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Databases & messaging · #realm
When updating a small Android application using Realm, maintaining session continuity during a schema migration is critical to avoid runtime crashes. The goal is to determine the safest approach for applying schema changes without interrupting active user sessions. Automatic migrations simplify deployment by handling schema changes at runtime, but they may t
Problem Context After moving the Realm Object Server to a new IP address, clients report a persistent connection timeout when attempting to open a synced Realm. The SDK continues to use the previous DNS entry, resulting in a failed WebSocket handshake. Constraints & Uncertainty The Realm SDK relies on the platform’s DNS resolver, which may cache entries
When a migration block throws an exception, Realm throws a MigrationException (or RealmMigrationNeededException in older versions) and refuses to open the Realm file. The documented recovery paths are implementing a correct migration block or enabling deleteRealmIfMigrationNeeded=true to wipe the database. However, the documentation does not explicitly guara
In Realm 10.12, the schemaVersion property and migration block enable forward‑only schema changes. Once a migration has been applied, the Realm file header records the highest version written. The documented behavior states that attempting to open the file with a lower schemaVersion triggers an error or requires the file to be deleted before reopening. Devel
A Realm file encrypted with AES-256 opens successfully in one environment but fails to open in another when the same file path and SDK are used. The encryption key is supplied at open time and is not stored inside the file. The goal is to confirm whether the production runtime supplies the identical 64-byte key used to create the Realm, and whether the targe
Choice Between Discard and Recovery After a Failed Upgrade A failed app upgrade that changes the sync schema or leaves the client and server out of step can force a client reset in MongoDB Realm / Atlas Device Sync before the local realm can sync again. The immediate engineering decision is whether to discard unsynced local writes and download a clean server
Fine-grained Notification Management Realm Java/Kotlin SDKs provide ChangeSet objects within collection listeners to identify specific insertions, deletions, and modifications. While this allows for precise UI updates, a challenge arises when managing high-frequency write operations across large datasets where only a subset of changes is relevant to the curr
We are evaluating sync latency between the Realm mobile client and Sync Server in current SDKs before optimization. The goal is to baseline how long a batch write takes to propagate and become observable through change notifications. Realm's change notification mechanism relies on JSON patch semantics, delivering diffs only when property values change, creat
Designing ownership boundaries for Realm instances and change listeners when an Android screen is tied to AndroidX Lifecycle requires a clear interoperability contract between the Realm Kotlin SDK and Lifecycle components. The SDK is thread-confined and historically requires explicit close. RealmChangeListeners and Kotlin Flows derived from Realm objects can
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