`tagged_subqueries` move-in latency is ~15 seconds while regular replication is instant

[jbingen]

When using tagged_subqueries with a shape like:

WHERE id IN (SELECT user_id FROM workspace_members WHERE workspace_id = $1)

I'm seeing ~15 second latency for move-in events, while regular replication events are instant.

Observed behavior:

1. Insert a new workspace_members row → syncs to client in <1 second
2. The corresponding profiles move-in takes ~15 seconds to arrive
3. During this gap, the UI shows the new member but can't display their profile data

Expected behavior:

Move-in events should arrive with similar latency to regular replication events.

Environment:

• Electric server: electricsql/electric:latest on Railway
• Client: @electric-sql/pglite-sync 0.4.1

Questions:

• Is this expected behavior for the Materializer?
• Is there any configuration to reduce move-in latency?
• Is this something being optimized?