Merge #24612

24612: workload: tpcc: fix partitioning of history table r=arjunravinarayan a=arjunravinarayan

The previous partitioning code was incorrectly ported from loadgen, as
the Cockroach UUID library doesn't work with a direct SetBytes.

The previous code panicked with the following error:

```
panic: Couldn't exec ALTER TABLE history PARTITION BY RANGE (rowid) (
  PARTITION p0 VALUES FROM ('00000000-0000-0000-0000-000000000000') to ('00000000-0000-0000-0000-000000000000'),
  PARTITION p1 VALUES FROM ('00000000-0000-0000-0000-000000000000') to ('00000000-0000-0000-0000-000000000000'),
  PARTITION p2 VALUES FROM ('00000000-0000-0000-0000-000000000000') to ('00000000-0000-0000-0000-000000000000'),
  PARTITION p3 VALUES FROM ('00000000-0000-0000-0000-000000000000') to ('00000000-0000-0000-0000-000000000000'),
  PARTITION p4 VALUES FROM ('00000000-0000-0000-0000-000000000000') to ('00000000-0000-0000-0000-000000000000'),
  PARTITION p5 VALUES FROM ('00000000-0000-0000-0000-000000000000') to ('00000000-0000-0000-0000-000000000000'),
  PARTITION p6 VALUES FROM ('00000000-0000-0000-0000-000000000000') to ('00000000-0000-0000-0000-000000000000'),
  PARTITION p7 VALUES FROM ('00000000-0000-0000-0000-000000000000') to ('00000000-0000-0000-0000-000000000000'),
  PARTITION p8 VALUES FROM ('00000000-0000-0000-0000-000000000000') to ('00000000-0000-0000-0000-000000000000'),
  PARTITION p9 VALUES FROM ('00000000-0000-0000-0000-000000000000') to ('ffffffff-ffff-ffff-ffff-ffffffffffff')
)
: pq: PARTITION p0: empty range: lower bound ('00000000-0000-0000-0000-000000000000') is equal to upper bound ('00000000-0000-0000-0000-000000000000')
```

The modified code partitions successfully.

Co-authored-by: Arjun Narayan <[email protected]>

pkg/workload/tpcc/partition.go

@@ -230,13 +230,21 @@ func partitionCustomer(db *gosql.DB, wIDs []int, partitions int) {
 
 func partitionHistory(db *gosql.DB, wIDs []int, partitions int) {
 	const maxVal = math.MaxUint64
+	temp := make([]byte, 16)
 	rowids := make([]uuid.UUID, partitions+1)
 	for i := 0; i < partitions; i++ {
+		var err error
+
 		// We're splitting the UUID rowid column evenly into N partitions. The
 		// column is sorted lexicographically on the bytes of the UUID which means
 		// we should put the partitioning values at the front of the UUID.
-		binary.BigEndian.PutUint64(rowids[i].GetBytes()[:], uint64(i)*(maxVal/uint64(partitions)))
+		binary.BigEndian.PutUint64(temp, uint64(i)*(maxVal/uint64(partitions)))
+		rowids[i], err = uuid.FromBytes(temp)
+		if err != nil {
+			panic(err)
+		}
 	}
+
 	rowids[partitions], _ = uuid.FromString("ffffffff-ffff-ffff-ffff-ffffffffffff")
 
 	var buf bytes.Buffer