Setting Data Block Sizes Using the DBS Control Utility - Teradata Database

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Setting Data Block Sizes Using the DBS Control Utility

You can set data block sizes globally using these DBSControl fields: PermDBAllocUnit, PermDBSize, and JournalDBSize. These fields determine the maximum size of permanent data blocks that hold multiple rows. (A row that exceeds the size of a multirow data block is put into a block of its own.)


To change the PermDBSize, you need to use the modify and write commands of the DBS Control utility. The following example changes the data block size to 254 sectors:

1 From the command-line prompt (or the Supervisor window of the Database Window):


2 From the DBS Control window:

display FILESYS

3 Use the modify command to change flag 3 (PermDBSize):

modify FILESYS 3 = 254

4 Write the changes to the GDO:


Note: The default and minimum data block size depends on the cylinder size your site uses. Cylinder size is a global value, shown as:

  • Number of Disk Blocks Per Cylinder, using the PUT utility
  • SectsPerCyl, using the Filer utility FIB or SEGZERO command
  • Note: By default, Filer returns output from every vproc.