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Re: Benefits of asyncio

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Chris Angelico <rosuav@gmail.com>:

> Okay, but how do you handle two simultaneous requests going through
> the processing that you see above? You *MUST* separate them onto two
> transactions, otherwise one will commit half of the other's work. (Or
> are you forgetting Databasing 101 - a transaction should be a logical
> unit of work?) And since you can't, with most databases, have two
> transactions on one connection, that means you need a separate
> connection for each request. Given that the advantages of asyncio
> include the ability to scale to arbitrary numbers of connections, it's
> not really a good idea to then say "oh but you need that many
> concurrent database connections". Most systems can probably handle a
> few thousand threads without a problem, but a few million is going to
> cause major issues; but most databases start getting inefficient at a
> few thousand concurrent sessions.

I will do whatever I have to. Pooling transaction contexts
("connections") is probably necessary. Point is, no task should ever
block.

I deal with analogous situations all the time, in fact, I'm dealing with
one as we speak.

> Alright. I'm throwing down the gauntlet. Write me a purely nonblocking
> web site concept that can handle a million concurrent connections,
> where each one requires one query against the database, and one in a
> hundred of them require five queries which happen atomically. I can do
> it with a thread pool and blocking database queries, and by matching
> the thread pool size and the database concurrent connection limit, I
> can manage memory usage fairly easily; how do you do it efficiently
> with pure async I/O?

Sorry, I'm going to pass. That doesn't look like a 5-liner.


Marko

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Benefits of asyncio Aseem Bansal <asmbansal2@gmail.com> - 2014-06-02 10:40 -0700
  Re: Benefits of asyncio Ian Kelly <ian.g.kelly@gmail.com> - 2014-06-02 12:37 -0600
  Re: Benefits of asyncio Terry Reedy <tjreedy@udel.edu> - 2014-06-02 16:07 -0400
    Re: Benefits of asyncio Roy Smith <roy@panix.com> - 2014-06-02 16:19 -0400
    Re: Benefits of asyncio Marko Rauhamaa <marko@pacujo.net> - 2014-06-02 23:28 +0300
      Re: Benefits of asyncio Paul Rubin <no.email@nospam.invalid> - 2014-06-02 13:45 -0700
        Re: Benefits of asyncio Chris Angelico <rosuav@gmail.com> - 2014-06-03 07:49 +1000
        Re: Benefits of asyncio Terry Reedy <tjreedy@udel.edu> - 2014-06-02 21:51 -0400
        Re: Benefits of asyncio Marko Rauhamaa <marko@pacujo.net> - 2014-06-03 09:36 +0300
          Re: Benefits of asyncio Chris Angelico <rosuav@gmail.com> - 2014-06-03 18:47 +1000
            Re: Benefits of asyncio Marko Rauhamaa <marko@pacujo.net> - 2014-06-03 12:10 +0300
              Re: Benefits of asyncio Chris Angelico <rosuav@gmail.com> - 2014-06-03 19:30 +1000
                Re: Benefits of asyncio Marko Rauhamaa <marko@pacujo.net> - 2014-06-03 13:08 +0300
                Re: Benefits of asyncio Chris Angelico <rosuav@gmail.com> - 2014-06-03 20:23 +1000
                Re: Benefits of asyncio Marko Rauhamaa <marko@pacujo.net> - 2014-06-03 14:12 +0300
                Re: Benefits of asyncio Paul Rubin <no.email@nospam.invalid> - 2014-06-04 00:52 -0700
              Re: Benefits of asyncio Burak Arslan <burak.arslan@arskom.com.tr> - 2014-06-03 14:05 +0300
              Re: Benefits of asyncio Chris Angelico <rosuav@gmail.com> - 2014-06-03 21:57 +1000
              Re: Benefits of asyncio Burak Arslan <burak.arslan@arskom.com.tr> - 2014-06-04 08:10 +0300
              Re: Benefits of asyncio Chris Angelico <rosuav@gmail.com> - 2014-06-04 17:30 +1000
              Re: Benefits of asyncio Paul Rubin <no.email@nospam.invalid> - 2014-06-04 00:48 -0700
          Re: Benefits of asyncio "Frank Millman" <frank@chagford.com> - 2014-06-03 13:09 +0200
          Re: Benefits of asyncio Chris Angelico <rosuav@gmail.com> - 2014-06-03 22:01 +1000
            Re: Benefits of asyncio Marko Rauhamaa <marko@pacujo.net> - 2014-06-03 16:05 +0300
              Re: Benefits of asyncio Chris Angelico <rosuav@gmail.com> - 2014-06-03 23:31 +1000
                Re: Benefits of asyncio Marko Rauhamaa <marko@pacujo.net> - 2014-06-03 16:42 +0300
                Re: Benefits of asyncio Chris Angelico <rosuav@gmail.com> - 2014-06-03 23:49 +1000
                Re: Benefits of asyncio Marko Rauhamaa <marko@pacujo.net> - 2014-06-03 19:18 +0300
              Re: Benefits of asyncio Roy Smith <roy@panix.com> - 2014-06-03 11:40 -0400
        Re: Benefits of asyncio Paul Sokolovsky <pmiscml@gmail.com> - 2014-06-03 11:31 +0300
  Re: Benefits of asyncio Burak Arslan <burak.arslan@arskom.com.tr> - 2014-06-03 00:07 +0300
  Re: Benefits of asyncio Aseem Bansal <asmbansal2@gmail.com> - 2014-06-02 21:54 -0700

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