From eaa0f48e425cacb52824cbf14432cc83f409da99 Mon Sep 17 00:00:00 2001
From: koresar <kore.sar@gmail.com>
Date: Wed, 15 May 2024 21:16:27 +1000
Subject: [PATCH] Revert "fix: use the last most record in the DB as the
 balance snapshot upper boundary"

This reverts commit d37951d26708f1f9c961a0d9255b2854cbde764b.
---
 src/Book.ts | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/src/Book.ts b/src/Book.ts
index ba84288..8d1a5e4 100644
--- a/src/Book.ts
+++ b/src/Book.ts
@@ -22,6 +22,7 @@ const GROUP = {
     _id: null,
     balance: { $sum: { $subtract: ["$credit", "$debit"] } },
     notes: { $sum: 1 },
+    lastTransactionId: { $max: "$_id" },
   },
 };
 
@@ -109,9 +110,6 @@ export class Book<U extends ITransaction = ITransaction, J extends IJournal = IJ
     const partialBalanceOptions = { ...options };
     // If using a balance snapshot then make sure to use the appropriate (default "_id_") index for the additional balance calc.
     if (parsedQuery._id) partialBalanceOptions.hint =  { _id: 1 };
-    const lastCheckedTransaction = await transactionModel.collection
-      .findOne({}, { ...partialBalanceOptions, projection: { _id: 1 }, sort: { _id: -1 } });
-    const lastCheckedTransactionId = lastCheckedTransaction?._id;
     const result = (await transactionModel.collection.aggregate([match, GROUP], partialBalanceOptions).toArray())[0];
 
     let balance = 0;
@@ -126,8 +124,8 @@ export class Book<U extends ITransaction = ITransaction, J extends IJournal = IJ
       balance += parseFloat(result.balance.toFixed(this.precision));
       notes += result.notes;
 
-      // We can do snapshots only if there is at least one entry
-      if (this.balanceSnapshotSec && lastCheckedTransactionId) {
+      // We can do snapshots only if there is at least one entry for this balance
+      if (this.balanceSnapshotSec && result.lastTransactionId) {
         // It's the first (ever?) snapshot for this balance. We just need to save whatever we've just aggregated
         // so that the very next balance query would use cached snapshot.
         if (!balanceSnapshot) {
@@ -136,7 +134,7 @@ export class Book<U extends ITransaction = ITransaction, J extends IJournal = IJ
               book: this.name,
               account: accountForBalanceSnapshot,
               meta,
-              transaction: lastCheckedTransactionId,
+              transaction: result.lastTransactionId,
               balance,
               notes,
               expireInSec: this.expireBalanceSnapshotSec,
@@ -168,7 +166,7 @@ export class Book<U extends ITransaction = ITransaction, J extends IJournal = IJ
                     book: this.name,
                     account: accountForBalanceSnapshot,
                     meta,
-                    transaction: lastCheckedTransactionId,
+                    transaction: resultFull.lastTransactionId,
                     balance: parseFloat(resultFull.balance.toFixed(this.precision)),
                     notes: resultFull.notes,
                     expireInSec: this.expireBalanceSnapshotSec,