Speeding up Database Access with mod_perl
Now that we have our test program, how can we actually test it? I wrote a short Perl program using Benchmark.pm, in Listing 3. The timethese function is imported by Benchmark.pm, which we bring in at the beginning of the program. We also bring in LWP::Simple, part of the “Library for WWW access in Perl” that makes it a snap to write a small web client. How simple? Well, the following one-liner returns the HTML contents at http://www.linuxjournal.com/:
perl -e 'use LWP::Simple; print get "http://www.linuxjournal.com";'
Perl does not format the output for you. That's the difference between a web browser and a web client; the former is meant to retrieve information for humans, while the latter is meant to retrieve information for programs. In this particular case, we just want to simulate 100 retrievals of each of our programs via the web. Any timing differences will thus be due to the program on the server side—which, since they are identical, means that the differences will be due to mod_perl and Apache::DBI.
How much faster is the Apache::DBI version than its CGI counterpart? Here are the results I got running time-db.pl:
 ~% ./time-db.pl Benchmark: timing 100 iterations ... Apache::DBI: 24 secs (1.77 usr 0.67 sys = 2.44 cpu) Plain CGI: 394 secs (1.10 usr 0.61 sys = 1.71 cpu)
That's quite a difference. When I first ran this benchmark, I was convinced that the plain CGI program had somehow gotten stuck. Alas, that was not the case; the overhead associated with CGI was simply too great.
Here is a second run of the same benchmark, just for comparison.
 ~% ./time-db.pl Benchmark: timing 100 iterations ... Apache::DBI: 28 secs (1.89 usr 0.61 sys = 2.50 cpu) Plain CGI: 355 secs (1.15 usr 0.62 sys = 1.77 cpu)
Yes, it looks like CGI is indeed much slower. By the way, you can see that Apache::DBI used more CPU time than plain CGI—which means that the time was spent forking the new Perl process, rather than performing our program's computations.
What if we take out the Apache::DBI directive in srm.conf and restart the server? That would give us an indication of how much overhead was being used opening the database connection. As you can see, things do indeed slow down—although admittedly not by a huge amount:
 ~% ./time-db.pl Benchmark: timing 100 iterations ... Apache::DBI: 34 secs (1.97 usr 0.63 sys = 2.60 cpu) Plain CGI: 460 secs (1.19 usr 0.60 sys = 1.79 cpu)
The moral, then, seems to be that moving from CGI to mod_perl gives a huge performance boost, and that moving from DBI to Apache::DBI gives a moderate performance boost. The more database accesses your web applications do, the more useful these technologies will probably be in your work. Perl has always been known as a useful language, but rarely as one that can help you write fast software. Now, with mod_perl and Apache::DBI, you can write web applications quickly, and watch them run quickly as well.
Fast/Flexible Linux OS Recovery
On Demand Now
In this live one-hour webinar, learn how to enhance your existing backup strategies for complete disaster recovery preparedness using Storix System Backup Administrator (SBAdmin), a highly flexible full-system recovery solution for UNIX and Linux systems.
Join Linux Journal's Shawn Powers and David Huffman, President/CEO, Storix, Inc.
Free to Linux Journal readers.Register Now!
- Server Hardening
- BitTorrent Inc.'s Sync
- Download "Linux Management with Red Hat Satellite: Measuring Business Impact and ROI"
- New Container Image Standard Promises More Portable Apps
- The Humble Hacker?
- The Death of RoboVM
- The US Government and Open-Source Software
- Open-Source Project Secretly Funded by CIA
- EnterpriseDB's EDB Postgres Advanced Server and EDB Postgres Enterprise Manager
- ACI Worldwide's UP Retail Payments
In modern computer systems, privacy and security are mandatory. However, connections from the outside over public networks automatically imply risks. One easily available solution to avoid eavesdroppers’ attempts is SSH. But, its wide adoption during the past 21 years has made it a target for attackers, so hardening your system properly is a must.
Additionally, in highly regulated markets, you must comply with specific operational requirements, proving that you conform to standards and even that you have included new mandatory authentication methods, such as two-factor authentication. In this ebook, I discuss SSH and how to configure and manage it to guarantee that your network is safe, your data is secure and that you comply with relevant regulations.Get the Guide