Notes Replication: Outstanding in Its Field

Lotus has optimized replication in Notes 4.0. The most visible change is field-level replication. In previous releases, any change in a document or attachment caused the entire contents of the document to be replicated. Now, only changes to individual fields are transmitted.

To further speed things up, Lotus made changes to the data structure and in Notes' use of remote procedure calls (RPCs). In release 3.0, at the start of replication, a command was sent to the server to build a dynamic list in memory of changes to documents. Release 4.0 moves these functions into t he Notes NSF database structure, keeping an index of all documents and fields a nd their time stamps available at each end of the replication session.

Instead of sending individual Universal Notes IDs (UNIDs) via multiple RPC calls, now a single RPC call contains a list of unique IDs. More information is included in each RPC packet, with more processing done on each end. Release 4.0 servers can also now have up to four concurrent replicators in action, speeding simultaneous replication between multiple servers.

Field-level replication also helps in conflict resolution. In release 3.0, a save conflict occurs if two users edit the same document at the same time, even if they're editing different fields. Release 4.0 lets a designer tell Notes to merge conflicting edits into a single document, provided that the conflict is not with the same field.

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Leaner and Meaner

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Notes 4.0's field-level replication takes a fraction of the time required for Notes 3.0's file-level approach.