grep with --extended-regexp much slower on Ubuntu 16.04

[Brian Bird]

On Fri, 9 Feb 2018 16:23:42 -0600, C de-Avillez wrote:
>Perhaps (in fact, probably) related to bug 26193 on grep? Please see 
>the thread on this at [1]. The fix was included in grep 3.1.
>[1] https://lists.gnu.org/archive/html/bug-grep/2017-03/msg00009.html

I just tried grep 3.1 downloaded from the artful repository and that seems to fix it:

# dpkg -i /tmp/grep_3.1-2_amd64.deb
# openssl rand -out /tmp/random.txt -base64 100000000; time grep --extended-regexp "[0-9]{10}$" /tmp/random.txt
real    0m0.413s
user    0m0.368s
sys     0m0.040s


Strange Ubuntu have left such a bug in a LTS release. At first glance it doesn't look like this causes any obvious compatibility problems, so I may stick with it. Thanks for all your help/suggestions!

Brian