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| Date | Wed, 25 Feb 2015 17:07:35 +1100 |
| Subject | Re: Are threads bad? - was: Future of Pypy? |
| From | Chris Angelico <rosuav@gmail.com> |
| Cc | Python <python-list@python.org> |
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On Wed, Feb 25, 2015 at 5:02 PM, Ian Kelly <ian.g.kelly@gmail.com> wrote: >> Uhh, I have seen *heaps* of code whose performance suffers from too >> much locking. At the coarsest and least intelligent level, a database >> program that couldn't handle concurrency at all, so I wrote an >> application-level semaphore that stopped two people from running it at >> once. You want to use that program? Ask the other guy to close it. >> THAT is a performance problem. And there are plenty of narrower cases, >> where it ends up being a transactions-per-second throughput limiter. > > Is the name of that database program "Microsoft Access" perchance? No, though it wouldn't surprise me if it had the same issue. No, the program was a DBase-backed one of my own development; it was the DBase engine itself that couldn't handle concurrency, so I added some startup code that checked to see if anyone else had the file open, and popped up a "retry or cancel" prompt until the semaphore cleared. Later on, I was able to shift the entire content into DB2 (once we no longer needed compatibility with an even older DBase-backed program), and voila, we had concurrency. I still needed to make use of record-level locking (if you open a record for editing, it holds a lock for as long as you have the window open; chances are, anyone else who wants the same record is actually doing the same job, so erroring out is the best option), but no more database-level locks. ChrisA
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Future of Pypy? Dave Farrance <DaveFarrance@OMiTTHiSyahooANDTHiS.co.uk> - 2015-02-22 12:45 +0000
Re: Future of Pypy? jkn <jkn_gg@nicorp.f9.co.uk> - 2015-02-22 04:58 -0800
Re: Future of Pypy? Dave Farrance <DaveFarrance@OMiTTHiSyahooANDTHiS.co.uk> - 2015-02-22 15:30 +0000
[OT] - BASIC is still not a bad choice, was Re: Future of Pypy? Michael Torrie <torriem@gmail.com> - 2015-02-23 17:24 -0700
Re: Future of Pypy? Laura Creighton <lac@openend.se> - 2015-02-22 14:27 +0100
Re: Future of Pypy? Dave Farrance <DaveFarrance@OMiTTHiSyahooANDTHiS.co.uk> - 2015-02-22 15:36 +0000
Re: Future of Pypy? Laura Creighton <lac@openend.se> - 2015-02-22 18:22 +0100
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-22 11:02 -0800
Re: Future of Pypy? Laura Creighton <lac@openend.se> - 2015-02-22 20:51 +0100
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-22 12:14 -0800
Re: Future of Pypy? Laura Creighton <lac@openend.se> - 2015-02-22 23:13 +0100
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-22 18:45 -0800
Re: Future of Pypy? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-23 12:18 +1100
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-22 18:04 -0800
Re: Future of Pypy? Chris Angelico <rosuav@gmail.com> - 2015-02-23 13:16 +1100
Re: Future of Pypy? Ryan Stuart <ryan.stuart.85@gmail.com> - 2015-02-23 03:16 +0000
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-22 19:45 -0800
Re: Future of Pypy? Ryan Stuart <ryan.stuart.85@gmail.com> - 2015-02-23 04:00 +0000
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-22 22:13 -0800
Re: Future of Pypy? Ryan Stuart <ryan.stuart.85@gmail.com> - 2015-02-23 07:32 +0000
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-23 16:11 -0800
Re: Future of Pypy? Chris Angelico <rosuav@gmail.com> - 2015-02-24 11:31 +1100
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-23 17:50 -0800
Re: Future of Pypy? Chris Angelico <rosuav@gmail.com> - 2015-02-24 13:03 +1100
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-23 20:40 -0800
Re: Future of Pypy? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-24 17:57 +1100
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-27 13:40 -0800
Re: Future of Pypy? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-02-27 18:47 -0500
