Dynamic urls and dupe pages

Just a warning for fellow webmasters here and a suggestion for Google.

[jaski]

abc.com?x=a&y=b

abc.com?y=b&x=a

Google is indexing both from my site. I have a database driven site which generates 400 or so such pages. It happened by a mistake in my code that I changed the order of variables in query string. Now google has indexed both and has 800 pages in the index and googlebot is again requesting both versions.

I am afraid this can lead to a dupes penalty down the line .. but I guess their *algo should be able to see* that these urls cannot be different ..

[shaadi]

Interesting case,

IMO Google will drop the URLs, which do not exist now!

[gsx]

You could write your code so that if the variables are passed in one format, you send a permanently redirected message, so the variables are resent the correct way around.

Google will not index them twice then, but I do agree that that seems to be a Google problem that could affect your site.