Is it possible to have it work with a partial sync of a Bitcoin node?

[escapeneo]

I installed Bitcoin Core, and chose to sync my full node only up to block height 606,010 (when I reached that block height, I closed Bitcoin Core and inserted connect=0 into the Bitcoin config file) so I don't get any other blocks. I then turned Fulcrum and it started syncing those blocks; however, the process stopped and is now stuck for three full hours at this point:

[2025-01-27 00:32:47.810] <Controller> Processed height: 597000, 67.8%, 18.1 blocks/sec, 39260.4 txs/sec, 132972.5 addrs/sec [2025-01-27 00:33:18.850] <Controller> Storage UTXO Cache: Flushing to DB ... [2025-01-27 00:34:15.908] <Controller> Processed height: 598000, 67.9%, 11.4 blocks/sec, 25156.3 txs/sec, 81962.1 addrs/sec [2025-01-27 00:35:06.243] <Controller> Processed height: 599000, 68.0%, 19.9 blocks/sec, 42123.6 txs/sec, 135992.7 addrs/sec [2025-01-27 00:36:03.781] <Controller> Processed height: 600000, 68.1%, 17.4 blocks/sec, 38349.9 txs/sec, 121870.9 addrs/sec [2025-01-27 00:36:57.397] <Controller> Processed height: 601000, 68.2%, 18.7 blocks/sec, 39777.8 txs/sec, 129218.2 addrs/sec [2025-01-27 00:37:54.621] <Controller> Storage UTXO Cache: Flushing to DB ... [2025-01-27 00:38:37.348] <Controller> Processed height: 602000, 68.3%, 10.0 blocks/sec, 22926.7 txs/sec, 83349.5 addrs/sec [2025-01-27 00:39:38.076] <Controller> Processed height: 603000, 68.5%, 16.5 blocks/sec, 38090.8 txs/sec, 135135.3 addrs/sec [2025-01-27 00:40:41.513] <Controller> Processed height: 604000, 68.6%, 15.8 blocks/sec, 32782.2 txs/sec, 112028.9 addrs/sec [2025-01-27 00:41:55.611] <Controller> Processed height: 605000, 68.7%, 13.5 blocks/sec, 28639.8 txs/sec, 103371.4 addrs/sec [2025-01-27 00:42:51.127] <Controller> Processed height: 606000, 68.8%, 18.0 blocks/sec, 38790.7 txs/sec, 136442.5 addrs/sec [2025-01-27 00:42:51.637] <Controller> Processed 606011 new blocks with 479411650 txs (1178064770 inputs, 1278776241 outputs, 1810346733 addresses), verified ok. [2025-01-27 00:42:51.637] <Controller> Initial sync ended, flushing and deleting UTXO Cache ... [2025-01-27 00:42:51.637] <Controller> Storage UTXO Cache: Flushing to DB ...

Is there a way to use Fulcrum without having all the blocks? Block height 606,010 is enough for my use case, so I would appreciate if there's a way to make it possible to work with it, or if I need to make any adjustments?

[cculianu]

Yes there is -- you were almost there. It was flushing the UTXO cache but it seems to be taking a while to do that. I wonder why that is. You can try without the utxo-cache option... or tell me what utxo-cache size you used.

[escapeneo]

Yes there is -- you were almost there. It was flushing the UTXO cache but it seems to be taking a while to do that. I wonder why that is. You can try without the utxo-cache option... or tell me what utxo-cache size you used.

What made me think that it wasn't working, is I checked the process in the task manager, and it wasn't using anything in the disk or the processor, it just had a static RAM (memory) usage. Like if no I/O operations whatsoever were happening. Also, the very recent UTXO cache flushing (which was before the one that froze) took like a minute, that's why I doubted that it was working.

I had the issue both with default settings (without mentioning UTXO cache in the fulcrum.conf file) and also with UTXO_cache 4000 so I am not sure what may be wrong.

[escapeneo]

I have restarted the process again but with utxo_cache = 0. I also left my node (while Fulcrum was closed) to sync up to block height 650,543 and then I stopped it again with connect=0. After around 9-11 hours, it's stuck here:

[2025-01-28 05:20:07.502] <Controller> Processed height: 647000, 73.4%, 5.78 blocks/sec, 12677.3 txs/sec, 56857.9 addrs/sec [2025-01-28 05:22:45.779] <Controller> Processed height: 648000, 73.5%, 6.32 blocks/sec, 12950.7 txs/sec, 59231.9 addrs/sec [2025-01-28 05:25:16.626] <Controller> Processed height: 649000, 73.7%, 6.63 blocks/sec, 13106.6 txs/sec, 59100.7 addrs/sec [2025-01-28 05:27:57.033] <Controller> Processed height: 650000, 73.8%, 6.23 blocks/sec, 13441.1 txs/sec, 59500.2 addrs/sec [2025-01-28 05:29:20.571] <Controller> Processed 650544 new blocks with 572976592 txs (1411013606 inputs, 1523970373 outputs, 2185459747 addresses), verified ok.