Dear Jan, El 13/11/18 a las 17:09, Jan van den Berg escribió: > Package: grep > Version: 2.27-2 > Severity: normal > > Dear Maintainer, > > I just upgraded from Debian 8 to 9 and noticed that a script which I run > several times per day was really slow: > > real 0m6.384s > user 0m6.288s > sys 0m0.036s > > This used to take well under a second. > > I dug a little deeper and noticed the problem was here: > > grep 'best_bid\|fixed_' /var/www/logs/large_log_file > > Playing around with the grep parameters en locale settings, and narrowed it > down to the regex, because this is way faster: > > grep -F best_bid /var/www/logs/large_log_file > grep -F fixed /var/www/logs/large_log_file > > So much faster in fact, that I can run 2 grep command faster than one. > > real 0m0.199s > user 0m0.108s > sys 0m0.032s > > However, this is strange and unexpected that after an upgrade a > unaltered grep script is slower. I dug a little deeper and it seem related to > #761157 > (and #18454) because of a change in de PCRE library between jessie and > stretch.
I am not sure of that, since you are not using the -P matcher that relies on libpcre3. > > I have not seen a real fix yet (other than altering my script/grep commands), > but I expect the regex library needs work, to match the previous behaviour so > therefore I'm deeming it a 'bug'? … There have been behaviour changes between the version of grep released in jessie and stretch. See e.g. #891086. Could you please run your script with the -a option, and also setting LANG=C ? I suspect there is a non-textual file, a multi-byte encoding, or a wrong encoding causing your problem. Before going any further, please check that. Cheers, Santiago
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