Merge #143191

143191: kvserver: reset some fields of replicaAppBatch r=tbg a=pav-kv

This commit fixes a bug in `replicaAppBatch` initialization. Some fields were not reset, and would be carried across batches. For example, the `changeTruncatesSideloadedFiles` field, once set to true, would be true forever, and cause Pebble sync on every command application.

Epic: none
Release note: none

Co-authored-by: Pavel Kalinnikov <[email protected]>

Author: craig[bot]

pkg/kv/kvserver/replica_application_state_machine.go

@@ -138,6 +138,9 @@ func (sm *replicaStateMachine) NewEphemeralBatch() apply.EphemeralBatch {
 func (sm *replicaStateMachine) NewBatch() apply.Batch {
 	r := sm.r
 	b := &sm.batch
+	// TODO(pav-kv): replicaAppBatch initialization below is bug-prone, we need to
+	// not forget resetting the fields that are local to one batch. Find a way to
+	// make it safer.
 	b.r = r
 	b.applyStats = &sm.applyStats
 	b.batch = r.store.TODOEngine().NewBatch()
@@ -148,6 +151,9 @@ func (sm *replicaStateMachine) NewBatch() apply.Batch {
 	*b.state.Stats = *r.shMu.state.Stats
 	b.closedTimestampSetter = r.mu.closedTimestampSetter
 	r.mu.RUnlock()
+	b.changeRemovesReplica = false
+	b.changeTruncatesSideloadedFiles = false
+	// TODO(pav-kv): what about b.ab and b.followerStoreWriteBytes?
 	b.start = timeutil.Now()
 	return b
 }