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Postings from March 2002
On Tue, Mar 19, 2002 at 11:16:40PM -0500, Uri Guttman wrote: > > this current thread on fwp on perl saving someone's job is interesting > and i think more on the lines of advocacy and even discussing perl > jobs. so i cc'ed to those lists to get more of those 'perl saved my A**' > stories. we have success stories on jobs.perl.org and others on > perl.com. and advocacy has some stories i think. but a collection of > these stories would be great to have. HOW PERL SAVED MY A** Background: I used to be development/1st-/2nd-/3rd-line tech. support for a software house selling back-office systems to lawyers. Lawyers accounts remain open for the life of a case -- you can't transfer balances at the end of a period like (some) normal accounts. Therefore you have to transfer data from any existing system -- even if it's a 20 year-old mini from a defunct manufacturer, with no support, no documentation, no system software and no file/record layouts. We would get the user to print all the reports on the system ... and capture the output to disk. I used grep+sed+awk to process these text files into the form our application needed. The story: Close of business one Friday afternoon: I visited a firm of lawyers and collected their live data. I took the data home and started the conversion on the machine that I would be installing -- with the converted data -- on Monday morning. (I had already collected test data and written and tested the scripts with a sub-set of the data). The conversion should take until Saturday night, then I would spend Sunday verifying and cross-checking the results. Saturday morning: come down to find the machine only 10% through the processing and the disk chattering away. I eventually managed to log in and found that the awk conversion process was using all RAM + 50% swap ... and growing at 4kB every few records ... A quick calculation showed that (a) it would run out of swap before completion and (b) it was not going to be finished in time for a Monday morning installation. ARRRRRGH! I was committed to a Monday install. One thing you learn working for lawyers -- you do not upset lawyers: it tends to be expensive. Aside: I had been playing round with this new language that has been released (in several dozen messages posted to comp.lang.misc (or something)): Perl -- already at version 3. I had managed to get it compiled on the Altos Unix systems we were using then, but hadn't done much with it -- the challenge had been getting it running on Altos Unix :-), but I'd noticed that (a) it was supposed to be at least 10x faster than awk and (b) it had a awk-to-perl translator. I happened to have a tape with Perl compiled for Altos Unix with me. Back to the plot: * I cut several thousand lines of awk code out of the shell scripts they were embedded in and saved them in separate files. * I installed perl from the tape. * I ran a2p on the files -- and saved the results. I noticed a few warnings telling me to check whether the correct character or numeric test had been chosen: it had. * a2p also pointed out a mis-placed comment -- that turned out to be causing the memory leak -- but didn't generate an error or warning from awk. Even though removing the comment had (apparently) solved to problem, I was running late, so having created the Perl scripts I decided to use them: the processing took under 1 hour. ** The processing took under 1 hour. ** The expected processing time in awk was ~18 hours: In spite of the problems with awk, because of Perl I was now ahead of schedule. The system was installed on the Monday morning. This story still brings tears of relief/joy to my eyes. I have used Perl ever since. -- Chris Benson