SQL/MX 2.x Query Guide (G06.24+, H06.03+)

Parallelism
HP NonStop SQL/MX Query Guide—523728-003
8-23
Degree of Parallelism
Each SPLIT_TOP operator shows the top and bottom degree of parallelism. The
EXPLAIN output shows the three SPLIT_TOP operators from the query plan.
Seq_Num: 3
Operator: SPLIT_TOP
Left_Child_Seq_Num: 2
Right_Child_Seq_Num: ?
Cardinality: 3.2441872E+005
Operator Cost: 3.4873798E+000
Total Cost: 1.7911737E+001
Detail Cost: CPU_TIME: 3.843434 IO_TIME: 7.6177573495
MSG_TIME: 0 IDLETIME: 0.7 PROBES: 1
top_degree_parallelism: 1
bottom_degree_parallelism: 2
top_num_data_streams: 1
bottom_num_data_streams: 2
bottom_partitioning_function: logphys partitioned(grouping, PAPA
with 2 PA(s), log=exactly 1 partition, phys=range partitioned 2
ways on (([260]equiv(TPCD.XMPS.ORDERS.O_ORDERKEY) )))
Seq_Num: 6
Operator: SPLIT_TOP
Left_Child_Seq_Num: 5
Figure 8-8. Query Tree for Sample Plan Using DAM Parallelism
VST810.vsd
root [14]
hybrid_hash_join [11]
sort [13]
hash_groupby [12]
1
2(logphys)
Root Fragment
(Master Executor)
top_degree_parallelism
bottom_degree_parallelism
DAM Plan Fragments
split_top [3]
hybrid_hash_join [10]
1
1
2(logphys)
split_top [6]
2(logphys)
split_top [9]
partition access [5]
file_scan [4] - CUSTOMER
partition access [8]
index_scan [7] - ORDERX1
partition access [2]
file_scan [1] - LINEITEM