sincronizacao-e-armazenamento-offline-first

Record every local change in a mutation log with vector clocks while offline, then on reconnection exchange state vectors with the server and apply only the missing deltas inside protected transactions. Never download or replace the physical database file.

Delta-State CRDT synchronization sends only the incremental differences (deltas) between replicas instead of full state. The client computes its vector clock, the server replies with missing transaction deltas, and the client applies them sequentially in atomic batches.

Last-Write-Wins compares physical timestamps synchronized via NTP plus logical vector clocks for the same field edited on two devices. The edit with the most recent timestamp is persisted, while the losing change is discarded or archived in a reconciliation history table.

Avoid it for real-time keystroke-level collaborative typing in the same paragraph, which needs a dedicated rich-text CRDT editor skill, and for LGPD hard-delete operations that require physical removal of data blocks rather than logical replication.

Downloading the server's database file overwrites all offline modifications made on the device, causing irreversible loss. Replication must occur strictly at the level of logical transactions and incremental mutation logs, never raw file substitution.

Track logical record IDs and vector clocks consistently so the server can deduplicate incoming mutations. Duplicates typically appear when logical ID tracking fails during the reconnection handshake, so validate the mutation log before applying batches.