From a76721994412d03f478356ce95de17814dfbb082 Mon Sep 17 00:00:00 2001
From: Kevin Hahn <kevin_hahn@sil.org>
Date: Tue, 8 Oct 2024 00:10:39 +0700
Subject: [PATCH] instead of looking up all snapshot ids when there's more than
 10 commits, lookup just the ids for entities changed

---
 src/SIL.Harmony/DataModel.cs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/SIL.Harmony/DataModel.cs b/src/SIL.Harmony/DataModel.cs
index c8976f2..89be491 100644
--- a/src/SIL.Harmony/DataModel.cs
+++ b/src/SIL.Harmony/DataModel.cs
@@ -151,10 +151,13 @@ private async Task UpdateSnapshots(Commit oldestAddedCommit, Commit[] newCommits
     {
         await _crdtRepository.DeleteStaleSnapshots(oldestAddedCommit);
         Dictionary<Guid, Guid?> snapshotLookup;
-        //this is a performance optimization to avoid loading all the snapshots, this number is somewhat arbitrary
         if (newCommits.Length > 10)
         {
-            snapshotLookup = await _crdtRepository.CurrentSnapshots().ToDictionaryAsync(s => s.EntityId, s => (Guid?) s.Id);
+            var entityIds = newCommits.SelectMany(c => c.ChangeEntities.Select(ce => ce.EntityId));
+            snapshotLookup = await _crdtRepository.CurrentSnapshots()
+                .Where(s => entityIds.Contains(s.EntityId))
+                .Select(s => new KeyValuePair<Guid, Guid?>(s.EntityId, s.Id))
+                .ToDictionaryAsync(s => s.Key, s => s.Value);
         }
         else
         {