How Does Google's "index" find the location of pages in the "page directory" to return?
-
This is my understanding of how Google's search works, and I am unsure about one thing in specific:
- Google continuously crawls websites and stores each page it finds (let's call it "page directory")
- Google's "page directory" is a cache so it isn't the "live" version of the page
- Google has separate storage called "the index" which contains all the keywords searched. These keywords in "the index" point to the pages in the "page directory" that contain the same keywords.
- When someone searches a keyword, that keyword is accessed in the "index" and returns all relevant pages in the "page directory"
- These returned pages are given ranks based on the algorithm
The one part I'm unsure of is how Google's "index" knows the location of relevant pages in the "page directory". The keyword entries in the "index" point to the "page directory" somehow. I'm thinking each page has a url in the "page directory", and the entries in the "index" contain these urls. Since Google's "page directory" is a cache, would the urls be the same as the live website (and would the keywords in the "index" point to these urls)?
For example if webpage is found at wwww.website.com/page1, would the "page directory" store this page under that url in Google's cache?
The reason I want to discuss this is to know the effects of changing a pages url by understanding how the search process works better.
-
Yeah that makes sense. I also have a lot of experience with databases and the back ends of websites so I know your language.
I'm wondering how Google correlates the url with the page entries then. Maybe each page entry would have a url field so Google knows the location of the live version to constantly update that entry in the "page directory" database?
-
That is a question that no one here can answer. We cant speak for how Google does things internally.
but.... as a web / database programmer for 14+ years let me tell you how its "generally" done
Usually when you have to link to separate sets of data together (ie. database or tables) there is usually a unique_id created to link them which usually is never changed. So when a new record is created that record will live with that ID for its life, also known as a (unique identifier which tends to be an auto-incremented number that is dynamically generated and can not be repeated).
Since records tend to be linked this way, any other fields that exist in the record (firstName, lastName, Url, blah blah) then can be changed without the original ID being disturbed.
So to answer your question from my experience I would assume Google links from a unique identifier of some sort and not the URL directly.
Hope I didn't lose you, its my favorite subject...but no one here speaks that language to much
-
That makes sense, thanks for getting back to me so fast!
Perhaps you can help answer my next question. I have a client who used to host his domain at "www.oldurl.com", and has migrated his website to "www.newurl.com". He wants to use his old domain "www.oldurl.com", so he setup forwarding/masking so that when someone tries to access "www.oldurl.com" they are forwarded to "www.newurl.com" but the url shown to the user is "www.oldurl.com".
My client want his old url "www.oldurl.com" to be ranked in Google, but from what I understand his new url will be ranked. I know masking is really bad for SEO, and I want to educate my client as to why on the technical side. I have read Google see's all the content as duplicate with masking. Do you know the details as to why?
-
Hey Cesar,
Thanks for the links! Really useful info there.
Unfortunately they I couldn't find the answer I was looking for so I'll be more specific in what I'm asking.
From what I understand Google uses two database systems. One contains keywords and the other contains cached pages. How does a keyword entry point to a page entry? Does it use a unique id number, or does it use the url that page is using in the "live" vesion on the web?
-
Just because you create a new page and delete the old one, Google won't know immediately about it. So if Google crawls the new page before it's had a chance to crawl the old one, then it will indeed consider the new page to be duplicate content. Then when it tries to crawl the old page, it will discover that it no longer exists. However, as long as links to the old page exist, it will continue to try to crawl that page. Eventually it may de-index the old page if it keeps returning an error.
Bottom line, if you are moving content to a new URL, be sure to include a 301 redirect on the old page so that Google (and other search engines) know that the piece of content has moved. You can also do this with canonical tags, but 301s are more effective.
-
Thanks for the response and links Takeshi. Maybe I can rephrase the question to be more clear. Let's say a piece of content (or page) is at the url "www.oldurl.com/page". During a migration this same piece of content now at the url "www.newurl.com/page". The "www.oldurl.com" doesn't exist anymore so there isn't duplicate content in the live web.
Would Google create a new entry in it's "page directory" (what is the industry standard name for this directory?) and give it the url "www.newurl.com/page"?
If it does create a new entry, would Google keep the old entry "www.oldurl.com/page" although the old url doesn't exist in the "live" web anymore?
