update index

if a page has updated, so google should recache it and index it again.
but google how to decide if the page is updaged?

 

They (probably) compare a hash* of what they crawl and what they already have. If they aren't 100% the same, they know they should update.

* like a fingerprint/scan

 

they probably might just put the information they saw into their database not really comparing. if you did not update your info. the information in the database will stay same and show the same thing. but if you updated it, the new content will just replace the old one in database and shown in the search result. ^^ (more likely scan the whole pages then print out in a paper and put new paper ontop of the old version they got.)

 

Yeah I doubt they do any comparison, they probably just straight up replace the entire page in their index when they re-crawl your site. The crawl time for each site varies, so it may not show up for a bit in their index once you change it.

 

If you see a problem that it doesnt update you can also submit for the page to be deleted in google tools then resubmit a new sitemap

 

I could not tell you how it works. I have a blog that is updated by me a few times a week and it has not been updated or crawled by Google since Feb. I tried sitemaps, resubmit and everything and still can't get it to update. If you figure it out, please let me know.

The rest of my sites and blogs update all the time.

 

How often is "all the time"?

-Matt

 

At least once a week. I have one site and four blogs and all the blogs are on blospot. I just have one that never gets updated.

 

when google crawls your web sites, it takes a new snapshot of the pages . it will upgrade the new cache with the old

 

Cool, thanks!

-Matt

 

i think when it will be plain html file updation google uses just header info received from the server to check the file is changed from last time.

but if it is the case of dynamic pages like .php, .pl etc it has to fetch the page every time whether the page is updated or not.

i dont know what happens if apache mod rewrite is used for .htm/l file urls.

hope i'm right.

nb

 

But I think google crawl the site even its not updated and recache it.

 

cache takes time to update sometimes

 

try to put that blog on DP sig and let see it still didnt get index or not. We always say put it in DP sig. try out and tell us the result. ^^

 

ofcourse google owns blogspot, easily crawled...

 

I think google is just re-crawling the website and just adding and changing the information when it differs.

 

More PR sites are updated more often than lower pr probably. Besides that, there are some comparsion methods, to get know whether site is updated or not.

 

re-indexing takes time.

 

Been there for months and also it is the blog in the feed next to my name. I also have listed it in at least a few hundred directories, on all my otehr blogs and my PR3 website. It is also my oldest blog. Google just quit coming on Feb 17th and I check webmaster tools all the time and still the same.