SQL/MP Installation and Management Guide

Format 2 Partitions
HP NonStop SQL/MP Installation and Management Guide—523353-004
C-6
General Planning Considerations
•
Partition management
Use the partition management functions to add new Format 2 partitions and to
populate those new partitions with data that currently resides in previously existing
Format 1 partitions. You must move partitions serially within a single table and all of
its indexes. After locating appropriate disk space for a new Format 2 partition,
perform a simple MOVE operation on the Format 1 partition to move it to a new
partition on a new disk as a Format 2 partition.
Using a round-robin approach, you can move the next Format 1 partition to the
space vacated by the previously moved partition, and so on until you have moved
all partitions that you intend to be Format 2. Alternatively, you can use a double-
move space management method. After you move each partition to free disk
space, you can move it back to the space vacated by its prior Format 1 location.
With this method, the same free disk space is used temporarily as each partition is
migrated in turn. This strategy has the disadvantage of doubling the move
operations but has the advantage of keeping individual partitions located on their
same disk volumes after the moves are completed.
•
SQL recompilation
If you have the Similarity Check feature enabled, no SQL recompilation is required.
Parallel Plans might require recompilation.
•
Limits evaluation
You should evaluate the new limits described earlier in this document for the
impact on their application. Special consideration should be given to the limits
based on the Format 2 block format in addition to the new maximum number of
partitions. The Format 2 block format has implications for maximum row size in
addition to disk space requirements.
•
Partition naming
The partition management functions used to migrate your data have an impact on
partition naming. After moving and merging individual partitions during migration,
partitions will have new names, which could have an impact on your application.
•
Queries against the SQL catalog
The FILES catalog table contains new columns, and any queries against it in your
applications might require changes.
•
Performance
You should expect similar performance for the same level of parallelism and
volume of data when contrasting the identical database with Format 1 and Format
2 partitions. As always, individual results vary, depending upon your application
and database. One way to manage performance expectations during migration is
to migrate keeping the same level of parallelism and volume of data. Check that all
data continues to be accessed from the same processor during all phases of
migration. Do not allow growth in the data stored in each partition. This strategy