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Message from discussion increment() creates new keys.
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gf pro  
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 More options Jul 17 2009, 4:32 am
From: gf pro <kak.serpom.po.yait...@gmail.com>
Date: Fri, 17 Jul 2009 12:32:05 +0400
Local: Fri, Jul 17 2009 4:32 am
Subject: Re: increment() creates new keys.
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while (!redis.INCR(foo)) {redis.SETNX(foo,1);}

2009/7/17 Ian Holsman <kry...@gmail.com>

> gf wrote:
> > Just SETNX ;-)

> similar issues.
> you end up with this.

> if (!redis.INCR(foo) {
>    if ( !redis.SETNX(foo,1) ) {
>       redis.INCR(foo)
>    }
> }
> as 2 people could be incrementing the counter (and failing) at the same
> time, and trying to set it to 1 at the same time (with 1 failing).
> fugly.
> > On 16 июл, 04:32, Ian Holsman <kry...@gmail.com> wrote:

> >> gf wrote:

> >>> Hello.
> >>> "INCR notexists" returns 1, but I think it has to return "false".

> >> but if you do that the code around incrementing it would look quite
> >> fugly no?

> >> cnt = redis.INCR("foo");
> >> if ( cnt is boolean && cnt == false ) {
> >>     redis.SET("foo",1);

> >> }

> >> ?
> >> this also leads to the problem of thread races where multiple people are
> >> executing the same logic. you might have n threads/clients running
> >> through this code at the same time.
> >> and you would end up with 'foo' being 1. instead of n.
> >> so your logic would then need to be something like

> >> redis.lock("foo")
> >> cnt = redis.INCR("foo");
> >> if ( cnt is boolean && cnt == false ) {
> >>     redis.SET("foo",1);}

> >> redis.unlock("foo")


 
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