Upsert in Magma's YCSB perf tests is broken

During update operations with the upsert flag set, the https://github.com/couchbaselabs/YCSB/tree/couchbase3 benchmark we use uses the sdk collection.replace operations which does a lookup followed by an update operation. With the upsert flag it should be using the collection.upsert operation. This bug seems to be only in the couchbase3 YCSB client, couchbase2 is fine.

This issue results in Couchbase effectively doing two reads(one from sdk and one for item count in kv) and one write per update operation. This is broken for all of Magma's 1% dgm YCSB tests since we set the upsert flag in all of them.

Edit:

The methods which would have to be changed in the YCSB client are:

• https://github.com/couchbaselabs/YCSB/blob/couchbase3/couchbase3/src/main/java/com/yahoo/ycsb/db/couchbase3/Couchbase3Client.java#L398
• https://github.com/couchbaselabs/YCSB/blob/couchbase3/couchbase3/src/main/java/com/yahoo/ycsb/db/couchbase3/Couchbase3Client.java#L417