Disabling Prefetch



  • Hello --
    I am new to the forum, although I have been using Vivaldi for nearly a year. I also run Firefox and Chromium, all on Linux Mint. Vivaldi is fast becoming my favorite, due to its organizational tools.

    While I have done a great deal of fine tuning to Firefox and Chromium, I am not finding as many available options/switches as in the other browsers. I have searched the forums here, as well as the web in general, but don't have all the answers I need. I am hoping more-experienced Vivaldi users can provide some help with these questions:

    1. Does Vivaldi do DNS and link prefetching? If so, is there any way to disable them (such as switches/flags)?

    2. I see that Vivaldi offers "NoState Prefetch," which appears to be a modified form of prerendering. I would probably prefer to disable that, as well. I found a flag for that, but the status is marked only as "Default." What is the default: Enabled or Disabled? The flag page warns that these options are risky to enable, so I should probably mark this "Disabled," right? That is what I would prefer anyway.

    3. Do all modes of prefetching write only to memory (RAM) cache, or do they write anything to disk?

    4. Does running in incognito mode change the behavior of the various prefetch activities (disable them, or change where or what they write)?

    For controlling these sorts of "behind the scenes" activities, Firefox seems to give the most straightforward granular control. Chromium is a bit more difficult, and Vivaldi seems to hide some of what Chromium does offer. Perhaps I am overlooking some hidden treasures, and I hope this forum may offer some guidance. Thanks in advance!



  • If I'm not mistaken you can toggle fetching resourced by going to chrome://settings and disabling "Use a prediction service to load pages more quickly".

    I don't know enough about it to answer your other questions though.



  • Thanks very much for responding!

    Yes, there are "Advanced" settings in chrome/chromium (2 of them, actually) that enable me to switch off prefetching (link and DNS). But I cannot find those in Vivaldi. When I try chrome://settings in Vivaldi, it automatically changes to vivaldi://settings, and there is no "Advanced" settings section containing the "prediction service" options.

    As mentioned earlier, I also tried vivaldi://flags, where I found only the "NoState Prefetch" option, which - according to the Chrome people - is actually a streamlined prerendering. There are no flags for normal DNS prefetch or link prefetch. So I am still seeking a way to disable those services, which I like to do under certain circumstances.



  • @iggy64 strange. I see the chrome settings when I type it in the address bar.

    What if you select this text: chrome://settings and right click, then select "Go To..."

    You can then go into advanced settings to change it.



  • Thanks so much for sticking with me on this. I tried what you suggested and still was unable to see the Advanced Settings -- or even the basic settings, for that matter.

    But the fact that you assured me it could be done was all I needed. I thought about what I might be doing differently from what you are doing. I wondered if the fact I was in incognito mode made the settings invisible. And that was it! I relaunched Vivaldi in NON-incognito mode and - voila - the settings appeared.

    So I can now select "Use a prediction service to load pages more quickly."

    I have read that: "Also known as 'prerendering', the Prefetch feature in Google Chrome will cache pages that are linked on the web page you are currently on. This allows the page to load a bit faster when accessing it."

    So I conclude that this is Link Prefetching, and I can now disable it when I want to. It is unclear whether Chrome/Vivaldi also does DNS Prefetching, which Firefox apparently does.

    The other predictive feature Chrome/Vivaldi apparently offers is predictive completion of URLs and search terms. That can be disabled via the "Use a predictive service to help complete searches and URLs typed in the address bar" setting.

    Thank you again, for emphasizing that these settings really do exist in Vivaldi, as I was about to give up on this. The trick was realizing that incognito mode hides virtually all the settings.

    Next I will try to find out:

    • where Vivaldi caches the linked web pages, and

    • whether incognito mode changes the behavior of these predictive services (prefetch) -- in terms of how much it writes, and where it writes

    Thanks again!



  • I have discovered that:

    It is unclear whether both of these ideas are correct, and that the same setting enables or disables both types of prefetching.

    I'll keep digging.



  • @iggy64
    Hi, strange, I have "Prediction" and "Advanced" in Vivaldi://settings.
    Wich version of Vivaldi do you use?

    0_1543308974733_728a902e-8abd-4e73-b96d-573adb466416.jpg

    Check vivaldi://settings/?search=prediction

    Cheers, mib



  • @mib2berlin you made the common copy paste error regarding the settings pages - the correct internal url is chrome://settings/?search=prediction
    ; )



  • @zaibon
    Ooops, yep. bomb

    Mib



  • Hi mib2berlin,

    Thanks for responding. I don't know if it matters at this point, but - to answer your question - I am using v 2.1.1337.51 32-bit Linux. I believe that is the up-to-date version for my Linux Mint 17.1 distro.

    As noted earlier (and documented with links), I discovered that Chromium (and, presumably Vivaldi) does both DNS and link prefetching (although it calls the latter "prerendering"). The Advanced Settings menu provides only the one option ("Use a prediction service to load pages more quickly") to disable prefetching. Some references say this toggles DNS prefetch, while other references say it toggles prerendering (link prefetch). Perhaps it does both, and I am still digging into this.

    Meanwhile, I am still trying to find out whether incognito mode changes prefetching behavior -- either by disabling it completely, or by changing where it caches the information. This question seems a tougher challenge so far.


 

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