Could someone explain why thunderbird creates so many processes per folder

[JD]

For example:

$ lsof | grep Sent
thunderbi 3165           jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Gecko_IOT 3165 3192      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Socket    3165 3193      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
JS        3165 3194      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
JS        3165 3195      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Hang      3165 3196      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Cache2    3165 3197      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Timer     3165 3198      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
gdbus     3165 3200      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
HTML5     3165 3202      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
mozStorag 3165 3203      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Analysis  3165 3204      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Analysis  3165 3205      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
DOM       3165 3211      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Cert      3165 3217      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
URL       3165 3218      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Network   3165 3219      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
mozStorag 3165 3220      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
dconf     3165 3221      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Proxy     3165 3222      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
Cache     3165 3224      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
mozStorag 3165 3228      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
threaded- 3165 3265      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
gmain     3165 3316      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
mozStorag 3165 3386      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
DOM       3165 3773      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
mozStorag 3165 3775      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
MediaMana 3165 3782      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
DNS       3165 4087      jd   37u REG               8,19   3107745   
62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf

$ lsof | grep Inbox
thunderbi 3165           jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Gecko_IOT 3165 3192      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Socket    3165 3193      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
JS        3165 3194      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
JS        3165 3195      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Hang      3165 3196      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Cache2    3165 3197      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Timer     3165 3198      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
gdbus     3165 3200      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
HTML5     3165 3202      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
mozStorag 3165 3203      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Analysis  3165 3204      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Analysis  3165 3205      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
DOM       3165 3211      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Cert      3165 3217      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
URL       3165 3218      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Network   3165 3219      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
mozStorag 3165 3220      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
dconf     3165 3221      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Proxy     3165 3222      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
Cache     3165 3224      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
mozStorag 3165 3228      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
threaded- 3165 3265      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
gmain     3165 3316      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
mozStorag 3165 3386      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
DOM       3165 3773      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
mozStorag 3165 3775      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
MediaMana 3165 3782      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf
DNS       3165 4087      jd   44u REG               8,19   2678870   
62260180 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Inbox.msf

[Gordon Messmer]

On 03/14/2015 04:17 PM, jd1008 wrote:
> $ lsof | grep Sent
> thunderbi 3165           jd   37u REG               8,19   3107745
> 62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
> Gecko_IOT 3165 3192      jd   37u REG               8,19   3107745
> 62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf

PID is the second column.  All of the output you sent was PID 3165.  One 
process.

[Cameron Simpson]

On 17Mar2015 14:51, Gordon Messmer  wrote:
> On 03/14/2015 04:17 PM, jd1008 wrote:
> > $ lsof | grep Sent
> > thunderbi 3165           jd   37u REG               8,19   3107745
> > 62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
> > Gecko_IOT 3165 3192      jd   37u REG               8,19   3107745
> > 62260168 /sdb3/home/jd/.thunderbird/jd1008/Mail/pop.googlemail.com/Sent.msf
>
> PID is the second column.  All of the output you sent was PID 3165.  
> One process.

And also just one file descriptor, merely mentioned many times.

Cheers,
Cameron Simpson

If you do not read the paper, you are uninformed. If you do read the
paper, you are misinformed. - Mark Twain