I’m running a “backup” node in case something goes wrong with the main one I use.
However, on this backup node, which uses an external SSD and is less CPU-powerful than my main one, the mempool always appear empty.
I can see all the past blocks, I get the newly added blocks, but the “current mempool” or the “blocks to be mined” always appear empty (Attached image below).
There’s a warning in my mempool logs on the backup node which keeps repeating itself. This warning does not appear in the main node’s mempool logs (the one that works):
“2026-06-27T06:00:12+02:00 Jun 27 04:00:12 [2] INFO: Connected to Electrum Server at fulcrum.startos:50001 ([“Fulcrum 2.1.1”,“1.4”])
2026-06-27T06:06:15+02:00 Jun 27 04:06:15 [2] INFO: Core index ‘txindex’ is synced. Best block height is 955601
2026-06-27T06:06:15+02:00 Jun 27 04:06:15 [2] INFO: Core index ‘basic block filter index’ is synced. Best block height is 955601
2026-06-27T06:06:16+02:00 Jun 27 04:06:16 [2] INFO: migrated 0 audits to version 1
2026-06-27T06:06:16+02:00 Jun 27 04:06:16 [2] NOTICE: Migrating blocks to version 1 completed: migrated 0 blocks
2026-06-27T06:15:12+02:00 Jun 27 04:15:12 [2] INFO: Disconnected from Electrum Server at fulcrum.startos:50001
2026-06-27T06:15:13+02:00 Jun 27 04:15:13 [2] INFO: Connected to Electrum Server at fulcrum.startos:50001 ([“Fulcrum 2.1.1”,“1.4”])
2026-06-27T06:16:16+02:00 2026-06-27 4:16:16 5071 [Warning] Aborted connection 5071 to db: ‘mempool’ user: ‘mempool’ host: ‘127.0.0.1’ (Got timeout reading communication packets)“
Fulcrum logs do not show anything wrong, no warning or error.
Any idea what the problem could be ? I tried to rebuild mempool, but the problem did not disappear. It seems it keeps disconnecting from Fulcrum, and can’t access the db. How I could fix this ?
The two things you’re seeing aren’t actually one problem, and the database message is harmless.
The empty mempool itself comes from Bitcoin Core, not from Mempool. Mempool just shows you the unconfirmed transactions that your own Bitcoin node is currently holding. The Fulcrum/Electrum server you mentioned is only used for address searches — it has nothing to do with the list of pending transactions. So if Mempool looks empty, it’s because your backup node’s Bitcoin Core currently has an empty (or nearly empty) mempool.
Maybe:
It just finished syncing or was recently restarted. Bitcoin Core starts with an empty mempool and refills it from the network over time. Give it a few hours of uptime.
It has few peers, or a slow connection. Fewer peers means fewer pending transactions reach it. (You can check Bitcoin Core → it should have several connections.)
It’s running in a low-resource mode. If the node was set up with a very small mempool size limit, or in “blocks-only” mode, it intentionally won’t keep pending transactions. Worth double-checking the Bitcoin Core settings on the backup.
The slower CPU + external SSD simply make everything take longer to catch up after a restart — including the mempool refilling.
You would need to check your Bitcoin Core service and make sure it’s working.
So nothing’s broken with the database, and Mempool is most likely showing you exactly what your node currently has.
Hi, thanks for the answer. I get now that it comes from Bitcoin Knots and not the mempool itself.
After a long investigation and changes in my mempool settings (in Bitcoin Knots), I found the culprit: The dust relay fee I had set was way too high, so I reverted it back to default and now it works, I can see the transactions that are in the mempool.
