From fc7c30a3b0e9f9db2d7260f32bb80d26d0cf98e1 Mon Sep 17 00:00:00 2001
From: Ralf Kistner <ralf@journeyapps.com>
Date: Tue, 10 Dec 2024 16:15:52 +0200
Subject: [PATCH 1/2] Update MongoDB docs on permissions and postImages.

---
 installation/database-setup.mdx | 55 +++++++++++++++++++++++++++++++--
 1 file changed, 52 insertions(+), 3 deletions(-)

diff --git a/installation/database-setup.mdx b/installation/database-setup.mdx
index 6c4a9ab0..a10e774b 100644
--- a/installation/database-setup.mdx
+++ b/installation/database-setup.mdx
@@ -348,11 +348,60 @@ Notably, some "serverless Postgres" providers do not support logical replication
 **Version compatibility**: PowerSync requires MongoDB version 6.0 or greater.
 </Check>
 
-PowerSync requires the `find` and `changeStream` permissions on all databases and collections.
+### Permissions required - MongoDB Atlas
 
-PowerSync also requires `createCollection`, `insert`, `update`, and `remove` permissions to the `_powersync_checkpoints` collection.
+For MongoDB Atlas databases, the minimum permissions are:
 
-For MongoDB Atlas users, PowerSync requires `readWrite@mydb._powersync_checkpoints` and `readAnyDatabase@admin`
+```
+readWrite@<your_database>._powersync_checkpoints
+read@<your_database>
+```
+
+To allow PowerSync to automatically configure enable `changeStreamPreAndPostImages` on
+replicated collections, instead use:
+
+```
+dbAdmin@<your_database>
+```
+
+If you are replicating from multiple databases in the cluster, you need read permissions on the entire cluster:
+
+```
+readAnyDatabase@admin
+```
+
+
+### Permissions required - Self-hosted
+
+For self-hosted MongoDB, PowerSync requires the `find` and `changeStream` permissions on the database being replicated.
+
+PowerSync also requires `createCollection`, `dropCollection`, `insert`, `update`, and `remove` permissions to the `_powersync_checkpoints` collection.
+
+### postImages
+
+To replicate data from MongoDB to PowerSync in a consistent manner, PowerSync
+uses Change Streams with `fullDocument: 'required'` to get postImages with every change.
+For this to work, `changeStreamPreAndPostImages` must be enabled on every replicated collection.
+
+A PowerSync instance can be configured to enable this automatically, if it has
+sufficient permissions (see permissions above). Alternatively, run this on every collection:
+
+```js
+db.runCommand({
+  collMod: COLLECTION_NAME,
+  changeStreamPreAndPostImages: { enabled: true }
+})
+```
+
+You can view which collections have the option enabled using:
+
+```js
+db.getCollectionInfos().filter(c => c.options?.changeStreamPreAndPostImages?.enabled)
+```
+
+A PowerSync instance can alternative be configured to replicate using `fullDocument: 'updateLookup'`.
+This was the default for older instances. However, this may lead to consistency issues,
+so we strongly recommend enabling postImages support instead.
 
 ## <Icon icon="dolphin" iconType="solid" size="24"/> MySQL (Alpha)
 

From 729777c5d2b14fe88a930cbf4c1120fb6b942a46 Mon Sep 17 00:00:00 2001
From: benitav <benitav@users.noreply.github.com>
Date: Wed, 11 Dec 2024 08:56:56 +0200
Subject: [PATCH 2/2] Update installation/database-setup.mdx

---
 installation/database-setup.mdx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/installation/database-setup.mdx b/installation/database-setup.mdx
index a10e774b..64c30c17 100644
--- a/installation/database-setup.mdx
+++ b/installation/database-setup.mdx
@@ -399,7 +399,7 @@ You can view which collections have the option enabled using:
 db.getCollectionInfos().filter(c => c.options?.changeStreamPreAndPostImages?.enabled)
 ```
 
-A PowerSync instance can alternative be configured to replicate using `fullDocument: 'updateLookup'`.
+A PowerSync instance can alternatively be configured to replicate using `fullDocument: 'updateLookup'`.
 This was the default for older instances. However, this may lead to consistency issues,
 so we strongly recommend enabling postImages support instead.