Fix Issue#2: Removing unnecessary rewrites of the backup file

kwertop · Mar 27, 2024 · 9c75610 · 9c75610
1 parent 33dfde4
commit 9c75610
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Showing 3 changed files with 15 additions and 0 deletions.
diff --git a/lib/persistentNodeCache.d.ts b/lib/persistentNodeCache.d.ts
@@ -12,6 +12,7 @@ export default class PersistentNodeCache extends NodeCache {
     private flushingToDisk;
     private appendFileDescriptor;
     private serializer;
+    private changesSinceLastBackup;
     constructor(cacheName: string, period?: number, dir?: string, opts?: any, serializer?: CacheSerializer);
     set<T>(key: Key, value: T, ttl?: number | string): boolean;
     mset<T>(keyValueSet: ValueSetItem<T>[]): boolean;

diff --git a/lib/persistentNodeCache.js b/lib/persistentNodeCache.js
@@ -54,6 +54,7 @@ class PersistentNodeCache extends node_cache_1.default {
             };
             this.serializer = customSerializer;
         }
+        this.changesSinceLastBackup = false;
         super.on("expired", (key, _) => { this.appendExpiredEvent(key); });
     }
     set(key, value, ttl) {
@@ -189,6 +190,9 @@ class PersistentNodeCache extends node_cache_1.default {
         this.appendToFile(this.appendFilePath, bf);
     }
     saveToDisk() {
+        if (!this.changesSinceLastBackup) {
+            return;
+        }
         this.flushingToDisk = true;
         try {
             let data = new Array();
@@ -212,10 +216,12 @@ class PersistentNodeCache extends node_cache_1.default {
         }
         finally {
             this.flushingToDisk = false;
+            this.changesSinceLastBackup = false;
             this.emitter.emit('done');
         }
     }
     appendToFile(fileName, data) {
+        this.changesSinceLastBackup = true;
         const flags = fs_1.default.constants.O_WRONLY | fs_1.default.constants.O_DIRECT | fs_1.default.constants.O_APPEND;
         const mode = 0o666;
         if (this.appendFileDescriptor) {

diff --git a/src/persistentNodeCache.ts b/src/persistentNodeCache.ts
@@ -27,6 +27,7 @@ export default class PersistentNodeCache extends NodeCache {
     private flushingToDisk: boolean;
     private appendFileDescriptor: any;
     private serializer: CacheSerializer;
+    private changesSinceLastBackup: boolean;
 
     constructor(cacheName: string, period?: number, dir?: string, opts?: any, serializer?: CacheSerializer) {
         super(opts);
@@ -58,6 +59,7 @@ export default class PersistentNodeCache extends NodeCache {
             }
             this.serializer = customSerializer;
         }
+        this.changesSinceLastBackup = false;
         super.on("expired", (key, _) => { this.appendExpiredEvent(key) });
     }
 
@@ -179,6 +181,10 @@ export default class PersistentNodeCache extends NodeCache {
     }
 
     private saveToDisk(): void {
+        if(!this.changesSinceLastBackup) {
+            return;
+        }
+
         this.flushingToDisk = true;
         try {
             let data: Array<ValueSetItem> = new Array<ValueSetItem>();
@@ -202,11 +208,13 @@ export default class PersistentNodeCache extends NodeCache {
         }
         finally {
             this.flushingToDisk = false;
+            this.changesSinceLastBackup = false;
             this.emitter.emit('done');
         }
     }
 
     private appendToFile(fileName: string, data: Buffer): void {
+        this.changesSinceLastBackup = true;
         const flags = fs.constants.O_WRONLY | fs.constants.O_DIRECT | fs.constants.O_APPEND;
         const mode = 0o666;