Does the system process slow down my Database access? I have a Fairly large DB containing mostly html documents. I wrote a python script that fetches always 1000 html documents at once from my database cur.execute("SELECT id,url,html_file FROM html ORDER BY id OFFSET %s LIMIT %s;" % (offset, limit)). Afterwards I do a bit of regular expression on the html documents. Because I have a lot html files to go through I track the time how long each step takes. For the first 4000 times retrieving the html documents from the database took around 3 seconds. Now it is up to 4 Minutes. I'm running a Windows 7 machine and took a look at the Resource Monitor. The Database is on its own HDD with nothing else on it. But in the Resource Monitor i could see that the System Process constantly reads something  out of my Postgres Folder

Image   PID File    Read (B/sec)    Write (B/sec)   Total (B/sec)   I/O Priority    Response Time (ms)
System  4   E:\PostgreSQL\data\base\10596207\10598404.1 13,855,193  0   13,855,193  Normal  9
System  4   E:\PostgreSQL\data\base\10596207\10598404.1 11,182,442  0   11,182,442  Normal  9


so the question is is this normal or is the system process the culprit here and how do I stop it? (malware and virus scanning are disabled as well as search indexing)

I followed the advice from Reaces and found that superfetch was already disabled. But I also downloaded the process explorer from sysinternals and there I observed something strange. After about the same amount of parsed html documents (about 4,513,000 fetched in package of a 1,000 from the database) the postgres process begins to write a lot of stuff to the HDD up to this point it did read ~3TB from disk and write ~100mb.

But now about 3000 html documents later the process explorer shows me that the postgress proces did write 10GB to the HDD with heavy write access for every cur.execute("SELECT id,url,html_file FROM html ORDER BY id OFFSET %s LIMIT %s;" % (offset, limit)) command

What is the database doing and how do I stop it? my best guess is that the database orders it self to be more efficient the next time but that does not help me now.
One of the common disk usage process on a windows 7 machine under the System process is Superfetch.
You might want to look into disabling it disabling superfetch.

The reason why it's likely Superfetch is because you're seeing 


Only reads
It's not your OS disk
You're running windows 7, not a server version
more slowdown as the amount of files increases


If that doesn't help Sysintenals' Process Explorer might help you get a better idea of what's going on. sysinternals