-
Wow you just asked questions that would require about 10,000,000,000 answers
Lets start here
- Video from the man himself Mr. Matt Cutts - Matt Cutts (Works for Google)
- Great Web 2.0 Page create from Google themself - (Google Them self)
- Older but still relevant description about how "backlinks" affect PR - (Google Them self)
-
This a pretty confusing question, and the terminology you use is different from industry standard. Check out these links for a quick overview of how Google works:
- http://www.google.com/insidesearch/howsearchworks/thestory/
- http://www.googleguide.com/google_works.html
If you are just worried about changing a page's url, just be sure to put in a 301 redirect from the old page to the new page. That way, even if Google has an older version of the page indexed, it will automatically redirect the user to the new page as well as help Google discover the new location of the page.
Got a burning SEO question?
Subscribe to Moz Pro to gain full access to Q&A, answer questions, and ask your own.
Browse Questions
Explore more categories
-
Moz Tools
Chat with the community about the Moz tools.
-
SEO Tactics
Discuss the SEO process with fellow marketers
-
Community
Discuss industry events, jobs, and news!
-
Digital Marketing
Chat about tactics outside of SEO
-
Research & Trends
Dive into research and trends in the search industry.
-
Support
Connect on product support and feature requests.
Related Questions
-
I'm struggling to understand (and fix) why I'm getting a 404 error. The URL includes this "%5Bnull%20id=43484%5D" but I cannot find that anywhere in the referring URL. Does anyone know why please? Thanks
Can you help with how to fix this 404 error please? It appears that I have a redirect from one page to the other, although the referring page URL works, but it appears to be linking to another URL with this code at the end of the the URL - %5Bnull%20id=43484%5D that I'm struggling to find and fix. Thanks
Technical SEO | | Nichole.wynter20200 -
Any idea why pages are not being indexed?
Hi Everyone, One section on our website is not being indexed. The product pages are, but not some of the subcategories. These are very old pages, so thought it was strange. Here is an example one one: https://www.moregems.com/loose-cut-gemstones/prasiolite-loose-gemstones.html If you take a chunk of text, it is not found in Google. No issues in Bing/Yahoo, only Google. You think it takes a submission to Search Console? Jeff
Technical SEO | | vetofunk1 -
"Cookies are required to access this site" in Google Serp?
One of my clients is having an issue where their Google search result title and description are just showing "Cookies are required to access this site." instead of the actual meta values. The problem is only in Google as Yahoo and Bing seem to be fine. You can see in the image below or by running a search your self for "be well bodyworks longmont" I've never seen anything like it and couldn't find any reference to anyone else having this issue... I would very much appreciate any insight as to what is going on. Thanks! c5PGL
Technical SEO | | CampfireDigital0 -
How to de-index a page with a search string with the structure domain.com/?"spam"
The site in question was hacked years ago. All the security scans come up clean but the seo crawlers like semrush and ahrefs still show it as an indexed page. I can even click through on it and it takes me to the homepage with no 301. Where is the page and how to deindex it? domain/com/?spam There are multiple instances of this. http://www.clipular.com/c/5579083284217856.png?k=Q173VG9pkRrxBl0b5prNqIozPZI
Technical SEO | | Miamirealestatetrendsguy1 -
Where did the "Location" go, on Google SERP?
In order to emulate different locations, I've always done a Google query, then used the "Location" button under "Search Tools" at the top of the SERP to define my preferred location. It seems to have disappeared in the past few days? Anyone know where it went, or if it's gone forever? Thanks!
Technical SEO | | measurableROI0 -
Website's stability and it's affect on SEO
What is the best way to combat previous website stability issues? We had page load time and site stability problems over the course of several months. As a result our keyword rankings plummeted. Now that the issues have been resolved, what's the best/quickest way to regain our rankings on specific keywords? Thanks, Eric
Technical SEO | | MediaCause0 -
Google indexing page with description
Hello, We rank fairly high for a lot of terms but Google is not indexing our descriptions properly. An example is with "arnold schwarzenegger net worth". http://www.google.ca/search?q=arnold+schwarzenegger+net+worth&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a When we add content, we throw up a placeholder page first. The content gets added with no body content and the page only contains the net worth amount of the celebrity. We then go back through and re-add the descriptions and profile bio shortly after. Will that affect how the pages are getting indexed and is there a way we can get Google to go back to the page and try to index the description so it doesn't just appear as a straight link? Thanks, Alex
Technical SEO | | Anti-Alex0 -
Existing Pages in Google Index and Changing URLs
Hi!! I am launching a newly recoded site this week and had a another noobie question. The URL structure has changed slightly and I have installed a 301 redirect to take care of that. I am wondering how Google will handle my "old" pages? Will they just fall out of the index? Or does the 301 redirect tell Google to rewrite the URLs in the index? I am just concerned I may see an "old" page and a "new" page with the same content in the index. Just want to make sure I have covered all my bases. Thanks!! Lynn
Technical SEO | | hiphound0