I need to understand something. I'm trying to improve performance on a report. The most selections do not use table keys to acess, so, somebody create some indexes with the idea to make the selection faster. Here is one example:
INTO TABLE t_coep
WHERE bukrs IN s_bukrs
AND gjahr = p_gjahr
AND perio IN r_perio
AND kstar IN s_kstar.
The table COEP has a index with fields bukrs, gjahr, perio e kstar. But, after use ST22 I discover that the database is not using this index. Its use the "normal one".
I know that is not a good programming pratice use select * (I will take out and put only the fields that I want).
Well, somebody com explain to me how the indexes works or have some document about it.
I appreciate any kind of help.