Transaction priority

In Subtensor, transaction priority is determined by custom transaction extensions, which alter or override the default Substrate SDK behavior. Extensions affecting transaction priority are:

• ChargeTransactionPaymentWrapper (wraps ChargeTransactionPayment)
• DrandPriority

Substrate SDK combines priorities from all transaction extensions using addition.

ChargeTransactionPaymentWrapper

In the Substrate SDK, ChargeTransactionPayment normally calculates transaction priority based on:

• Tip — an extra fee paid by the sender.
• Weight — computational complexity of the transaction.
• Dispatch class — category of the transaction (Normal, Operational, Mandatory).

However, in Subtensor, ChargeTransactionPaymentWrapper overrides this logic. It replaces the dynamic calculation with a flat priority scale based only on the dispatch class.

Current priority values

Dispatch Class	Priority Value	Notes
Normal	1	Standard transactions
Mandatory	1	Rarely used, same as Normal
Operational	10_000_000_000	Reserved for critical system extrinsics (e.g.: sudo calls)

DrandPriority

Special pallet_drand priority: 10_000 for write_pulse extrinsic.