chore: update default mempool walk strategy

I think we have mined long enough with this setting to be confident to
make it the default in the next release.

Author: obycode

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to the versioning scheme outlined in the [README.md](RE
 - Reduce the default `block_rejection_timeout_steps` configuration so that miners will retry faster when blocks fail to reach 70% approved or 30% rejected.
 - Added index for `next_ready_nakamoto_block()` which improves block processing performance.
 - Added a new field, `parent_burn_block_hash`, to the payload that is included in the `/new_burn_block` event observer payload.
+- Changed default mempool walk strategy to `NextNonceWithHighestFeeRate`
 
 ## [3.1.0.0.8]
 

stackslib/src/config/mod.rs

@@ -2224,7 +2224,7 @@ impl Default for MinerConfig {
             activated_vrf_key_path: None,
             fast_rampup: false,
             underperform_stop_threshold: None,
-            mempool_walk_strategy: MemPoolWalkStrategy::GlobalFeeRate,
+            mempool_walk_strategy: MemPoolWalkStrategy::NextNonceWithHighestFeeRate,
             txs_to_consider: MemPoolWalkTxTypes::all(),
             filter_origins: HashSet::new(),
             max_reorg_depth: 3,
@@ -2758,7 +2758,7 @@ impl MinerConfigFile {
             underperform_stop_threshold: self.underperform_stop_threshold,
             mempool_walk_strategy: self.mempool_walk_strategy
                 .map(|s| str::parse(&s).unwrap_or_else(|e| panic!("Could not parse '{s}': {e}")))
-                .unwrap_or(MemPoolWalkStrategy::GlobalFeeRate),
+                .unwrap_or(MemPoolWalkStrategy::NextNonceWithHighestFeeRate),
             txs_to_consider: {
                 if let Some(txs_to_consider) = &self.txs_to_consider {
                     txs_to_consider

stackslib/src/core/mempool.rs

@@ -575,7 +575,7 @@ pub struct MemPoolWalkSettings {
 impl Default for MemPoolWalkSettings {
     fn default() -> Self {
         MemPoolWalkSettings {
-            strategy: MemPoolWalkStrategy::GlobalFeeRate,
+            strategy: MemPoolWalkStrategy::NextNonceWithHighestFeeRate,
             max_walk_time_ms: u64::MAX,
             consider_no_estimate_tx_prob: 5,
             nonce_cache_size: 1024 * 1024,
@@ -589,7 +589,7 @@ impl Default for MemPoolWalkSettings {
 impl MemPoolWalkSettings {
     pub fn zero() -> MemPoolWalkSettings {
         MemPoolWalkSettings {
-            strategy: MemPoolWalkStrategy::GlobalFeeRate,
+            strategy: MemPoolWalkStrategy::NextNonceWithHighestFeeRate,
             max_walk_time_ms: u64::MAX,
             consider_no_estimate_tx_prob: 5,
             nonce_cache_size: 1024 * 1024,