set index compression argument: Change index page compression (SQL administration API)

Use the set index compression argument with the admin() or task() function to modify the level at which two partially used index pages are merged.

Syntax

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>>-EXECUTE FUNCTION--+-admin-+--(------------------------------->
                     '-task--'      

                                                      .-"med"-----.         
>--"set index compression"--,--"partition_number"--,--+-----------+--)--;-><
                                                      +-"default"-+         
                                                      +-"high"----+         
                                                      '-"low"-----'         

Element Description Key Considerations
partition_number The partition number. Find the partition numbers in the partnum column of the systables system catalog table.

Usage

Use this function to adjust index page compression. The pages are merged if the data on those pages totals a set level. To optimize space and transaction processing, you can lower the compression level if your indexes grow quickly. You can increase the level if your indexes have few delete and insert operations or if batch updates are performed.

Use the low argument if you expect an index to grow quickly with frequent splits.

Use the med or default argument if an index has moderate growth or changes.

Use the high argument if an index is 90 percent or more read-only or does not have many changes.

This function is equivalent to the onmode -C command and the compression option of the BTSCANNER configuration parameter.

Example

The following example sets index compression for a partition to high:
EXECUTE FUNCTION task("set index compression","1048611","high");

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