free known inventory of peer on disconnect (#1427)

* free known inventory of peer on disconnect

* free known inventory from heap by setting to nil

* move freeing of cache to closing of the quit channel

* skip dumping transactions for legacy mempool if block height is a pos block height

lib/legacy_mempool.go

@@ -789,6 +789,10 @@ func MakeDirIfNonExistent(filePath string) error {
 
 func (mp *DeSoMempool) OpenTempDBAndDumpTxns() error {
 	blockHeight := uint64(mp.bc.blockTip().Height + 1)
+	if mp.bc.params.IsPoSBlockHeight(blockHeight) {
+		glog.V(2).Infof("OpenTempDBAndDumpTxns: Not dumping mempool txns for PoS block %v", blockHeight)
+		return nil
+	}
 	allTxns := mp.readOnlyUniversalTransactionList
 
 	tempMempoolDBDir := filepath.Join(mp.mempoolDir, "temp_mempool_dump")

lib/peer.go

@@ -111,7 +111,7 @@ type Peer struct {
 
 	// Inventory stuff.
 	// The inventory that we know the peer already has.
-	knownInventory lru.Set[InvVect]
+	knownInventory *lru.Set[InvVect]
 
 	// Whether the peer is ready to receive INV messages. For a peer that
 	// still needs a mempool download, this is false.
@@ -652,7 +652,7 @@ func NewPeer(_id uint64, _conn net.Conn, _isOutbound bool, _netAddr *wire.NetAdd
 		outputQueueChan:        make(chan DeSoMessage),
 		peerDisconnectedChan:   peerDisconnectedChan,
 		quit:                   make(chan interface{}),
-		knownInventory:         *lru.NewSet[InvVect](maxKnownInventory),
+		knownInventory:         lru.NewSet[InvVect](maxKnownInventory),
 		blocksToSend:           make(map[BlockHash]bool),
 		stallTimeoutSeconds:    _stallTimeoutSeconds,
 		minTxFeeRateNanosPerKB: _minFeeRateNanosPerKB,
@@ -1365,6 +1365,10 @@ func (pp *Peer) Disconnect(reason string) {
 	// Signaling the quit channel allows all the other goroutines to stop running.
 	close(pp.quit)
 
+	// Free the cache of known inventory.
+	pp.knownInventory.Clear()
+	pp.knownInventory = nil
+
 	// Add the Peer to donePeers so that the ConnectionManager and Server can do any
 	// cleanup they need to do.
 	pp.peerDisconnectedChan <- pp