Except that criminologists haven't found any free and fair jurisdiction (with an independent judiciary) where the death penalty appears to be a deterrent for the majority of people committing crimes.  So how long they stay on death row in any one country isn't the reason for that.

The costs aren't unreal.  It costs more in every free and fair jurisdiction to have death row than it does to not have it.

I don't believe in murder.  I don't want the government murdering on my behalf.  Especially since a certain percentage of all convicted felons are actually innocent.  What percentage of innocent people will you accept dying in exchange for murdering the guilty ones?  1%  3%?  5%?  Most estimates I've seen of the number of actually innocent people on death row are in the 3-4% range.  There's no perfect system, if you are murdering the guilty you'll also be murdering the innocent to some degree.  So let's put a number on how many innocent you'd accept dying in exchange for the death of the guilty.  I'm genuinely curious on what acceptable collateral damage number you'd put on it.

If you are planning to rob a gas station and kill the teller for a few bucks knowing that you will be excuted if you do this, would you do it?  I would say that perenctage of committing the crime would go down if the death penalty is enforced. People would accept going to jail as long as they dont get excuted. It is logical and common sense. 

Don't have it in Australia.
Honestly, I'm not that into the idea of execution as punishment, only because I feel like death is easy. If there was somebody upon whom I wished the ultimate punishment, I would want them kept alive to experience it.
Once they're dead, they're just dead. Never to know your punishment ever again.

No and I am glad about that. It's expensive (for as for as I can believe last week tonight), irreversible and I would rather see a serial killer or pedophile suffer in a isolation cell than going out the easy way.

The lower the better, but there is no percent I'm good with, at the end of the day innoncent are murdered. But this morale argument is biased, as this problem is just ignored in most other cases. Did we renounced to war even if civilian casualties don't go lower than 25% of the total casualties ? Even if it's not that direct, when you allow people to buy cars, cigarets, guns, you know a given percent of innoncent people will die from it. Anyway, you are in favor of life sentence, but I don't ask you the percent of (non fixed) mistakes you accept, because it's not on you.

As for how high is the percent of innoncent, it's hard as the numbers are based on organizations against death sentence (I don't think the State itself claims to have 4%). I believe it could be extremely low if it was enforced to be necessary to have multiple direct proof (DNA, etc.), and if people involved were really accountable and faced strong charges in case they mishandled the case. Because every case of "mistakes" I've heard about were not that much mistakes than cops extorting confessions, sentence despite absence of tangible proves, and extremely carlessness. Have you ever heard any of them facing severe charge in a prosecution ?

About cost, I think I have a little idea of what you can have for 300 millions $. In software development, it's about 1000 people, full time, good wages, with diploma, massive hardware and facilities, for years. So is it really necessary or even really what you get for this cost ?

We don't have it, but in the constitution there is the possibility to use death penalty during a war as an emergencial measure.

It's a bit off-topic, but I think that it is interesting to say how Brazil stopped using death penalty. During the empire, we had death penalty (hanging). During D. Pedro II reign, a case became very notorious in the media: a rich farmer, Manuel da Mota Coqueiro, that was accused of the murder of his own wife and daughter. In that time, the only way to escape death penalty was through the pardon of the emperor so you could replace it with jail time. While he asked for it, the emperor denied the request and he was executed. Later, his innoncence was proved and that deeply disturbed the emperor.It was 1876.

While a few other people were executed after Manuel, the emperor soon started to give the pardon to everyone condemned to death. In 1889, the constitution created for the proclamation of the republic effectively abolished it.

It's not a perfect system, but there are crimes where it is perfectly clear what happened thanks to video evidence and high volumes of credible witnesses. Again, you seem to be of the mindset that the death penalty is used haphazardly. 

And apparently you don't read much, so I'll spell it out: For some criminals, death row is a waste of time and money. Hence the Texas law to speed that process up for clear-cut cases. It's a waste of time and money to hold onto them when they're going to die anyway. 

And if you think that modern day demons like Dalton Davis ( https://www.washingtonpost.com/news/morning-mix/wp/2016/08/18/man-sentenced-to-65-years-for-repeatedly-slamming-newborns-head-on-pavement-killing-her/ ) deserves anything less than death, then I think we're done talking.