First note is that Strptime is designed to be flexible. Speed wasn't the goal. That said, it also wasn't designed to be slow!
Second, and most importantly, your benchmark should fare MUCH better if you don't create a new parser every time. Create the parser outside the benchmark sub and it should be muuuuuuch quicker. And that is how your production code should work. - Rick 📱 > On 31 Jan 2014, at 5:58, Marcin Kasperski <marcin.kasper...@mekk.waw.pl> > wrote: > > > I was optimizing some log-parsing script today, and found > DateTime::Format::Strptime to be bottleneck. Out of curiosity I wrote > simple benchmark. Code is here: > http://pastebin.com/PU8nXGPW > > Results are interesting, as they show fairly noticeable differences: > http://pastebin.com/S4rt6bYd > (run on Ubuntu 12.04 with perl 5.14.2 and ubuntu-packaged datetime > modules) > > While the fact that „trying many approaches” parses like Natural or > Flexible are slow is, well, natural (still DateParse is much better), > I find it confusing that Strptime is soo slow. ISO8601 parser also > has fairly strict syntax to handle so I expected it to perform better... > > Any insights? And which parsing method would you recommend to get > optimal performance? > > ~~~~ Sidenote ~~~~~ > > DateTime::Format::Builder does not give any easy way to treat > „below-second” part with float semantic (treat .12 as 120 miliseconds, > treat .1347 as 134700 microseconds, etc). In spite of the fact, that > this is most natural and ... only sensible semantics. > > As you can see from my code and it's results, DateTime::Format::Flexible > falls into this trap (treats those digits as nanoseconds even if there > are less than 9 of them), while my hand-made builders require > postprocessing to clean this field up. > > Am I missing sth? Is there a way to handle this better? > -- > Message protected for iSite by MailGuard: e-mail anti-virus, anti-spam and > content filtering.http://www.mailguard.com.au > Click here to report this message as spam: > https://login.mailguard.com.au/report/1ITnAf1Ld9/7AiiWUInKq0y5APy9tARIw/0 > -- Message protected for iSite by MailGuard: e-mail anti-virus, anti-spam and content filtering.http://www.mailguard.com.au
