SQL/MP Programming Manual for COBOL85

Explicit Program Compilation
HP NonStop SQL/MP Programming Manual for COBOL85—429326-004
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Using CONTROL Directives
The catalog name is not included in the SQLCOMP command because it is stored in
the program file. The NOOBJECT option suppresses the generation of a new object
file, so the SQL compiler does not register the program file in a catalog.
SQLCOMP /IN SQLPROG,OUT $S.#EXPLAIN/ NOOBJECT,
EXPLAIN PLAN DEFINES SETDEFS, OBEYFORM
For more information about the EXPLAIN utility, including detailed examples and
reports, see the SQL/MP Query Guide.
Using CONTROL Directives
You can use these CONTROL directives with either static or dynamic SQL statements
in a COBOL program:
CONTROL EXECUTOR
allows or prohibits parallel execution of a query by multiple SQL executor. Parallel
execution can decrease the elapsed time for processing a query.
CONTROL QUERY
controls query execution plans as follows:
•
Optimization of query response time for returning only the first few rows found
or for returning all rows found
•
Use of hash join algorithms in execution plans
•
Use of execution-time name resolution to resolve names in execution plans
when the SQL statement executes rather than during explicit SQL compilation
or at SQL load time
CONTROL TABLE
controls these performance-related options for accessing tables and views:
•
Selection of access paths, join methods, join sequences, and lock types
•
Selection of block buffering and block splitting algorithms
•
Action to take for locked data or unavailable partitions
•
Opening of indexes and partitions at the initial access to a table
•
Checkpointing of unaudited write operations
The use of CONTROL directives in a COBOL program is discussed next. For the
syntax of each CONTROL directive, see the SQL/MP Reference Manual.