The size of each block is one trillion, which can hold more than one thousand transactions. If you go to a bitcoin blockchain browser, you will find that each block is about one trillion now, which has reached the upper limit of block capacity. If there are more and more transfers in the bitcoin network, many transactions will not be packaged and confirmed in the first block after the transaction. You may have to wait a few blocks or more. In the history of Bitcoin, there have been several sandstorms, among which many traders made a large number of small transfers on the exchange (currency exchange). Dust attack is that someone has made a large number of small transfers, which makes a large number of transactions in the network to be confirmed, which leads to the failure to confirm the normal transfer, and the confirmation time is delayed, which affects the normal operation of the network.

Many traders have to wait two days or more to confirm their trades. Although the dust attack is a very extreme example, at present, the normal transfer amount of Bitcoin network has far exceeded the maximum capacity it can bear. Now the size of each block is one trillion, so expanding the capacity of bitcoin blocks and breaking through the existing limit of one trillion is called capacity expansion.