SDS_TEMPDBS configuration parameter

Use the SDS_TEMPDBS configuration parameter to specify information that the shared disk (SD) secondary server uses to dynamically create temporary dbspaces. This configuration parameter can be specified only on the SD secondary server.

onconfig.std value
Not set. Temporary dbspaces for shared disk secondary servers are not created.
values
A string containing the following values in the following order, separated by commas:

dbspace = The name of the dbspace to create. Must be unique among all existing dbspaces, blobspaces, and sbspaces, including those any temporary spaces that are inherited from a primary server. The name cannot exceed 128 bytes. It must begin with a letter or underscore and must contain only letters, numbers, underscores, or the $ character.

dbpath = The path for the dbspace, either a full path name or a relative path name. If you use a relative path name, it must be relative to the directory that was the current directory when you initialized the database server.

pagesize = An integer representing the page size of the dbspace, in kilobytes. The page size must be between 2 KB and 16 KB and must be a multiple of the default page size.

offset = An integer equal to or greater than 0 that specifies offset into the disk partition or into the device to reach the initial chunk of the dbspace. The starting offset plus the chunk size cannot exceed the maximum chunk size. The offset must be a multiple of the page size. The maximum offset is 2 or 4 terabytes, depending on the platform. By default, the value is in kilobytes. You can designate different units by appending a single character modifier to the value: M or m for megabytes, G or g for gigabytes, or T or t for terabytes.

size = A positive integer equal to or greater than 1000 kilobytes and a multiple of the page size that specifies the size of the initial chunk of the dbspace. The value of offset plus the value of size cannot exceed the maximum chunk size. The maximum size of a chunk is equal to 2 147 483 647 pages multiplied by the page size. By default, the value is in kilobytes. You can designate different units by appending a single character modifier to the value: M or m for megabytes, G or g for gigabytes, or T or t for terabytes.

separators
Separate each value with a comma. Do not use blank spaces.
takes effect
After you edit your onconfig file and restart the SD secondary server.

Usage

The temporary dbspaces are created, or initialized if the dbspaces existed previously, when the SD secondary server starts. The temporary dbspaces are used for creating temporary tables. There must be at least one occurrence of the SDS_TEMPDBS configuration parameter in the onconfig file of the SD secondary server for the SD secondary server to start. You can specify up to 16 SD secondary temporary dbspaces in the onconfig file by using multiple occurrences of the SDS_TEMPDBS configuration parameter.

For each occurrence of the SDS_TEMPDBS configuration parameter in the onconfig file:
  • The dbsname value must unique for each server and not shared with any other SD secondary server or the primary server.
  • The combination of dbspath, pagesize, offset, and size must not cause any overlap with existing chunks or between temporary dbspaces spaces specified by the SDS_TEMPDBS configuration parameter.
  • The pagesize value must be the same for each SDS_TEMPDBS configuration parameter value.

The following example shows two entries for the SDS_TEMPDBS configuration parameter:

SDS_TEMPDBS sds_space1,/dev/raw_dev1,2,0,60M
SDS_TEMPDBS sds_space2,/dev/raw_dev2,2,0,80M

If the primary server in a high-availability cluster fails and an SD secondary server takes over as the primary server, then the value set for the SDS_TEMPDBS configuration parameter on the SD secondary server is used for temporary dbspaces until the server is restarted. You should ensure that the value specified for the SDS_TEMPDBS configuration parameter on the SD secondary server is different than the value specified on the primary server. After the SD secondary server is restarted, the DBSPACETEMP configuration parameter is used.


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