Why can’t I use the Facebook confirm identity recovery process for lost access to 2FA?


I have managed to loose access to my Facebook account/Messenger by accidentally logging out all connected devices when doing something on the Messenger app (can’t remember which action; possibly changing password).

I had at that point already deactivated my account, but continued to use Messenger. Problem is, I never connected my phone-number to my account, nor have I written down the backup-codes for 2FA or linked a third-party code generator.

The problem when trying to recover

However, when I now try to log in and get the prompt to enter 2FA code, I click the “Need another way to authenticate?” link and then “Other options” -> “Get More Help” which leads me to “Confirm your identity” where you’re supposed to be able to upload gov-issued ID and email.

At step 1 “How can we reach you?” i enter my email and click send, and it fails 500 server error and the process stops there (see image below).

Official support

I have tried to get in touch with FB, but it seems to be impossible. Nor have any of the help-center articles worked; “report” account via friend, clear all browser cache, etc.

Are there any other ways to contact FB and get manual assitance with this, or are there known reasons for this error?

500 server error when trying to send contact email

pr.probability – Space of functions and the Coordinate process

I have the following question:

Let a probability space $(Omega,mathcal{F},mathbb{P})$ with a stochastic process $X$ be given and define $(mathcal{F}_t) = sigma(X_t;t geq 0).$
Further, we have the map $phi: Omega rightarrow mathbb{R}^{(0,infty)}$ given by $phi(omega) = (t mapsto X_t(omega)).$ Let $Y$ denote the coordinate process on $mathbb{R}^{(0,infty)}$. Is it possible to show that $phi^{-1}(sigma(Y_t; t geq 0)) = (mathcal{F}_t),$ i.e. for every $F:Omega rightarrow mathbb{R}$ which is $(mathcal{F}_t)$-measurable there exists an $f:mathbb{R}^{(0,infty)} rightarrow mathbb{R}$ with $F(omega) = f(phi(omega))$

4Tb drives not working using the same backup process that works with 2Tb ones

I’ve been using a icybox 2 bay raid box for backing up my work for some years without any problem. I use WD 2Tb 3,5 drives in Raid 1 mode.

This year i started using 4Tb drives of the same brand. For my surprise, the drives can only be accessed when they are both in the icybox, not individually when i put them in a sata docking bay as i always did with the 2Tb ones.
When i connect the drive the mac says it can’t access the drive. I’ve run first aid in disk utility but didn’t work either.
I’m using macbook pro M1, disks are formatted in Mac OS Extended (Journaled), Big Sur 11.5.2

Already checked with different cables, docking bays, external drive enclosures, etc…


licensing – How to check the process limit on the license of mathematica?

My current calculation need to launch multiple mma kernels in our institute’s cluster. However, if I launch too much tasks, there will be an error massage as following

“The $-process limit on the license you are trying to run has been reached. Contact Wolfram Research or an authorized Wolfram product distributor for information on upgrading your license configuration.”

The $n is the process limit of my account.

Of cause, I can know this $n if I see this error massage. Is there any function or command in mma that can tell me this limit?

sql server – How to determine the Tipping Point of which Physical Join Operator gets used to process a query?

I’ve been noticing some strange occurrences lately on my development SQL Server instance where the Nested Loops Physical Join Operator is used when a Hash Join would be much more efficient, within a multitude of different queries on my server. One example I encountered was where the two datasets are in the thousands and millions, and producing resultant datasets in the billions after joined.

Evidently using the query hint HASH JOIN improves the performance in each case so far, but I’m trying to understand what factors are generally / globally involved that affect the tipping point of which physical join operator is used.

I’m starting to wonder if my database, the SQL Server instance, or the server provisioned for it are potentially configured in an unusual way. (I’m thinking this for a number of other performance oddities I’ve run into so far as well, but I’m not quite ready yet at trying to determine the root cause.)

So, I’m just wondering what factors are use to determine the tipping point of which physical join operator is used, and how can I determine what the value of that tipping point is in my SQL Server instance? My understanding is it’s not a fixed value as briefly mentioned in this article on adaptive join regression.

Traditional Tipping Point:
There’s a tipping point where the plan will change from a hash join to
a loop join if we filter out a single additional row. On my machine,
the tipping point is between 48295 and 48296 rows

stochastic processes – On the generator of a Markov process

This is a (probably basic) question about the generator of a Markov process.

