Stephane,

> => time taken 2ms
> PLAN (GEO_PLACE INDEX (RDB$PRIMARY24))


> => time taken 1230ms
> PLAN (GEO_PLACE INDEX (RDB$PRIMARY24))


> => time taken 80ms
> PLAN (GEO_PLACE INDEX (RDB$PRIMARY24))
>
>
> Why with the like clause it's soo long ??

The PLAN does not explain all aspect of how the engine is
operating/evaluating a condition, it only indicates which index is being
used.

It is most likely that the LIKE command needed to read more index pages
in order to resolve the result.

Your 2nd LIKE statement was faster simply because it used the same pages
which were loaded the computer memory/cache from the first query, so it
ran faster.

The full details of the number of disk reads, disk fetches are really
required to explain the performance difference.


Sean