Monday, January 7, 2013

Minicylpack in Teradata

MINICYLPACK is File system activity and is handled by Teradata by default.
This activity will exactly free one cylinder in an AMP and it is run automatically when the user request would need free cylinder or huge amount of space.
Cylinders are dedicated for PERM and SPOOL space separately.

MINICYLPACK is kind of last resort in system when the system is completely out of space and it is initiated. The Teradata file system will start to minicylpack when the number of free cylinders drops to the value set by MiniCylPackLowCylProd. The default is 10.

Say in above scenario, an AMP with 6 cylinders, the MiniCylPackLowCylProd is set to 1.
When the number of free cylinders goes below 1 i.e. 0, MINICYLPACKS is initiated and one cylinder is freed up during the process.

MINICYLPACK is resource intense activity because it causes lot of I/O's  in process of freeing up the data blocks  . It is suggested to run SHOWFSP from Ferret to see number of free cylinders available and cylinders that can be freed up and run PACKDISK to avoid unnecessary MINICYLPACK's

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