Entity Framework - Merge Records
How to Bulk Merge?
If you have a data (list of entities) which have both new and old records. SaveChanges requires one database round-trip to check if the entity already exist and one round-trip to insert or update the entity.
if you save 10,000 entities, 20,000 database round-trip will be performed which is INSANELY slow.
StackOverflow Related Questions
- MERGE in Entity Framework
- How can I use use Entity Framework to do a MERGE when I don't know if the record exists?
Entity Framework Extensions library adds the BulkMerge extension method to the DbContext. BulkMerge offers great customization and requires the minimum database round-trips as compared to SaveChanges.
// Easy to use ctx.BulkMerge(list); // Easy to customize context.BulkMerge(customers, options => options.ColumnPrimaryKeyExpression = customer => customer.Code);
MERGE all entities from the database. A merge is an UPSERT operation, all rows that match the entity key are considered as existing and are UPDATED, other rows are considered as new rows and are INSERTED in the database.
|Operations||1,000 Entities||2,000 Entities||5,000 Entities|
|SaveChange||1,000 ms||2,000 ms||5,000 ms|
|BulkMerge||65 ms||80 ms||110 ms|