In order to reduce the size of the blockchain, we can use pruning with the bitcoin core client. The description of the option says:

Reduce storage requirements by pruning (deleting) old blocks. This mode disables wallet support and is incompatible with -txindex.

If I understand other sources explaining pruning, correctly, it will only keep unspent transaction outputs (UTXOs). This is what's stored in the LevelDB in the chainstate directory. Therefore, I would expect pruning to remove all other files (or rather all blk files) and only keep the chainstate DB. I cannot test this myself right now, hence my question. If someone uses the pruned mode, can you confirm that it uses around 2.5 GB (size of the chainstate)? Also, why does pruning disable the wallet support?

1 Answer 1


Pruning does not only keep the UTXO set. It also keeps the latest few hundred blocks, in order to assist with reorganizations.

Pruning was experimental in Bitcoin Core 0.11, and incompatible with the wallet. Since 0.12, it's a fully supported feature that works fine with the wallet.

  • So does pruning mean: keeping last N blocks, including necessarily all UTXOs, instead of entire blockchain?
    – croraf
    Oct 22, 2017 at 17:13
  • 2
    It means keeping (a) all UTXOs, from any time and (b) the last few blocks. Oct 22, 2017 at 17:54

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