Re: fragmentation index

Abdul Lulu wrote: > > Hi Art, > > I need your explanation below, is this correct ? > > When i ran sql script using about 6 tables, where from one of this list > table i'm use is index fragmenting. This sql script it took an hour, but > when i remove the table which use index frament, it only took 5 minute. > > Here is the explanation, why this query took a long time (is this > correct ?) : > > Fragmenting the index is fine if all we want to do is get data that is > part of the index. > > When we include objects that are not part of the index, informix first > goes to the dbspace where the index is and get the index, next it must > scan the dbspace where the data is located and get the data that it is > looking for, causing it to take twice as long. This is true, but I'm not certain that this is your problem. More likely the fragmentation scheme of the index does not match its keys so that all index fragments need to be scanned and the resulting list must be sorted. Please post the schema for the table including the fragmentation schemes for the data and index (dbschema -ss ...) and I, or someone else, will try to diagnose the problem. A SET EXPLAIN output will alos be helpful. Art S. Kagel