What is CrashDumps, how these will be usefull in Teradata RDBMS. How these will be operated when failures happend? Could you please share your ideas with me, i don't have much knowledge about these CrashDumps.
The term 'crashdump' in Teradata land is used colloquially to mean the contents of memory that is dumped out to disk whenever the system crashes or encounters a fatal/critical error.
In actuality however, there are two forms of teradata dumps: crashdumps and snapshot dumps. For all that matters, the two are handled the same way. The major difference is that a crashdump occurs when the system crashes (all nodes are dumped and restart occurs) whereas a snapshot dump occurs due to an error condition(only relevant nodes are dumped and there is no restart).
The Teradata database is coded in such a way to work around errors that may occur when a query is in either the parsing or optimizer phases.
These errors are like: 3610 (internal p****r errors) or segmentation violation (i.e. when a query tries to access a reserved section of memory - ofcourse it a bit more complicated than just this). However: If the system encounters such an error, instead of restarting the database, the contents of memory are written out to disk (snapshot dump). For UNIX system, there is a dedicated dump slice where this data is written. In Windows, the dump is saved in flat files until it is processed.
After a dump is processed it is saved to the 'crashdumps' database (after all, a crashdump (or snapshot dump) is just rows that were being processed at the time of the error). Whether or not a system is set to automatically save dumps is tunable and is controlled by a Control flag.
Thanks for reply, Ur respons was very useful to begin with the CrashDumps topic.I am Practicing to create the CrashDumps (PDE, system, and DBS dumps). But How do i create Crashdump files (.dbm) and how can i transfer that .dbm files to the DBC.CrashDumps Database(I have Created CrashDump Database, my oS is Windows). What are the tables do i need to create with in the DBC.CrashDumps Database. Could you help me.