Use orphaned docs as part of GC calculation (#1355)

* Use orphaned documents in sequence number count

Author: Greg Soltis

packages/firestore/src/local/indexeddb_persistence.ts

@@ -1075,8 +1075,23 @@ export class IndexedDbLruDelegate implements ReferenceDelegate, LruDelegate {
     this.garbageCollector = new LruGarbageCollector(this);
   }
 
-  getTargetCount(txn: PersistenceTransaction): PersistencePromise<number> {
-    return this.db.getQueryCache().getQueryCount(txn);
+  getSequenceNumberCount(
+    txn: PersistenceTransaction
+  ): PersistencePromise<number> {
+    const docCountPromise = this.orphanedDocmentCount(txn);
+    const targetCountPromise = this.db.getQueryCache().getQueryCount(txn);
+    return targetCountPromise.next(targetCount =>
+      docCountPromise.next(docCount => targetCount + docCount)
+    );
+  }
+
+  private orphanedDocmentCount(
+    txn: PersistenceTransaction
+  ): PersistencePromise<number> {
+    let orphanedCount = 0;
+    return this.forEachOrphanedDocumentSequenceNumber(txn, _ => {
+      orphanedCount++;
+    }).next(() => orphanedCount);
   }
 
   forEachTarget(

packages/firestore/src/local/lru_garbage_collector.ts

@@ -36,7 +36,9 @@ export interface LruDelegate {
     f: (target: QueryData) => void
   ): PersistencePromise<void>;
 
-  getTargetCount(txn: PersistenceTransaction): PersistencePromise<number>;
+  getSequenceNumberCount(
+    txn: PersistenceTransaction
+  ): PersistencePromise<number>;
 
   /**
    * Enumerates sequence numbers for documents not associated with a target.
@@ -146,7 +148,7 @@ export class LruGarbageCollector {
     txn: PersistenceTransaction,
     percentile: number
   ): PersistencePromise<number> {
-    return this.delegate.getTargetCount(txn).next(targetCount => {
+    return this.delegate.getSequenceNumberCount(txn).next(targetCount => {
       return Math.floor(percentile / 100.0 * targetCount);
     });
   }

packages/firestore/src/local/memory_persistence.ts

@@ -317,8 +317,25 @@ export class MemoryLruDelegate implements ReferenceDelegate, LruDelegate {
     return this.persistence.getQueryCache().forEachTarget(txn, f);
   }
 
-  getTargetCount(txn: PersistenceTransaction): PersistencePromise<number> {
-    return this.persistence.getQueryCache().getTargetCount(txn);
+  getSequenceNumberCount(
+    txn: PersistenceTransaction
+  ): PersistencePromise<number> {
+    const docCountPromise = this.orphanedDocumentCount(txn);
+    const targetCountPromise = this.persistence
+      .getQueryCache()
+      .getTargetCount(txn);
+    return targetCountPromise.next(targetCount =>
+      docCountPromise.next(docCount => targetCount + docCount)
+    );
+  }
+
+  private orphanedDocumentCount(
+    txn: PersistenceTransaction
+  ): PersistencePromise<number> {
+    let orphanedCount = 0;
+    return this.forEachOrphanedDocumentSequenceNumber(txn, _ => {
+      orphanedCount++;
+    }).next(() => orphanedCount);
   }
 
   forEachOrphanedDocumentSequenceNumber(