From 9f527f10e1736b526c0bd3a3e743e3e7dc125e6e Mon Sep 17 00:00:00 2001
From: Brian Gough <briangough@users.noreply.github.com>
Date: Thu, 3 Apr 2025 11:24:59 +0100
Subject: [PATCH] Merge pull request #24104 from
 overleaf/bg-batched-update-concurrency-warning

prevent concurrent execution of batchedUpdate

GitOrigin-RevId: 90853ccd83943d8cd7b01fd11f152512d806e9a7
---
 libraries/mongo-utils/batchedUpdate.js | 106 ++++++++++++++-----------
 1 file changed, 58 insertions(+), 48 deletions(-)

diff --git a/libraries/mongo-utils/batchedUpdate.js b/libraries/mongo-utils/batchedUpdate.js
index 5e97f45aca..7e3ad677db 100644
--- a/libraries/mongo-utils/batchedUpdate.js
+++ b/libraries/mongo-utils/batchedUpdate.js
@@ -16,6 +16,7 @@ let VERBOSE_LOGGING
 let BATCH_RANGE_START
 let BATCH_RANGE_END
 let BATCH_MAX_TIME_SPAN_IN_MS
+let BATCHED_UPDATE_RUNNING = false
 
 /**
  * @typedef {import("mongodb").Collection} Collection
@@ -211,57 +212,66 @@ async function batchedUpdate(
   findOptions,
   batchedUpdateOptions
 ) {
-  ID_EDGE_PAST = await getIdEdgePast(collection)
-  if (!ID_EDGE_PAST) {
-    console.warn(
-      `The collection ${collection.collectionName} appears to be empty.`
-    )
-    return 0
+  // only a single batchedUpdate can run at a time due to global variables
+  if (BATCHED_UPDATE_RUNNING) {
+    throw new Error('batchedUpdate is already running')
   }
-  refreshGlobalOptionsForBatchedUpdate(batchedUpdateOptions)
-
-  findOptions = findOptions || {}
-  findOptions.readPreference = READ_PREFERENCE_SECONDARY
-
-  projection = projection || { _id: 1 }
-  let nextBatch
-  let updated = 0
-  let start = BATCH_RANGE_START
-
-  while (start !== BATCH_RANGE_END) {
-    let end = getNextEnd(start)
-    nextBatch = await getNextBatch(
-      collection,
-      query,
-      start,
-      end,
-      projection,
-      findOptions
-    )
-    if (nextBatch.length > 0) {
-      end = nextBatch[nextBatch.length - 1]._id
-      updated += nextBatch.length
-
-      if (VERBOSE_LOGGING) {
-        console.log(
-          `Running update on batch with ids ${JSON.stringify(
-            nextBatch.map(entry => entry._id)
-          )}`
-        )
-      } else {
-        console.error(`Running update on batch ending ${renderObjectId(end)}`)
-      }
-
-      if (typeof update === 'function') {
-        await update(nextBatch)
-      } else {
-        await performUpdate(collection, nextBatch, update)
-      }
+  try {
+    BATCHED_UPDATE_RUNNING = true
+    ID_EDGE_PAST = await getIdEdgePast(collection)
+    if (!ID_EDGE_PAST) {
+      console.warn(
+        `The collection ${collection.collectionName} appears to be empty.`
+      )
+      return 0
     }
-    console.error(`Completed batch ending ${renderObjectId(end)}`)
-    start = end
+    refreshGlobalOptionsForBatchedUpdate(batchedUpdateOptions)
+
+    findOptions = findOptions || {}
+    findOptions.readPreference = READ_PREFERENCE_SECONDARY
+
+    projection = projection || { _id: 1 }
+    let nextBatch
+    let updated = 0
+    let start = BATCH_RANGE_START
+
+    while (start !== BATCH_RANGE_END) {
+      let end = getNextEnd(start)
+      nextBatch = await getNextBatch(
+        collection,
+        query,
+        start,
+        end,
+        projection,
+        findOptions
+      )
+      if (nextBatch.length > 0) {
+        end = nextBatch[nextBatch.length - 1]._id
+        updated += nextBatch.length
+
+        if (VERBOSE_LOGGING) {
+          console.log(
+            `Running update on batch with ids ${JSON.stringify(
+              nextBatch.map(entry => entry._id)
+            )}`
+          )
+        } else {
+          console.error(`Running update on batch ending ${renderObjectId(end)}`)
+        }
+
+        if (typeof update === 'function') {
+          await update(nextBatch)
+        } else {
+          await performUpdate(collection, nextBatch, update)
+        }
+      }
+      console.error(`Completed batch ending ${renderObjectId(end)}`)
+      start = end
+    }
+    return updated
+  } finally {
+    BATCHED_UPDATE_RUNNING = false
   }
-  return updated
 }
 
 /**