I have currently set my Core node to -prune=550, but I see that getblocktemplate returns data, so can one mine on the pruned node?
Yes, you can mine.With only 550 blocks stored, how can/would a pruned node make sure that an input given by user to be signed in a block isn't a double spend? There'd be no way to check that on such a node, right?
(E: Although i think there's probably a mechanism for this, otherwise it wouldn't be able to verify any transactions at all.)
That's not how Bitcoin Core works. Pruned nodes are still full nodes. They have validated every block in the blockchain; they still validate and relay every single valid block and transaction they receive. They are, by definition, full nodes. The difference between pruning and not pruning is whether the node can serve historical blocks to new nodes coming online. Everything else is the same; they can be miners, they will still receive all blocks and transactions, etc. The UTXO data that is necessary for validation is not pulled from the block history, that would be rather slow. Instead, when a block is validated, the UTXOs are copied to a UTXO database and the UTXOs that were spent are removed from that database. Pruning still keeps that database and all of the UTXOs, so validation is still works.(E: Although i think there's probably a mechanism for this, otherwise it wouldn't be able to verify any transactions at all.)
Only Full Nodes for the 550 Blocks,
as you said, they do not allow blocks older than the 550 blocks.
Prune Nodes are Faux Nodes, for anything outside of the 550 block range.
The term they are full nodes is a falsehood propagated by core devs.
1. They don't allow any blocks beyond the 550 range to be downloaded.
2. If they were really full nodes then Tell Everyone to Prune and not waste their resources,
however you won't because that would damage the bitcoin network if their were no True Full Nodes which the pruned nodes are not.
Tell Everyone to Prune, I dare you.
FYI: https://news.bitcoin.com/pros-and-cons-on-bitcoin-block-pruning/
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Mining pool owners on the other hand may not want to adopt the block pruning option at all.
Granted, with 550 blocks of history, it should be possible to validate newly mined blocks on the network without too much trouble.
However, it might be in their best interest to keep the blockchain stored in its entirety as a failsafe as well.
With the recent issue surrounding invalid Bitcoin block validation, 550 blocks is not exactly a major buffer to prevent a potential Bitcoin fork.
And if the majority of mining pools end up on on a fork of the network for a lengthy period of time, all hell will break loose.
Granted, that issue affecting invalid block confirmations has been rectified in a swift manner,
but invalid blocks were being generated at an alarming rate for a lengthy period of time.
Granted, with 550 blocks of history, it should be possible to validate newly mined blocks on the network without too much trouble.
However, it might be in their best interest to keep the blockchain stored in its entirety as a failsafe as well.
With the recent issue surrounding invalid Bitcoin block validation, 550 blocks is not exactly a major buffer to prevent a potential Bitcoin fork.
And if the majority of mining pools end up on on a fork of the network for a lengthy period of time, all hell will break loose.
Granted, that issue affecting invalid block confirmations has been rectified in a swift manner,
but invalid blocks were being generated at an alarming rate for a lengthy period of time.