>>>If an idx is faster than a cdx, and the index expression is the same, you must have some kind of data corruption. I suggest that you find the cause of this error instead of trying to fix the consequences of the error.
>>
>>
>>How could that be possible ?
>>I have rebuilt the indexes (cdx) Just before running the tests
>>Is it possible ?????
>
>In that case, no. Maybe you simply should add more RAM? Since a CDX is bigger than an IDX, too little RAM can explain the difference.

Actually, on a table with 5.25 million records,

index on spd_dt to spd_dt.idx

resulted in a .idx file size 66,493KB while

index on spd_dt tag spd_dt of spd_dt.cdx </pre? resulted in a .cdx of size 22,671KB. <pre> index on spd_dt to spd_dt.idx COMPACT

was 22,670KB which is hardly any better than the .cdx. There is more to this than simply the difference in file size. Multiple tags contained in one cdx is supposedly faster to access on a LAN that the same number of .idxs.