SQL/MP Installation and Management Guide

The SQL/MP Database Management Environment
HP NonStop SQL/MP Installation and Management Guide—523353-004
1-8
Parallel Processing
Parallel Processing
The following types of parallel processing are available in SQL/MP:
•
Parallel query processing
•
Parallel join operations
•
Parallel index maintenance
•
Parallel index loading
•
Parallel sorting
•
Parallel input-output operations
Parallel query processing can provide speed-up and scale-up. Speed-up is the
reduction of response time, which you can accomplish by spreading the database over
multiple partitions. Scale-up is the maintenance of a constant response time through
database growth, which you can accomplish by increasing the number of partitions.
When tables and indexes are partitioned across multiple disks, SQL/MP can use a
different process for each partition during query execution. This approach reduces the
time for scans and other set-oriented processing by a factor equivalent to the number
of partitions when there is no contention in the processor-controller disk path; that is,
when every participating disk is primary to a different processor.
Parallel join operations are performed by the SQL executor during query processing.
Parallel index maintenance reduces the effect of multiple indexes on performance.
Each index on a table is automatically updated whenever a row is inserted into the
table and whenever a value is updated in any key column of the index. Multiple
indexes on a table can be updated in parallel by different disk processes or by the
same disk process servicing multiple requests.
Parallel index loading speeds the loading of a partitioned index by loading all partitions
of the index at the same time. A different process loads each partition.
Parallel sorting is performed by the FastSort product, which SQL/MP uses for sort
operations. You can configure subsort processes for parallel sort operations.
Parallel input-output operations are performed on multiple partitions by different disk
processes. A single disk process can also perform parallel I/O by buffering operations
in cache.
High Availability
SQL/MP has these features to help ensure high availability for databases:
•
Online dumps using the TMFCOM DUMP FILES command, with complete support
for TMF file recovery to recover a database in case of a disaster
•
Online database reorganization capabilities such as online index creation with
concurrent read and update capability; online partition moving; partition splitting;