Determining When to Use Dataskip

Use this feature sparingly and with caution because the results are always suspect. Consider using it in the following situations:

• You can accept the compromised integrity of transactions.
• You can determine that the integrity of the transaction is not compromised.

The latter task can be difficult and time consuming.

Determining When to Skip Selected Fragments

In certain circumstances, you might want the database server to skip some fragments, but not others. This usually occurs in the following situations:

• Fragments can be skipped because they do not contribute significantly to a query result.
• Certain fragments are down, and you decide that skipping these fragments and returning a limited amount of data is preferable to canceling a query.

When you want to skip fragments, use the ON dbspace-list setting to specify a list of dbspaces with the fragments that the database server should skip.

Determining When to Skip All Fragments

Setting the DATASKIP configuration parameter to ALL causes the database server to skip all unavailable fragments. Use this option with caution. If a dbspace becomes unavailable, all queries initiated by applications that do not issue a SET DATASKIP OFF statement before they execute could be subject to errors.