Inconsistent min_gas_price value when in localnet/sandbox

[ChaoticTempest]

Describe the bug
On localnet or a sandbox node, gas estimations are 10x the amount. Seems this happening since min_gas_price is set to 1_000_000_000 instead of 100_000_000 which is what is found on mainnet/testnet. From my findings, BlockEconomicsConfig::min_gas_price determines the min_gas_price dynamically and lowers the min_gas_price to 100_000_000 for mainnet/testnet since their genesis protocol version is below a threshold. Meanwhile newly launched localnet or sandbox nodes have protocol version of 56 as of the time of writing this issue which doesn't meet the threshold and causes this inconsistency.

To Reproduce

• clone https://github.com/near/workspaces-rs/
• checkout branch phuong/test/proxy
• run cargo run --example proxy and then an error should occur like the following:

Error: handler error: [An error happened during transaction execution: InvalidAccessKeyError(NotEnoughAllowance { account_id: AccountId("dev-20220823224325-18831006822820"), public_key: ed25519:FzLCgiBnbhUvmcX78YWdugM7oapurcXcjAS4Fwt3hXi7, allowance: 56287890191155200000000, cost: 187424484981165931516950 })]

• to test for newer changes once changes are made to nearcore:
  • cd nearcore
  • make sandbox
  • cd workspaces-rs
  • NEAR_SANDBOX_BIN_PATH=/abolute/path/to/nearcore/sandbox/debug/neard cargo run --example proxy where the error no longer occurs

Version (please complete the following information):

• nearcore master
• local

Additional context
Initial conversation on it in zulip:
https://near.zulipchat.com/#narrow/stream/295558-pagoda.2Fcore/topic/Inconsistent.20min_gas_price.20on.20localnet.2Fsandbox/near/294942074

[akhi3030]

CC: @jakmeier. Is this something that you can help diagnose please?

[matklad]

Code in question:

nearcore/chain/chain/src/types.rs

Lines 172 to 192 in c0706b7

	/// Compute min gas price according to protocol version and genesis protocol version.
	pub fn min_gas_price(&self, protocol_version: ProtocolVersion) -> Balance {
	if self.genesis_protocol_version < MIN_PROTOCOL_VERSION_NEP_92 {
	if protocol_version >= MIN_PROTOCOL_VERSION_NEP_92_FIX {
	MIN_GAS_PRICE_NEP_92_FIX
	} else if protocol_version >= MIN_PROTOCOL_VERSION_NEP_92 {
	MIN_GAS_PRICE_NEP_92
	} else {
	self.min_gas_price
	}
	} else if self.genesis_protocol_version < MIN_PROTOCOL_VERSION_NEP_92_FIX {
	if protocol_version >= MIN_PROTOCOL_VERSION_NEP_92_FIX {
	MIN_GAS_PRICE_NEP_92_FIX
	} else {
	MIN_GAS_PRICE_NEP_92
	}
	} else {
	self.min_gas_price
	}
	}

I don't understand why genesis protocol version (as opposed to block's protocol version) would affect this in any way, this requires some git-blame archaeology.

[jakmeier]

I don't think the code listed above is relevant. That method seems to only be used to validate that any given block does not exceed limits, which does depend on current limits and genesis limits.

The problems seems to be here:

nearcore/nearcore/src/config.rs

Line 111 in cf71471

pub const MIN_GAS_PRICE: Balance = 1_000_000_000;

For some reason, this value has never been updated. It's also not used at all for mainnet, testnet, betanet or shardnet. Only if the chain id is something else, then the genesis config is generated and actually used. Otherwise this constant seems to be used for tests only.

I wonder if the solution is just to update the constant. It seems to break only one test (test_chunk_transaction_validity) from what I checked locally, which should be fixable. And it resolves the reported issue in sandbox. But I am not very happy about this constant being what it is right now. Feels like it should be cleaned up somehow but I am not deep in it yet to see what would be clean solution.

[jakmeier]

I think just increasing the constant really is the best way forward. The default gensis config should produce the gas price that is most recent. But I also added comments to make things easier to understand. See PR #7475.

I also noticed that shardnet has been launched with the old min_gas_price value, 10x the gas price used in mainnet/testnet/betanet. I don't think it matters in any way but probably not intentional. cc @mm-near @gmilescu

[mm-near]

Ah - that explains why some people have seen transactions costing over 30 NEAR ..

[jakmeier]

Well, 30 NEAR still sounds like a bit much for a single transaction, if it was only because of the 10x. But I also noticed in the explorer that gas price has been inflated to the max, making it another 20x more expensive. With that, 150Tgas indeed costs 3 NEAR. (But 30 NEAR should still be out of range?)

[jakmeier]

Oh, I just noticed that our pessimistic gas price charges go beyond the cap of 20x minimum price. Filed #7477. That explains why users needed more than 30 NEAR to initiate a transaction.