[Users] Search for messages between timestamps

[Removed GDPR]

Thanks for the explanation Colin.

I checked the files you mention:

[~]: du -Dh /etc/ld.so.cache \
>     /lib/x86_64-linux-gnu/libc.so.6 \
>     /usr/lib/locale/locale-archive \
>     /etc/localtime \
>     /etc/ld.so.cache
196K    /etc/ld.so.cache
du: cannot access '/lib/x86_64-linux-gnu/libc.so.6': No such file or directory
du: cannot access '/usr/lib/locale/locale-archive': No such file or directory
4.0K    /etc/localtime

So only 200Kb of files which will surely be cached on
first read (and are on an SSD drive too).

I also tried this test script which calls the first
one 1000 times to check how long it takes:

#!/bin/bash

for ((n=0;n<1000;n++)); do
    `is-date-in-range 2018-08-05 2018-08-01 2018-08-10`
done

[~]: time ./test

real    0m3.407s
user    0m2.977s
sys     0m0.575s

Then I replaced the `date` calls with fixed values in
is-date-in-range script like this:

current=1533416400
start=1533070800
end=1533934799

which resulted in:

[~]: time ./test

real    0m1.139s
user    0m0.821s
sys     0m0.225s

Obviously there is a difference but even without
hard coding the values the 1000 calls are about 8 times
faster than the 491 calls which CM makes.

Copying the whole folder containing the messages takes
less than a second:

[~]: time `cp -a ~/mail/folder/ /tmp/`

real    0m0.499s
user    0m0.000s
sys     0m0.029s

Extracting the dates only is fast too:

[~]: time grep -riE '^Date:' ~/mail/folder/
...
real    0m0.009s
user    0m0.005s
sys     0m0.004s

So that is a total of 3.407 + 0.499 + 0.009 s. Far
below the ~25 s which CM takes.

How would you explain that? Could there be some
inefficiency in the way CM uses the external command?

--
George