_Originally posted by @S3RK in https://github.com/bitcoin/bitcoin/pull/24984#pullrequestreview-952900468_

> With current implementation we don't save the rescan progress and on the next load we will have to start from scratch. Is it possible to save the last processed blocked at shutdown?

It would be nice if wallet code would call `WriteBestBlock` and save the last scan position if it is interrupted during a sync. This could be implemented by trying to save the scan position during the shutdown, or by just periodically saving the scan position after an interval, similar to indexing code which saves sync position once every 30 seconds:

https://github.com/bitcoin/bitcoin/blob/f0a834e2f10a0aa60c7cc76e9f3eb090168a32e5/src/index/base.cpp#L170-L175
void UnsetBlankWalletFlag(WalletBatch& batch) override;
    
    const ArgsManager& m_args;
    
    interfaces::Chain* m_chain;
    
    std::string m_name;
    
    std::unique_ptr<WalletDatabase> const m_database;
    /**
     * The following is used to keep track of how far behind the wallet is
     * from the chain sync, and to allow clients to block on us being caught up.
     *
     * Processed hash is a pointer on node's tip and doesn't imply that the wallet
     * has scanned sequentially all blocks up to this one.
     */
    uint256 m_last_block_processed GUARDED_BY(cs_wallet);
    /** Height of last block processed is used by wallet to know depth of transactions
     * without relying on Chain interface beyond asynchronous updates. For safety, we
     * initialize it to -1. Height is a pointer on node's tip and doesn't imply
     * that the wallet has scanned sequentially all blocks up to this one.
     */
    int m_last_block_processed_height GUARDED_BY(cs_wallet) = -1;
    std::map<OutputType, ScriptPubKeyMan*> m_external_spk_managers;
    std::map<OutputType, ScriptPubKeyMan*> m_internal_spk_managers;
    
    
    std::map<uint256, std::unique_ptr<ScriptPubKeyMan>> m_spk_managers;
    /**
     * Catch wallet up to current chain, scanning new blocks, updating the best