Problem Determination overview
When attempting to fix issues that occur in
Db2®, it is important to
determine the particular problem occurring. This section outlines problem determination for
different types of Db2 issues, including
traps hangs, and corruption.
Problem Determination: Traps
Traps are a specific type of crash, a term used to broadly describe any situation in which Db2 stops after encountering an unexpected condition. A trap occurs when a thread receives a signal or exception as the result of an instruction that cannot be executed by the operating system. For example, invalid memory access or a stack overflow could cause a trap. A trap is a specific term that should not be confused with "panic", "shutdown", "stop", or the more generic term "crash".
Problem Determination: Hangs
A hang is a situation in which the database stops responding to incoming requests, or stops processing existing requests. Typically, a hang occurs due to a shared resource (such as a lock or latch) already being held. Hangs can be either temporary, causing just a small slowdown, often indistinguishable from a performance problem, or permanent, occurring when the holder does not release the resource.
Problem Determination: Corruption
Data corruption in Db2 can be the source of crashes, panics, or forced database shutdowns. Data can become corrupt either physically or logically.