Bitcoin Forum

    "errors" : "WARNING: abnormally high number of blocks generated, 48 blocks received in the last 4 hours (24 expected)" 

Discussion thread for this new warning.

What this means:

48 blocks were found within the last 4 hours. The average is "supposed" to be 1 block every 10 minutes, or 24 blocks over a 4 hour window. Normally, however, blocks are found at random intervals, and quite often faster than every 10 minutes due to miners continually upgrading or expanding their hardware. In this case, the average has reached as low as 5 minutes per block, which triggers the warning.
If the network hashrate was not increasing, this event should occur only once every 50 years. To happen on average, persistently, the network would need to double its hashrate within 1 week, and even then the warning would only last part of that 1 week. So this is a pretty strange thing to happen when Bitcoin is only 6 years old - but not impossible either.

Why is this a warning?

It's possible that a new mining chip has just been put online that can hash much faster than the rest of the network, and that miner is now near-doubling the network hashrate or worse. They could have over 51%, and might be performing an attack we can't know about yet. So you may wish to wait for more blocks than usual before considering high-value transactions confirmed, but unless this short block average continues on for another few hours, this risk seems unlikely IMO.

Has the blockchain forked?

No, this warning does not indicate that.

Will the warning go away on its own?

Bitcoin Core will continue re-issuing the warning every day until the condition (>=2x more blocks) ceases. When it stops issuing the warning, however, the message will remain in the status bar (or RPC "errors") until the node is restarted.

Is this related to some block explorer website showing the same blocks twice?

No, as far as I can tell that is an unrelated website bug.

i have reload my node and everything is back to normal. Is the first time that this happens?

what is this warning meaning for bitcoin? Is there something unusual happen?

We know the hashrate is increasing, maybe up to 10%, so this mean this event can happen more often than once every 50 years just by chance. But even once in 25 years is lucky event indeed.

Normally the farms add signifficant hashing power over longer window than 4 hours, it seems pretty impossible someone double the network hashrate by installing all the ten thousands of units and then just power it all up  ::)

lets hope it will not impact the price to go down because of that

this is like saying, "we had an average of 1 block every 5 minutes for the past 4 day", double of the luck, would have been an issue in case it was every 1-2 minutes maybe...

as i see it it can happen, like it happened in the past that for two hours there were no blocks

this is like saying, "we had an average of 1 block every 5 minutes for the past 4 day", double of the luck, would have been an issue in case it was every 1-2 minutes maybe...

as i see it it can happen, like it happened in the past that for two hours there were no blocks

If anything this statistical anomaly is a good thing, since people will get their transactions confirmed faster while also helping to clear out the backlog in the mempool. :)

4 hours not days..

i think luke_Jr had an itchy trigger finger and wanted to test out the bitcoin alert system.. even he, as a pool owner and developer should know that the difficulty doesnt change for 2 weeks.. so if a new miner has come on the scene or an existing miner has upped their hashing power, the difficult wont compensate for many days..

and the chances of a miner upping their hashrate is not once in 50 years... its an every day risk..
where did luke_jr even get that 50year statistical calculation from??

If the network hashrate was not increasing, this event should occur only once every 50 years

And the unconfirmed transactions drops under 2k  :o

looking at the last 4 difficulty change dates which should be 14 days apart (2016 blocks /144 blocks a day)

Dec 18 2015    18.14%    668,931,642 GH/s
Dec 06 2015    8.77%    566,236,898 GH/s
Nov 24 2015    10.44%    520,569,941 GH/s
Nov 11 2015    5.77%    471,360,171 GH/s

Bitcoin Difficulty:   93,448,670,796
Estimated Next Difficulty:   105,042,722,011 (+12.41%)
Adjust time:   After 570 Blocks, About 3.5 days
Hashrate(?):   846,369,830 GH/s :D

Ok, so, reading through this thread, theere doesnt seem to be much of a consensus here on what is causing this. Some seem to believe it's a new farm/chip being tested, while others say its simply an expected anomoly.

Both, seem to make sense, or at least be theoretically true.... so which is it?

yes seems normal  for now considering how much posts over the years for

block delays

4 hours not days..

i think luke_Jr had an itchy trigger finger and wanted to test out the bitcoin alert system.. even he, as a pool owner and developer should know that the difficulty doesnt change for 2 weeks.. so if a new miner has come on the scene or an existing miner has upped their hashing power, the difficult wont compensate for many days..

and the chances of a miner upping their hashrate is not once in 50 years... its an every day risk..
where did luke_jr even get that 50year statistical calculation from??