Database is locked by another process

[mac230]

Expected or desired behavior

I would like to use mu4e to view/manage/read email.

Actual behavior

Calling 'mu4e' always yields the following error message (even after system and emacs restart):

error in process sentinel: mu4e~proc-sentinel: Database is locked by another process
error in process sentinel: Database is locked by another process

Steps to reproduce

Call 'mu4e' in emacs.

Versions of mu, mu4e/emacs, operating system etc.

mu/mu4e 1.2
GNU Emacs 25.3.50.2 (x86_64-pc-linux-gnu, GTK+ Version 3.22.30)
ubuntu 18.04

Any other detail

I followed the instructions at:
https://groups.google.com/forum/#!topic/mu-discuss/EncdNPKhUYo
#8

The solution:

rm -rf ~/.mu/xapian && mu index

didn't change anything for me.

I can run the following from the command line:

mu index -m 
mu index --rebuild -m 

w/o an error message.

I can also run 'mu4e-update-mail-and-index' w/o an error message.

So, basically, I can't get to the mu4e headers. I've been using mu4e on a mac for several years and am using essentially the same config on this system.

There were a couple of discussion of possible .lock files. Could you elaborate on what to look for. On my system:

find /home/ -iname "*\.lock*"

shows the following:

/home/mahlon/.emacs.d/.emacs.desktop.lock
/home/mahlon/anaconda3/pkgs/jupyterlab-1.1.4-pyhf63ae98_0/site-packages/jupyterlab/staging/yarn.lock
/home/mahlon/anaconda3/lib/python3.7/site-packages/jupyterlab/staging/yarn.lock

I don't think any of these are related to mu/mu4e.

Any help much appreciated. Thanks.

[djcb]

Hmm, something must have opened the database, that's why you're getting that error message. What does

lsof  2>/dev/null | grep xapian

give you when you run it before you start mu4e?

[mac230]

No output of that command before or after starting mu4e.

Forgot to mention that I'm using mbsync and msmtp w/ mu/mu4e as well.

Tried removing all messages and re-building the mail dir w/ no results after reading the discussion here:
#198

My command to make the mail dir:

mu mkdir ~/mail

[djcb]

Rebuilding etc. won't really help here, I think.

It's about another process having the xapian database open for writing which makes mu4e error out. For instance you cannot run mu4e while running mu index (or vice-versa).

So perhaps try immediately after you get that error:
lsof +D /home/mahlon/.mu

Perhaps you have some other script running mu index in the background?

[mac230]

No output from

lsof +D /home/mahlon/.mu

I tried:

lsof +D ~/.cache/mu

which returned the following:

COMMAND  PID   USER   FD   TYPE DEVICE SIZE/OFF     NODE NAME
bash    7335 mahlon  cwd    DIR  253,1     4096 10094321 .
lsof    8226 mahlon  cwd    DIR  253,1     4096 10094321 .
lsof    8227 mahlon  cwd    DIR  253,1     4096 10094321 .

Also, no other scripts running mu index.

[mac230]

I deleted everything I could find related to mu and mu4e and rebuilt/reinstalled. It seems to be working now. I couldn't track what was actually causing the issue, but am closing since I have the desired behavior now. Thanks.

[djcb]

Hmm good that it works, even if we don't know why!

If it ever happens again, perhaps check if the .lock exists before starting mu4e.

[johnhamelink]

lsof +D ~/.cache/mu

which returned the following:

COMMAND  PID   USER   FD   TYPE DEVICE SIZE/OFF     NODE NAME
bash    7335 mahlon  cwd    DIR  253,1     4096 10094321 .
lsof    8226 mahlon  cwd    DIR  253,1     4096 10094321 .
lsof    8227 mahlon  cwd    DIR  253,1     4096 10094321 .

Once I knew the process ID, all I had to do was kill it, run mbsync, and then run M-x mu4e as normal, and all was well again - I thought I'd add a comment here for anyone who comes across this issue in future.