Are threads bad? - was: Future of Pypy? Ryan Stuart <ryan.stuart.85@gmail.com> - 2015-02-24 00:35 +0000
Re: Are threads bad? - was: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-23 21:27 -0800
Re: Are threads bad? - was: Future of Pypy? Chris Angelico <rosuav@gmail.com> - 2015-02-24 16:57 +1100
Re: Are threads bad? - was: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-23 22:23 -0800
Re: Are threads bad? - was: Future of Pypy? Marko Rauhamaa <marko@pacujo.net> - 2015-02-24 10:08 +0200
Re: Are threads bad? - was: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-24 15:53 -0800
Re: Are threads bad? - was: Future of Pypy? Marko Rauhamaa <marko@pacujo.net> - 2015-02-25 07:25 +0200
Re: Are threads bad? - was: Future of Pypy? Marcos Almeida Azevedo <marcos.al.azevedo@gmail.com> - 2015-02-25 13:34 +0800
Re: Are threads bad? - was: Future of Pypy? Marko Rauhamaa <marko@pacujo.net> - 2015-02-25 07:46 +0200
Re: Are threads bad? - was: Future of Pypy? Chris Angelico <rosuav@gmail.com> - 2015-02-25 16:54 +1100
Re: Are threads bad? - was: Future of Pypy? Marcos Almeida Azevedo <marcos.al.azevedo@gmail.com> - 2015-02-25 13:58 +0800
Re: Are threads bad? - was: Future of Pypy? Ian Kelly <ian.g.kelly@gmail.com> - 2015-02-24 23:02 -0700
Re: Are threads bad? - was: Future of Pypy? Chris Angelico <rosuav@gmail.com> - 2015-02-25 17:07 +1100
Re: Are threads bad? - was: Future of Pypy? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-02-25 16:37 +0000
Re: Are threads bad? - was: Future of Pypy? Ian Kelly <ian.g.kelly@gmail.com> - 2015-02-25 10:00 -0700
Re: Are threads bad? - was: Future of Pypy? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-02-25 17:16 +0000
Re: Are threads bad? - was: Future of Pypy? Chris Angelico <rosuav@gmail.com> - 2015-02-26 04:22 +1100
Re: Are threads bad? - was: Future of Pypy? Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-02-25 19:44 -0500
Re: Are threads bad? - was: Future of Pypy? Ryan Stuart <ryan.stuart.85@gmail.com> - 2015-02-25 00:59 +0000
Re: Are threads bad? - was: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-26 21:55 -0800
Re: Future of Pypy? Chris Angelico <rosuav@gmail.com> - 2015-02-23 14:25 +1100
Re: Future of Pypy? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-23 18:41 +1100
Re: Future of Pypy? Marko Rauhamaa <marko@pacujo.net> - 2015-02-23 10:16 +0200
Re: Future of Pypy? Chris Angelico <rosuav@gmail.com> - 2015-02-23 20:19 +1100
Re: Future of Pypy? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-24 17:56 +1100
Re: Future of Pypy? Chris Angelico <rosuav@gmail.com> - 2015-02-24 18:16 +1100
Re: Future of Pypy? wxjmfauth@gmail.com - 2015-02-23 23:57 -0800
Re: Future of Pypy? Ethan Furman <ethan@stoneleaf.us> - 2015-02-23 11:39 -0800
Re: Future of Pypy? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-24 13:15 +1100
Re: Future of Pypy? Paul Rubin <no.email@nospam.invalid> - 2015-02-23 17:47 -0800
Re: Future of Pypy? Marko Rauhamaa <marko@pacujo.net> - 2015-02-24 10:12 +0200
Re: Future of Pypy? Emile van Sebille <emile@fenx.com> - 2015-02-24 09:57 -0800
Re: Future of Pypy? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-23 01:05 +1100
Re: Future of Pypy? Dave Farrance <DaveFarrance@OMiTTHiSyahooANDTHiS.co.uk> - 2015-02-22 15:44 +0000
Re: Future of Pypy? Dave Farrance <DaveFarrance@OMiTTHiSyahooANDTHiS.co.uk> - 2015-02-22 19:20 +0000
Re: Future of Pypy? Laura Creighton <lac@openend.se> - 2015-02-22 22:45 +0100
Re: Future of Pypy? Dave Farrance <DaveFarrance@OMiTTHiSyahooANDTHiS.co.uk> - 2015-02-23 14:04 +0000
Re: Future of Pypy? Laura Creighton <lac@openend.se> - 2015-02-23 17:16 +0100
Re: Future of Pypy? Terry Reedy <tjreedy@udel.edu> - 2015-02-23 01:34 -0500
Re: Future of Pypy? Dave Cook <davecook@nowhere.net> - 2015-02-23 11:36 +0000
Re: Future of Pypy? Dave Farrance <DaveFarrance@OMiTTHiSyahooANDTHiS.co.uk> - 2015-02-23 14:13 +0000
Cython - was: Future of Pypy? Stefan Behnel <stefan_ml@behnel.de> - 2015-02-23 16:43 +0100
Re: Future of Pypy? Dave Cook <davecook@nowhere.net> - 2015-02-23 23:23 +0000
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