Unable to properly sync index from MongoDB to Meilisearch

[zjjxwhh]

What happened?

When I tried to update Meilisearch from getmeili/meilisearch:v1.7.3 to getmeili/meilisearch:v1.12.3, I deleted the data files for Meilisearch. After restarting the container, I found that LibreChat could not search previous conversation history. I checked the Meilisearch console and only saw data for the most recent few conversations, but LibreChat's logs indicated that the conversations had been fully synchronized.

I suspect there was an issue during synchronization; LibreChat believes all data has been synchronized, but in reality, that is not the case.

LibreChat/api/db/indexSync.js

Lines 53 to 78 in bc43423

	// Check if we need to sync messages
	const messageProgress = await Message.getSyncProgress();
	if (!messageProgress.isComplete) {
	logger.info(
	`[indexSync] Messages need syncing: ${messageProgress.totalProcessed}/${messageProgress.totalDocuments} indexed`,
	);
	// Check if we should do a full sync or incremental
	const messageCount = await Message.countDocuments();
	const messagesIndexed = messageProgress.totalProcessed;
	const syncThreshold = parseInt(process.env.MEILI_SYNC_THRESHOLD || '1000', 10);
	if (messageCount - messagesIndexed > syncThreshold) {
	logger.info('[indexSync] Starting full message sync due to large difference');
	await Message.syncWithMeili();
	messagesSync = true;
	} else if (messageCount !== messagesIndexed) {
	logger.warn('[indexSync] Messages out of sync, performing incremental sync');
	await Message.syncWithMeili();
	messagesSync = true;
	}
	} else {
	logger.info(
	`[indexSync] Messages are fully synced: ${messageProgress.totalProcessed}/${messageProgress.totalDocuments}`,
	);
	}

Version Information

• ghcr.io/danny-avila/librechat-dev:latest (sha256:a5d7771821937a95fa7b3125e51e7848f26d279850da0c2ed65782b90e63d2da)
• mongo:latest (sha256:a6bda40d00e56682aeaa1bfc88e024b7dd755782c575c02760104fe02010f94f)
• getmeili/meilisearch:v1.12.3 (sha256:4acfcbbb9e089aa1aac838cfda3fba7f07aaaef044c23da8acbe0ab741400dac)

Steps to Reproduce

1. Close all Docker containers related to LibreChat, such as librechat-dev, mongo, and Meilisearch
2. Delete the mounted data files from the host machine that are connected to the Meilisearch container
3. Restart the librechat-dev, mongo, and Meilisearch containers

What browsers are you seeing the problem on?

Chrome

Relevant log output

> [email protected] backend
> cross-env NODE_ENV=production node api/server/index.js
2025-08-02 19:50:58 info: Connected to MongoDB
2025-08-02 19:50:58 info: [indexSync] Starting index synchronization check...
2025-08-02 19:50:58 info: [indexSync] Messages are fully synced: 1120/1120
2025-08-02 19:50:58 info: [indexSync] Conversations are fully synced: 250/250

Screenshots

Code of Conduct

• I agree to follow this project's Code of Conduct

[danny-avila]

When manually deleting all meilisearch data, we can't know what's properly synced without doing an inefficient cross-reference.

What we can do is create a script to manually reset the _meiliIndex flag to false for all documents, so everything can be re-indexed on startup. Will push something up soon.

[zjjxwhh]

For others' reference:

1. Pull the latest ghcr.io/danny-avila/librechat-dev image and recreate the container using this image
2. Enter the container and execute npm run reset-meili-sync, then input y
3. Restart the container, the index will automatically synchronize