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

Parallelism
HP NonStop SQL/MX Query Guide—523728-003
8-19
Plan Fragments
Figure 8-5 shows the ESP_EXCHANGE node that forms the boundary between the
root fragment (master executor) and the first ESP fragment.
The EXPLAIN output for the ESP_EXCHANGE operator shows tokens in the
description that relate to the top degree parallelism (in this case, 1, indicating the
parallelism for the root fragment) and the bottom degree parallelism (in this case, 2,
Figure 8-4. Query Tree With ESP Parallelism
Figure 8-5. Plan Fragment Boundary
VST087.vsd
root [13]
hybrid_hash_join [9]
partition access [2]
esp exchange [8]
file_scan [1] - LINEITEM
merge_join [7]
esp exchange [12]
sort [11]
hash_groupby [10]
partition access [4]
partition access [6]
file_scan [3] - CUSTOMER
index_scan [5] - ORDERX1
VST088.vsd
root [13]
esp exchange [12]
sort [11]
Plan Fragment Boundary
Root Fragment
(Master Executor)
ESP Fragment