Super-sized Epoch

[Josh]

This may be a dumb question, but what happens when the current epoch reaches a value of 9223372036854775807, the largest value that Vertica can store in an INT field?

I'm getting awfully close:

Code: Select all

dbadmin=> select get_current_epoch();
 get_current_epoch 
--------------------------------
             9012381236543125234
(1 row)

[NorbertKrupa]

I suppose that since it's a signed integer, it could over flow into a negative integer. I would guess there would be a mechanism that would start it back at zero though. I'm curious as to how it actually works though and whether your cluster blows up.

[scutter]

That’s one heck of a large number of epochs. How did it get to be so high? I think the theory in engineering is that you would never run out of epoch numbers. I wouldn’t assume that something benign will happen if you get there. Is your epoch rate really increasing at a rate that you’d reach the limit? If yes…what are you doing with that cluster

—sharon

[Josh]

Hi,

I was just kidding about the size of my current epoch (I edited the output) I just wanted to see if someone was actually reading my posts. But on a serious note, I am very curious if anyone knows what would happen if we actually reach the epoch size limit that we're never supposed to be able to reach! Never had that before... (Everyone forgets Y2K).

Thanks for responding!

[JimKnicely]

This is what will happen to your host server when your epoch reaches 9223372036854775808:

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  OUCH.png (147.21 KiB) Viewed 12333 times

[NorbertKrupa]

According to my trainer, even if the epoch is refreshed a few times per second, it would take some 18,000 years before it overflows/explodes

[Josh]

it would take some 18,000 years before it overflows/explodes

Ok, I feel a lot safer now as I won't be around then