Let $(E,d)$ be a locally compact metric space. We consider a Feller process $X=({X_t}_{t ge 0},{P_x}_{x in E})$ on $E$.
That is, for any $t>0$, the semigroup $P_t$ of $X$ maps $C_{infty}(E)$ into itself. Here, $C_infty(E)$ denotes the space of continuous functions on $E$ vanishing at infinity.

We assume that the generator $L$ of $X$ is described as follows: for $f in C_{infty}(E)$ and $x in E$,
Lf(x)=int_{X setminus {x}}(f(y)-f(x))c(x,y),mu(dy).

Here, $mu$ denotes a Radon measure on $E$, and $c(x,y)$ a nonnegative bounded function on $E times E setminus text{diag}$ with compact support. Therefore, the Feller processs $X$ is a pure jump process.

For a bounded open set $U$, we define $tau_U=inf{t>0 mid X_t notin U}$. The part process $X^U$ of $X$ on $U$ is defined as
X_t,&quad t<tau_U,\
partial ,&quad t ge tau_U.

We assume also that $X^U$ is also Feller process. Then, can we describe the generator $L^U$ of $X^U$?

We write $E_x$ for the expectation under $P_x$, the law of $X$ starting from $x$.
For $f in C_{infty}(U)$ and $x in U$, we have
L^Uf(x)&=lim_{t to 0}frac{E_{x}(f(X^U_t))-f(x)}{t}\
&=lim_{t to 0}left(frac{E_{x}(f(X_t))-f(x)}{t}-frac{E_{x}(f(X_t):t ge tau_U)}{t} right).

Can wa characterized the quantity $lim_{t to 0}E_{x}(f(X_t):t ge tau_U)/t$ in terms of $c(x,y)$ and $mu$?

linux – High CPU from 1 process that’s MYSQLD, but no abnormal queries while doing SHOW FULL PROCESSLIST

I have an issue where 2 processes take 99% of the CPU, but that leaves me the mysqld process that takes 600% of the CPU and a set of php-fpm processes that takes no more than 25% of the CPU according to top (2 process alive and 603 processes sleeping, one of them is the mysqld and the other seems to be a php-fpm, so it’s not coming from too many clients), so I am wondering what might cause the high CPU usage, because doing SHOW FULL PROCESSLIST gives me nothing but a few SELECT commands like 2 or 3, and nothing out of ordinary, how do I find out what’s wrong? I was told it’s the rsync process, but the rsync process should only take a lot of IO and no CPU usage, and the issue is that CPU is at 99% when there’s only 2 process, and doing SHOW FULL PROCESSLIST doesn’t reveal why the CPU usage is so high, so how do you debug this? Is there a command that allows you to check past MYSQL queries, because I was told if there’s a dump to MYSQL it won’t necessary appear when I run SHOW FULL PROCESSLIST, so I am wondering if there’s a way to check all of the queries that were completed recently instead.

systemctl – Cannot kill – nginx: master process nginx -g daemon off

I am setting up both Nginx and OpenRusty on my Ubuntu , one thing confuses me is , even after I quit OpenRusty and stop Nginx , I can still observe a nginx running , seems like this process cannot even be killed , My question is who launch this nginx and why this nginx daemon is always running ?

ps -aux | grep nginx
root      3779  0.0  0.0  10776  6180 ?        Ss   06:57   0:00 **nginx: master process nginx -g daemon off;**
systemd+  4587  0.0  0.0  11172  2756 ?        S    06:57   0:00 nginx: worker process
jia      17315  0.0  0.0  16184  1068 pts/0    S+   07:08   0:00 grep --color=auto nginx

I tried systemctl to stop it , seems nginx still running

sudo systemctl stop nginx.service
 sudo systemctl status nginx.service 
● nginx.service - The NGINX HTTP and reverse proxy server
   Loaded: loaded (/lib/systemd/system/nginx.service; disabled; vendor preset: enabled)
   Active: inactive (dead)

 sudo ps -aux | grep nginx root 3779 0.0 0.0 10776 6180 ? Ss 06:57 0:00 nginx: master process nginx -g daemon off; 
    systemd+ 4587 0.0 0.0 11172 2756 ? S 06:57 0:00 nginx: worker process