Re: Online Row Level Locking

Mark Lansley writes: >On 11 Feb 1994, Rory Martin wrote: > >> The problem seems to be errors relating to the fact that Online locks >> adjacent rows in a table when a row is locked. Does anyone have any >> suggestions or comments about the best way for the applications to work >> around this? There is considerable activity occurring on the system, and >> the potential for lockouts happening is high. Any thoughts would be >> appreciated. Additional details as soon as I get them (The system is in >> Cincinnati and I am in Wash.DC). Thanks. >> >This is termed "The Twin Problem" by Informix and it caused us a bit of >worry as well! Well, the symptoms Rory describes are a result of what we call "adjacent key locking" which was implemented to fix the "twin problem". >By the way, does anybody know if OnLine 6.00 behaves differently? Yes. In 6.0 a new index structure has been used. This allows us to eliminate adjacent key locks for inserts/updates/deletes. Note that adjacent key locks are still used with a repeatable read isolation level in order to protect the full set (which includes potentially new members) from modification. Dave Kosenko Informix Advanced Services -- Disclaimer: These opinions are not those of Informix Software, Inc. ************************************************************************** "I look back with some satisfaction on what an idiot I was when I was 25, but when I do that, I'm assuming I'm no longer an idiot." - Andy Rooney