Deprecated - Performance and scalability

I've searched for quite a while now with no luck.

I'm looking for any sort of tool that will search for key words or phrases throughout the site. When it finds those words or phrases, it should automatically turn them into links referenced in the database that connects them.

Example:
On April 30, 1789, George Washington, standing on the balcony of Federal Hall on Wall Street in New York, took his oath of office as the first President of the United States.

My database sort of went berserk day (it was a problem with the sessions table, emptying that table seems to have taken care of everything for the moment) and while I was in phpmyadmin trying to clean up the mess I noticed to my chagrin that the watchdog table in mysql was taking up ONE THIRD of the entire database size.

Keep in mind that my site is a webcomic with ten years worth of comic archives.

So I went ahead and cleared that table, and all is dandy... but I was wondering if any of you had any good ideas as to how to handle Watchdog? Most of the time the information is useless to me because the majority of the information it reports is that some site is trying to retrieve graphic files that aren't there. There are a number of sites that download/mirror my comics, and the automation they've set up isn't particularly good -- they're constantly looking for comics that haven't been posted yet. While the most convenient solution (for me) would be for those sites to either improve their image-grabbing bots or stop using them all together, I don't have any control over that.

Hi everyone,
According to devel module , my page load time (on local server) is about 650ms (30ms is for queries) and i have APC installed. it's very high i think!!.
What is your page load time , is it natural in druapl? or my system is so slow!

CPU : AMD Athlon X2 3800
RAM : 1 GIG
OS : Windows XP SP2
Server : XAMPP (Apache2, PHP5)

I read over several php performance blogs that for performance issues it is batter to call $_SERVER['REQUEST_TIME'] instead of time() to get the current unix timestamp. But ( at least in Drupal 5.7) look what i get:
# grep -R 'time()' . | wc -l
# 104
This is with my custom modules added, so probably the result is with an error of +5 calls to time().
Anyway, i think there must be a real reason why we don't get the timestamp from $_SERVER['REQUEST_TIME'], but i cannot find it.

Thanks.

We are running community web site with medium of 2000-3000 visits per day, according to Google Analytics.
We used dedicated server AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ with 2GB RAM

mysql Ver 14.7 Distrib 4.1.11, for pc-linux-gnu (x86_64)
Here is my.cnf file

We upgraded to: AMD Athlon(tm) 64 X2 Dual Core Processor 6000+, With 8 GB DDR2 RAM

mysql Ver 14.12 Distrib 5.0.32, for pc-linux-gnu (x86_64) using readline 5.2
Here is my.cnf file
We upgraded Drupal from 4.7.x to 5.x.

The problem:
On the old server we didn’t experienced any problems with mysql, instead on the new machine.

After this upgrade we have serious MySQL overload
On the new machine performing top via SSH I see:

top - 13:44:30 up 50 days, 17:28,  2 users,  load average: 0.37, 0.56, 0.67
Tasks: 139 total,   2 running, 136 sleeping,   0 stopped,   1 zombie
Cpu(s): 19.4%us,  7.8%sy,  0.0%ni, 72.8%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   8151860k total,  7297572k used,   854288k free,   262260k buffers
Swap:  2097140k total,       24k used,  2097116k free,  5648848k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
29872 mysql     15   0  429m 183m 5812 S   30  2.3   2024:32 mysqld

Hi there,