US host to our infrastructure. They were running a Magento store on MySQL with MyISAM tables. During a marketing campaign, their database locked up completely. Customers were seeing "Connection Timed Out" errors.

The solution wasn't just code; it was architecture. We moved them to a CoolVDS instance with RAID-10 SAS storage (essential for database random I/O) and migrated the schema to InnoDB. The result? The lock wait time dropped from seconds to milliseconds.

The Hardware Factor: Why CoolVDS?

Software optimization can only take you so far. Databases are I/O bound. If your host is putting you on a crowded server with standard SATA drives, no amount of caching will save you when the disk heads are thrashing.

At CoolVDS, we don't oversell our backend. We use enterprise-grade storage arrays with battery-backed write caches. This ensures that when your database issues a fsync, the data is actually safe, without stalling the CPU waiting for the platter to spin. For Norwegian businesses concerned with Datatilsynet audits, knowing your data integrity is backed by redundant hardware is not optional—it's a requirement.

Security and Latency

Keeping your database close to your users is critical. If your customers are in Oslo or Bergen, hosting in Germany or Norway offers significantly lower latency than the US East Coast. A 150ms round-trip time to the US adds up when your application makes 50 sequential database queries per page load.

Furthermore, under the EU Data Protection Directive, keeping data within the EEA simplifies your legal compliance significantly compared to relying on the US Safe Harbor framework, which is increasingly under scrutiny by privacy advocates.

Conclusion: Make the Call

If you need raw read speed for a simple CMS, MySQL 5.1 with InnoDB is still a valid workhorse. But if you are building a complex application requiring complex queries, strict data integrity, or master-slave replication for high availability, PostgreSQL 9.0 is the superior engineering choice.

Whichever engine you choose, it needs a stable home. Don't let slow I/O kill your query performance.

Ready to benchmark your database? Deploy a high-performance Linux instance on CoolVDS today and see the difference dedicated resources make.