Re: [Pbwebgui-development] quick temperature check

[JT S. <jt...@pl...>]

The reason I can do this from an application environment is 2 fold.

1) The interval that the slaves use to update from the master is determined largely by 
the configuration of the slaves to their master.

2) As a developer, you control whether your app is reading directly from the master or 
from the slave, and presumably you know what your app needs to do to work properly.

 From a content viewing point of view, yes the data can be out of date for a little bit, 
but that's the whole purpose of caching in a content environment. Let the data go out of 
date for a little bit in order to not stress out the machine. If you're in an 
environment where cachable reads need to not be cached, then instead of buying 2 small 
database servers and doing replication, buy one motherhog database server and serve all 
requests from there.

I'm not trying to be a prick, shun anyone's ideas, or anything else dickheadish. It's 
just that:

1) This isn't an easy problem to solve in any way that doesn't cause other problems.

and

2) I don't think that the amount of time required to solve this particular problem is a 
good investment given that it's not even a problem yet.


On Sun, 11 Jul 2004 12:35:24 -0400
  "Jay R. Ashworth" <jr...@ba...> wrote:
>On Sat, Jul 10, 2004 at 11:05:51PM -0500, JT Smith wrote:
>> >I hate to sound like a pissant, but that doesn't help precisely the
>> >audience who care: those people who might, in fact, need to use it.
>> >
>> >So I guess the question is, how much impact will it have on them?
>> 
>> 
>> 1) I have no idea what you're even asking.
>> 
>> 2) You sound angry, and if you are, why?
>
>No, I wasn't.
>
>The issue, as I understand it, is this: if I have multiple WebGUI
>servers, running from replicated databases, one of which is defined as
>the 'master' instance, how do we handle reads of data which is --
>because we're in admin mode -- *required* to be current.
>
>My recommendation originally was to allow the read to be to whatever
>instance was local, and force a cache flush at that point. 
>
>You, if I understood you correctly (and vice versa), said that wasn't
>efficient enough, and that it was better to short circuit the read in
>the code directly to the master.
>
>Now, as I recap things, I wonder how you *could*, since they might be
>on different machines with no cross-connects, but perhaps I've
>misunderstood the issue completely.
>
>But in any event, if you *don't* force cache flushes (by which, in this
>case, I actually mean forcing an update between the replicated
>databases -- but from 30,000 feet, you can treat those replicated
>databases as a 'local cache', I think), then the slaves will be giving
>out bad data...
>
>and since your stated target for WebGUI is as an applications
>development environment -- notwithstanding that the only application
>being developed by a large part of it's userbase is "my website" :-) --
>then it seems to me that you can't just brush off the question he
>asked... which is what it seemed to *me* like you were doing.
>
>But I might be wrong.  :-)
>
>Cheers,
>-- jra
>-- 
>Jay R. Ashworth                                                jr...@ba...
>Designer                          Baylink                             RFC 2100
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>
>	"You know: I'm a fan of photosynthesis as much as the next guy,
>	but if God merely wanted us to smell the flowers, he wouldn't 
>	have invented a 3GHz microprocessor and a 3D graphics board."
>					-- Luke Girardi
>
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JT ~ Plain Black

Create like a god, command like a king, work like a slave.