SQL/MX Comparison Guide for SQL/MP Users

Comparing the Differences in the Products
HP NonStop SQL/MX Comparison Guide for SQL/MP Users—523735-003
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What’s New in NonStop SQL/MX?
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#XFILENAMES
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#XFILES
In general, the commands work the same and return the same information for
SQL/MX objects as they do for non-SQL/MX objects. Exceptions are noted in the
TACL Reference Manual.
These commands return errors when used with SQL/MX objects and are not
supported:
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COPYDUMP
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PURGE
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RENAME
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#PURGE
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#RENAME
What’s New in NonStop SQL/MX?
Redesigned Optimizer and Executor
NonStop SQL/MX uses a redesigned optimizer and executor. The top-down, cost-
based, rules-driven optimizer considers more plans than NonStop SQL/MP.
Extensibility is provided through the compiler, because new transformations using rules
can be added with ease to the optimizer. The redesigned executor also provides
extensibility that uses a data-flow architecture. The executor takes advantage internally
of completely no-waited operations and provides for more work in the HP NonStop
Data Access Manager (DAM), including multiple forms of parallelism and scalability on
multiple levels.
For additional information about differences between the SQL/MP and SQL/MX
optimizer features, see Section 5, Optimizer and Executor.
Performance
In addition to considering many more plans, the SQL/MX optimizer allows you to push
down certain plans that involve compound statements or nested joins into the Data
Access Manager. You can influence a query plan by rewriting portions of a plan with
the CONTROL QUERY SHAPE command. NonStop SQL/MX provides histogram
statistics that provide more accurate statistics of the data in the database. These
statistics are also used by the optimizer to create efficient query plans.
For additional information about optimizer features, see Section 5, Optimizer and
Executor.
Parallel Operations for Scalable High Performance
NonStop SQL/MX can execute large queries that scan large portions of the database in
parallel. Although NonStop SQL/MX supports three basic forms of parallelism,
partitioned parallelism is the main type of parallelism used. Partitioned parallelism is