From 80822c722e3d0d658df39708ffe9f50f752ca6cc Mon Sep 17 00:00:00 2001
From: David Dworken <david@daviddworken.com>
Date: Tue, 20 Sep 2022 21:36:02 -0700
Subject: [PATCH] Optimize SQL query so it only runs one query rather than N

---
 backend/server/server.go | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/backend/server/server.go b/backend/server/server.go
index 3e2bf2a..412c2f5 100644
--- a/backend/server/server.go
+++ b/backend/server/server.go
@@ -277,17 +277,15 @@ func addDeletionRequestHandler(w http.ResponseWriter, r *http.Request) {
 }
 
 func applyDeletionRequestsToBackend(request shared.DeletionRequest) (int, error) {
-	numDeleted := 0
+	tx := GLOBAL_DB.Where("false")
 	for _, message := range request.Messages.Ids {
-		// TODO: Optimize this into one query
-		tx := GLOBAL_DB.Where("user_id = ? AND device_id = ? AND date = ?", request.UserId, message.DeviceId, message.Date)
-		result := tx.Delete(&shared.EncHistoryEntry{})
-		if result.Error != nil {
-			return 0, result.Error
-		}
-		numDeleted += int(result.RowsAffected)
+		tx = tx.Or(GLOBAL_DB.Where("user_id = ? AND device_id = ? AND date = ?", request.UserId, message.DeviceId, message.Date))
 	}
-	return numDeleted, nil
+	result := tx.Delete(&shared.EncHistoryEntry{})
+	if result.Error != nil {
+		return 0, result.Error
+	}
+	return int(result.RowsAffected), nil
 }
 
 func wipeDbHandler(w http.ResponseWriter, r *http.Request) {