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The CREATE TEMPSPACE statement defines and creates a temporary storage space
known as a TempSpace. A TempSpace is a location where ALLBASE/SQL
creates temporary files to store temporary data when performing
a sort, if disk space permits. Scope | |
ISQL or Application Programs SQL Syntax | |
CREATE TEMPSPACE TempSpaceName
WITH [MAXFILEPAGES = MaxTempFileSize,]LOCATION ='PhysicalLocation' |
Parameters | |
- TempSpaceName
is the logical name to be assigned to the new TempSpace.
More than one TempSpace can be defined but only one per physical
location. All TempSpace names must be unique within the DBEnvironment. - MaxTempFileSize
specifies the maximum number of 4096-byte pages
allocated for each temporary file in the PhysicalLocation. The number of pages must be a number between 128
and 524,284. The default is 256. Each file may grow in size up to
MaxTempFileSize. - PhysicalLocation
identifies the directory path where the TempSpace will be located. The directory
must exist prior to defining a TempSpace. A TempSpace is created
relative to the directory where the DBECon file resides unless an absolute
path name is specified. The maximum length for the path name is 35 bytes.
Description | |
If no TempSpaces are
defined for a DBEnvironment, sorting is done in the /tmp directory. It is recommended that each TempSpace reside in
a different disk partition. If TempSpaces are located in different
disk partitions, then the disk space of those partitions is available
for creating temporary files. Creating a single TempSpace per partition
is sufficient, because all TempSpaces on a particular partition
would share the space in that partition. When the size of a temporary file exceeds MaxTempFileSize pages, ALLBASE/SQL opens a temporary file in another
defined TempSpace. If additional TempSpace is not available, then
temporary files are created in the same TempSpace, if space permits. The total temporary space required for a DBEnvironment
depends on the size of the tables to be sorted or indexes to be
created. It also depends on the expected number of concurrent sort
operations on the system at one time. The MaxTempFileSize (of each file) should fit within the space available
in the partition where the TempSpace is located. Use the HP-UX
bdf command to determine the space available in a
partition. The location and characteristics of the TempSpace
are stored in the system catalog. TempSpace files are physically
created only when needed. When the TempSpace is no longer needed
(the present task completes), the temporary file or files are deleted
and the space is available for use again. The directory specified must be accessible to the
DBEnvironment. The directory must be accessible to hpdb for both read and write operations. If this read-write
(rw) capability is not granted or if the directory
does not exist when a TempSpace is created, errors are returned. If the TempSpace cannot be accessed when a statement
requiring temporary space is issued, a system error is returned
due to failure in opening the temporary file. To delete the definition of a TempSpace, use the
DROP TEMPSPACE statement.
Authorization | |
You must have DBA authority to use this statement. hpdb must
have write permission in the directory where the TempSpace files
will reside. Example | |
TempSpace temporary files are created in the /sort/PurchDB
directory when SQL Statements require sorting. CREATE TEMPSPACE ThisTempSpace WITH MAXFILEPAGES = 360,
LOCATION = '/sort/PurchDB' |
TempSpace temporary files are no longer available in the /sort/PurchDB,
directory but can be allocated under /tmp as needed. DROP TEMPSPACE ThisTempSpace |
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