Recently, I was actually searching for some pdf documents on Google. My search query was:

conditions for view Serializability

The result page looked like this:

enter image description here

The first result was exactly what I needed.

Now, expecting more documents regarding this topic I tried visiting this page.

There were lots of PDFs that were related and not related to it. It was all messed up so I decided to use Google again for the result I wanted.

I put up the query:

 site:http://infolab.stanford.edu/~ullman/ filetype:pdf

Now yes! I got so many PDF pages in the result. But since I wanted more about the topic "Serializability", I changed the query to:

site:http://infolab.stanford.edu/~ullman/ filetype:pdf serializability

Then it gave me around 5 results!

enter image description here

To my wonder, the result which I got in my very first search was not there in the result page!

I know there isn't much to research about his topic but since I have lots of free time, was wondering about what I missed!

2 Answers 2


It's interesting that if you remove ~ullman from the site you get your first result returned at the very top of the search results again!

 site:http://infolab.stanford.edu/ filetype:pdf view serializability

Browsing around Professor Ullman's page, I noticed that there were no (live) direct links to the original vs-old.pdf file that was at the top of your original search. I'm guessing that if you are restricting results to Professor Ullman's section of the infolab site, there will be no results returned, whereas there are likely to be other pages in the infolab that contain links to that particular document - which results in that pdf reappearing when submitting a less restrictive search.

  • So i think rather than depending on the location of the file, google is restricting the search result with the back-links from that page! I meant though the location is inside professor ullmans page , it should be backlinked from some other location in infolab.stanford.com !
    – qwerty123
    Commented Nov 18, 2011 at 8:51
  • *the worst thing I cant understand is that why I was DOWNVOTED in superuser for this question!
    – qwerty123
    Commented Nov 18, 2011 at 8:57

First query searches for word view-Serializability as indicated by the bold terms.

Your last query searches for only Serializability. Seems Google considers view-Serializability as a single word and doesn't consider Serializability as per of view-Serializability. So that is skipped out.


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