Bitcoin core: Slow Progress on Syncing

Hey everyone, I've been trying to sync a node using bitcoin core, but I ran into a "core dumped" issue somewhere between blocks 750,000 and 800,000. I really don’t want to re-download everything. Now when I restart bitcoin-qt, it just shows me "replaying blocks: 0%". Here’s what I see in my debug logs: 2024-04-27T00:30:15Z LoadBlockIndexDB: last block file info: CBlockFileInfo(blocks=58, size=100189578, heights=803877...804359, time=2023-08-19...2023-08-22) 2024-04-27T00:30:15Z Checking all blk files are present... 2024-04-27T00:30:15Z Initializing chainstate Chainstate [ibd] @ height -1 (null) 2024-04-27T00:30:15Z Opening LevelDB in /media/myname/DD Externe/chainstate 2024-04-27T00:30:17Z Opened LevelDB successfully 2024-04-27T00:30:17Z Using obfuscation key for /media/myname/DD Externe/chainstate: 5f4cbf4f04be336c 2024-04-27T00:30:17Z Replaying blocks 2024-04-27T00:30:17Z Rolling forward 00000000000000000003448732b35cd9bb92eff0328bfc3e1800cd95d23721b8 (788897) 2024-04-27T00:31:59Z Rolling forward 000000000000000000001bff2639e28de97f48ec1497fda22bcfcf44ce196bede (788898) 2024-04-27T00:33:02Z Rolling forward 0000000000000000000560890080e8dc8c30196783035ff4adb1ab5dd979f8ee (788899) 2024-04-27T00:33:41Z Rolling forward 00000000000000000001e2993abf7288aed1671a3c5f6e3ecd09347aacd16595 (788900) 2024-04-27T00:37:03Z Rolling forward 00000000000000000002731186762fba5cde45adc550f0308c9790f9d768dcad (788901) 2024-04-27T00:39:35Z Rolling forward 00000000000000000001e9818fd9be9145fd07bd60f44dc8d13fd466cb27c103 (788902) 2024-04-27T00:41:25Z Rolling forward 000000000000000000026ea74cd2b8fadebf4d5d4ee65186902490455d7bf706 (

This happens when restarting when  the database flush was interrupted by an unexpected shutdown. It has to start with what was in the database, and re-apply all of the state changes represented by the blocks on disk. This is a very disk I/O intensive process, so if your disk is slow, it will take a while. It looks like you are using an external disk, so there may be a slowdown caused by USB and/or the physical connection itself. Considering that it is doing a subset of the things done during block download, it seems likely that if you tried to redownload the blockchain, it would take just as long to download it. It's also not possible to download from a specific block height unless you delete some of the block files, but that would also trigger a reindex.

Let me guess... is the OP using Windows? I gave up on running node on Windows, it causes problems, it's preferable to run Bitcoin Core on a Linux distro (I use Ubuntu), OP can create a partition to use as a dualboot with Windows, without having to delete Windows. On Windows, especially if you have a desktop and the power shut down suddenly while the node is running, it's rare that there are no problems and you have to reindex or re-download all the blocks.

I had my own issues recently, but it's not unexpected since I had my data on an external HDD. I ended up re-downloading everything and, with an old trick it went fast and painlessly (although on Windows, heh) : I've moved to my (rather small) SSD 3 folders (block\index, chainstate, indexes\txindex) and creaded symbolic links to them.

Facing this issue of "Rolling forward.." since a restart of my system. NOT ON WINDOWS!! Very painful. I just calculated and at the current speed,  it is going to take me 80+ hours just to catch up provided no new blocks are found on the network I have been kicked back to 14th May 2024, not sure how because I had restarted my system many times after that. What sucks is that this time I did run 'bitcoin-cli stop' and forgot about that terminal expecting it to complete the process, but it didn't. It is really sad that BTCD has still not fixed this issue.