FireFox STOPS saving session store backup!

Question

For a few years it's a VERY BIG problem with FireFox!
It STOPs session saving after a while.
IT IS NOT a plugin problem!
IT IS NOT a settings problem!
IT IS NOT a my stupidity problem!
IT IS SERIOUS PROBLEM in FIREFOX CODE!
I do use Firefox..... NO! I do use all the mainstream browsers since first versions of Netscape and IE born!
In my PCs all 5 current mainstream browsers are installed - IE, FF, Chrome, Opera and Safari (for Win)
All these browsers have their own pros and contras and all they are in use concurrently or momentarily.
Mostly used are FF and Opera. Chrome is less used (due to its extremal privacy violation). IE is used for particular purposes primarily ActiveX related, and Safari is rarely used for checking compatibility.
I'm using FF since v!.x or 2.x
I have 14 FF profiles in my FF AppData folder and I KNOW WTF I SAY!
I can't particularly remember what FF version was firstly appeared to be fault, but it was i long ago. A few years ago. I can definitely say it wasn't some of stable 3.x versions.
Usually I have hundreds of tabs opened at the moment. (Maximum counted is about 370 and it was Opera 9.x on the PC w/1.5GB of RAM)
It's not a 'quantity' game. I do read hundreds of pages every day and forced to open more and more tabs looking for additional info. I can't close many tabs before I will have complete problem description in my mind and can point and save just a valuable info, which really helps to solve problem. Frequently I should solve a few problems at the same time. While some info is inaccessible or not yet found I switch to another problem and trying to solve it. It's a job and creative process.
I was very discouraged when I lost a few hundreds of tabs 1st time (since great recovery options first time appeared in browsers). I thought the problem is random, later I thought the problem will be solved in the next releases of FF because it's unbelievable that millions of peoples in the world are using FF and no one have reported such a serious bug. Later I just tried to save sessionstore files manually in the middle of work. I don't like to complain neither ask for help. At first I do my own research and trying to help others with many complicated things. But this problem too complicated for me. FF's sources should occupy a few hundred megs. I should spend at least months to explore code w/o any warranty I could fix the problem. It's too expensive... People who develop this code can fix it many times faster end easier.
When I saw FF changed session recovery format (which means for me complete module rework) about a year ago and hoped the problem will now should be completely resolved, but NO! It was not resolved in any way.
I'd experienced this problem ALWAYS with any version of FF (for at least a few years), on ANY PC (I have a few decades) and any modern Windows OS (XP/V/7/32/64/etc), with a 500MB profile with a few plugins installed and with completely new and clear default profile!
Just try yourself. Setup new profile and work a few days or weeks on any theme(s). Do not close tabs (at least ones, which you wanna explore once more). If your PC has 2-4Gb of RAM you will notice FF stopped to save session info after you will have a 50-100 tabs opened (you'll see sessionstore.js or session-backups\*.js script files reached 15-20-30MB long and stopped to change and it's LastMod date/time(s) are frozen) and after the moment some stupid most probably Ad-related and most probably "Java related" script will hang your FF you will notice all recent tabs (opened a few minutes or a few days ago) gone from recovery.
I just lost a two days of hard work in a 100-200 tabs related on rare player HW/SW recovery and modding (but God saved a few hundred of previous tabs related to some mobile hacking). I've noticed FF started to hang more and more and checked previous.js, recovery.bak, recovery.js was last modified on Apr, 14 but today is Apr, 16! I've lost one more hour trying to save tabs, even installed Session Manager, promised session saving on user demand but after a half hour of action against hanging FF, plugin showed me that I have NO ONE tab to save. I've managed to copy a few URLs to the text file before FF have completely fallen.
FF is less RAM consuming but more exposed to CPU overload than WebKit based Chrome and Opera. Safari for Win is just a bunch of bugs. Old Presto based Opera was really fast and resource effective but it was dropped due to "technology" requirements. Chrome and Opera save session info reliable (only rare random problems could occur), but they fall sooner because of RAM overload. And certainly FF has best plugin collection which overcomes Crome's and especially Opera's.
On other hand Opera has integrated Session manager and you can save all or particular tabs and windows at any moment.
Sure such feature should be integrated to all browsers. It should be reliable, made at native C level, not at limited and unreliable JS/plugin level as it done in FF Session Manager plugin. User should have an option to save his work at any moment and in any situation, then open it anywhere. Cloud sync can not be offered as the only option. There are many security related objects around and I will never send them (by my will) to any clouds except ones made and completely controlled by me or my structure. I've enough hardware, knowledge and other resources to save my data on my own storage. :)
On my hand today there are too much "technologies" around. That's ENOUGH!
Reliability and resource economy should be preferred as the main goal!
If someone of devs is ready to spend enough time and fix this really annoying and resource consuming issue feel free to contact me and tell me what logs to collect on event.
P.S. It's time to appear some JS-ProcessExplorer (executed scripts manager) for Browser. Scripts became too powerful, resource expensive and aggressive.
AdBlock can't eliminate all (btw it's main goal is Ads).
There should be the way to explore and kill particular scripts by hand, ones which hang and other way disturb stability of browser and user's work! I see no other way out.

Answer 1

Okay, that's a lot of information. I think the key part for support purposes is this:
''TheDrive [[#question-1057777|said]]''
<blockquote>
Just try yourself. Setup new profile and work a few days or weeks on any theme(s). Do not close tabs (at least ones, which you wanna explore once more). If your PC has 2-4Gb of RAM you will notice FF stopped to save session info after you will have a 50-100 tabs opened (you'll see sessionstore.js or session-backups\*.js script files reached 15-20-30MB long and stopped to change and it's LastMod date/time(s) are frozen) ...<br><br>
... I've noticed FF started to hang more and more and checked previous.js, recovery.bak, recovery.js was last modified on Apr, 14 but today is Apr, 16! I've lost one more hour trying to save tabs, even installed Session Manager, promised session saving on user demand but after a half hour of action against hanging FF, plugin showed me that I have NO ONE tab to save. I've managed to copy a few URLs to the text file before FF have completely fallen.</blockquote>
You're not the first person to report that the sessionstore.js or recovery.js file stopped updating with new activity. However, it's rare enough that I can't recall whether we have gotten to the bottom of it in a previous thread. I'll see whether I can search it up.
Meanwhile, someone might be able to come up with a way to watch for problems and extract some debug information, but I'm not personally familiar with such tools.