HP Neoview Release 2.4 Software - Manual (Page 81)

can execute in the master executor or ESP processes, and groupbys can execute in the master
executor, ESP, or ESAM processes.
Certain scan operators always execute in the same process. For example, the scan operators,
including FILE_SCAN and FILE_SCAN_UNIQUE, always execute in the ESAM process. The
ROOT operator always executes in the master executor process.
NPA plans only show the operators that represent the process boundaries and indicate the
number of processes used or accessed. They do not show each individual process involved in
executing the query.
Although the NPA plan appears to show only two processes, a root process and a ESAM process,
many other processes are used to execute the query plan. The plan shows the ROOT process and
15 ESAM processes. The notation 15–>1 indicates that 15 ESAM processes are used to perform
the file scan operation. The first number, 15, refers to the bottom partitioning information (in
this case, the file scan operation across 15 ESAM processes), and 1 refers to the root, or master
executor process where the information is rolled up.
Plan Summary and Operator Details
When you choose Explain from either the SQL Text or Query List frames, the initial display in
the right section of the Query Details is a summary of the plan. To see details about an operator,
select an operator in the tree. The Operator Details, which includes Cost Details and the
Description fields from the Explain output, is shown. To see the Plan Summary again, either use
the shortcut (Ctrl + click) or select the query from the SQL Text or Query List frames and choose
Explain
again.
The summary items shown in the Plan Summary are total counts of several operations. The fields
in the Plan Summary:
Description Field
Total number of ESP_EXCHANGE operators in this plan. ESP EXCHANGES
Total number of child processes counted for this plan. ESP PROCESSES
Total number of hash joins in this plan. HASH JOINS
Total number of merge joins in this plan. MERGE JOINS
Total number of nested joins in this plan. NESTED JOINS
Total joins in this plan. TOTAL JOINS
Total scans in this join (includes file and index scans). SCANS
Total number of sorts in this plan. SORTS
Total number of inserts, updates, and deletes in this plan. IUDs
Query Workbench Query Details 81