SQL/MP Reference Manual

HP NonStop SQL/MP Reference Manual—523352-013
A-41
Considerations—ALTER TABLE
For a one-way split, the subvolume name and simple file name for the new
partition (whether specified explicitly or by default) must be identical to the
subvolume name and simple file name for every other partition of the same
object; ALTER TABLE uses those names if you specify only a node name and
volume name or specify only a volume name (which causes the node to default
to the local node). The combination of node name and volume name must be
unique for each partition of the same object.
The first part can be moved only if you include the WITH SHARED ACCESS
option.
A one-way split without the WITH SHARED ACCESS option requires additional
space on the disk that contains the partition being split while the split is in
progress. The amount of additional space required can be as much as the size
(EOF) of the original partition. A one-way split also requires space within the
file itself.
If you are splitting a partition because the disk is full (error 43), it might be
permissible to use a two-way split. If you choose to perform a one-way split,
use the WITH SHARED ACCESS option. Run a DSAP report to show the
largest number of pages of free space. After you successfully perform the
one-way split operation, run FUP RELOAD to reclaim unused space in the file.
For more information on FUP RELOAD, see the File Utility Program (FUP)
Reference Manual. You can also run DCOM on the disk to reclaim unused
space. For more information on DCOM, see the Guardian Disk and Tape
Utilities Reference Manual.
If you are splitting a partition because the file is full (error 45), increase
MAXEXTENTS for that file, if possible. Otherwise, perform a two-way split.
If you are splitting a partition because you received SQL error -1637 (“An
unexpected error occurred while purging data from filename”), verify that the
error was received against the source partition. If the error was on the
destination partition, specify smaller extent sizes based on the largest free
segment on that disc, or obtain a DSAP report and specify another volume
based on the largest free space available on another disk.
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A two-way split moves the first part of a partition to one new partition and the
last part of a partition to another new partition, deleting the original partition:
MOVE UP TO KEY val TO dest-part
FROM KEY val TO dest-part
In a two-way split, name specifies the partition for the operation.
Both occurrences of val must be identical, but each occurrence of
dest-part must specify a different partition. That is, the combination of node
name and volume name for a new partition (whether specified explicitly as
dest-part or by default) must be unique for each partition of the same
object. The subvolume name and simple file name for a new partition (whether
specified explicitly or by default) must be identical to the subvolume name and