Common Informix OLTP Error Messages
What are the most common Informix-related errors that a user may encounter for an OLTP application?
Red Valsen wrote: > > What are the most common Informix-related errors that a user may > encounter for an OLTP application? I don't think I understand the question. Could you please clarify?? -- John Carlson Informix DBA WHSmith USA #include std_disclaimer.h /* These are my opinions, not my company's opinion */
What are the most likely errors that I would encounter as a user sitting down to an OLTP application (e.g., a personnel/benefits system, order entry system, retail transactions system) which are related to the application's use of the DBMS? For example, I try to update a field on which a check constraint has been placed, but which may not be trapped first by the GUI portion of the application; or I attempt to add an entry for new customer "Red Valsen," but the record already exists. We are attempting to write a generic Java class which adequately handles most SQL-related errors, including giving users non-cryptic (or even helpful) error messages. "Carlson@WHSmith" wrote: > Red Valsen wrote: > > > > What are the most common Informix-related errors that a user may > > encounter for an OLTP application? > > I don't think I understand the question. Could you please clarify?? > -- > John Carlson > Informix DBA > WHSmith USA > > #include std_disclaimer.h /* These are my opinions, not my company's > opinion */
Red Valsen wrote: > > What are the most common Informix-related errors that a user may > encounter for an OLTP application? By far the most common problems are lock contention caused by PAGE level locking (the default for new tables) rather than ROW level locking, and poorly designed applications that hold too many locks too long. Conversely, applications written without SET LOCK MODE TO WAIT either do not recover from briefly locked rows or contain massive amounts of manual recovery code. Another problem is deadlock rollbacks caused by applications that access related tables/rows in different orders resulting in deadlocks which the engine detects and causes one of the offending transactions to rollback. Art S. Kagel
Red Valsen wrote: > > What are the most likely errors that I would encounter as a user sitting > down to an OLTP application (e.g., a personnel/benefits system, order entry > system, retail transactions system) which are related to the application's > use of the DBMS? For example, I try to update a field on which a check > constraint has been placed, but which may not be trapped first by the GUI > portion of the application; or I attempt to add an entry for new customer > "Red Valsen," but the record already exists. > I get it . . . I would say that record locking would be high on my list. I don't want to reignite the page- vs. row-level locking debate, but concurrency is something to look at. I'd recommend row-level locking along with "SET LOCK MODE TO WAIT xx", where xx is an acceptable number of seconds to wait on a lock before returning an error. Deadlocks are possible also, but I haven't seen enough of them to worry about. > We are attempting to write a generic Java class which adequately handles > most SQL-related errors, including giving users non-cryptic (or even > helpful) error messages. > Wow . . . . a first! 8-) -- John Carlson Informix DBA WHSmith USA #include std_disclaimer.h /* These are my opinions, not my company's opinion */