Bitcoin Forum

Hey there,

I have a question about syncing my bitcoin core. I didnt use it for a few weeks and had to update a few thousand blocks I did this yesterday with a rate of 4% per hour. I fully synced it now 24h later I opened it again to resync what happend in those 24h and now my rate is suddenly 0.01% and it takes forever to finihs the reamining blocks is that normal?

Blocks were generated in those 24 hours for which the client has to synchronize to catch up. From my experience, the synchronization when there are lesser blocks to catch up is much slower. It can be misleading as it often freezes the UI while synchronizing. It should be fine as long as you are able to wait for a bit.

My fairly powerful computer freezes as it starts to synchronize and only displays the initial rate which is usually fairly low (0.05%).

This isn't supposed to happen because the Qt window is supposed to be in a separate thread from the transaction verification thread, and there's only one verification thread only, unless the UI is sleep-waiting on the verification thread to finish (??) in which case it makes sense that it freezes because the verification thread is constantly waiting on disk I/O.

Your CPU usage while Bitcoin Core is freezing is fairly low, right? The other way it would make sense that it's freezing is when you're low on memory and Core "thrashes" the disk with more dbcache that it has to move between disk and RAM.

It happens: https://bitcointalk.org/index.php?topic=5315273.msg56287394#msg56287394.

I have limited my dbcache to 100MB before and it didn't help one bit. There is literally no way for the UI to be freezing due to resource constraints on my computer. Free ram usually hovers around 7GB or so and my NVMe isn't a bottleneck at all.

I think the problem is probably related to connecting to peers in order to obtain the blocks. The rate should improve as you connect to more peers.