Informix database servers are designed to detect database server malfunctions or problems caused by hardware or operating-system errors. It detects problems by performing assertions in many of its critical functions. An assertion is a consistency check that verifies that the contents of a page, structure, or other entity match what would otherwise be assumed.
When one of these checks finds that the contents are not what they should be, the database server reports an assertion failure and writes text that describes the check that failed in the database server message log. The database server also collects further diagnostics information in a separate file that might be useful to IBM Technical Support staff.
This chapter provides an overview of consistency-checking measures and ways of handling inconsistencies. It covers the following topics: