What happens if the log index number reaches the maximum variable value?

[Ivan Pim]

Hello,

Sorry if my question is not relevant.

But I have a question on log index/log compaction when using the Raft algorithm.

The Raft paper says that when we make a snapshot to compact the logs, we keep the following info in the snapshot:

• Last included index (which is just a sequential number of all committed commands to the state machine)
• Last included term
• And the state machine data

My question is (I know it's more theoretical) - what if the last included index (log index) exceeds the max integer size (e.g. 18446744073709551615 for uint64 type)?

I guess there should be some mechanism to reset the last included index in a practical implementation.

Same goes for the last included term but reaching such a limit sounds highly improbable.

Thank you!

[Oren Eini (Ayende Rahien)]

You are sending 1 million events per second.

At this rate, it will take you 584,942 years to run out.

You can probably ignore this issue.

Hibernating Rhinos Ltd  

Oren Eini l CEO l Mobile: + 972-52-548-6969

Office: +972-4-622-7811 l Fax: +972-153-4-622-7811

 

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[Henrik Ingo]

Hi Ivan

As Oren pointed out, you probably shouldn't worry about this. BUT I
wanted to point out that an equivalent choice would be to use
term+index as the index, where the index part would reset to zero
after each new term.

henrik

On Mon, May 7, 2018 at 3:38 PM, Ivan Pim <ivan.pim...@gmail.com> wrote:

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