diff --git a/src/flags.js b/src/flags.js
index c445d4de73..32ab355879 100644
--- a/src/flags.js
+++ b/src/flags.js
@@ -348,6 +348,7 @@ Flags.create = async function (type, id, uid, reason, timestamp) {
 			flagId: flagId,
 			type: type,
 			targetId: id,
+			targetUid: targetUid,
 			datetime: timestamp,
 		}),
 		Flags.addReport(flagId, type, id, uid, reason, timestamp),
@@ -573,8 +574,7 @@ Flags.resolveFlag = async function (type, id, uid) {
 Flags.getHistory = async function (flagId) {
 	const uids = [];
 	let history = await db.getSortedSetRevRangeWithScores('flag:' + flagId + ':history', 0, -1);
-	const flagData = await db.getObjectFields('flag:' + flagId, ['type', 'targetId']);
-	const targetUid = await Flags.getTargetUid(flagData.type, flagData.targetId);
+	const targetUid = await db.getObjectField('flag:' + flagId, 'targetUid');
 
 	history = history.map(function (entry) {
 		entry.value = JSON.parse(entry.value);
diff --git a/src/upgrades/1.15.0/add_target_uid_to_flags.js b/src/upgrades/1.15.0/add_target_uid_to_flags.js
new file mode 100644
index 0000000000..961231fc8d
--- /dev/null
+++ b/src/upgrades/1.15.0/add_target_uid_to_flags.js
@@ -0,0 +1,37 @@
+'use strict';
+
+const db = require('../../database');
+const batch = require('../../batch');
+const posts = require('../../posts');
+
+module.exports = {
+	name: 'Add target uid to flag objects',
+	timestamp: Date.UTC(2020, 7, 22),
+	method: async function () {
+		const progress = this.progress;
+
+		await batch.processSortedSet('flags:datetime', async function (flagIds) {
+			progress.incr(flagIds.length);
+			const flagData = await db.getObjects(flagIds.map(id => 'flag:' + id));
+			for (const flagObj of flagData) {
+				/* eslint-disable no-await-in-loop */
+				if (flagObj) {
+					const targetId = flagObj.targetId;
+					if (targetId) {
+						if (flagObj.type === 'post') {
+							const targetUid = await posts.getPostField(targetId, 'uid');
+							if (targetUid) {
+								await db.setObjectField('flag:' + flagObj.flagId, 'targetUid', targetUid);
+							}
+						} else if (flagObj.type === 'user') {
+							await db.setObjectField('flag:' + flagObj.flagId, 'targetUid', targetId);
+						}
+					}
+				}
+			}
+		}, {
+			progress: progress,
+			batch: 500,
+		});
+	},
+};