Select statement with inner join is taking forever - abap

Question

(....)
DATA: BEGIN OF g00 OCCURS 100,
werks LIKE lqua-werks,
lgort LIKE lqua-lgort,
matnr LIKE lqua-matnr,
charg LIKE lqua-charg,
maktx LIKE makt-maktx,
verme LIKE lqua-verme,
meins LIKE lqua-meins,
dispo LIKE marc-dispo,
END OF g00.
(.....)
CLEAR : g00.
REFRESH : g00.
SELECT lqua~bestq lqua~charg lqua~lgort lqua~lgnum lqua~lgpla
lqua~lgtyp lqua~matnr lqua~meins lqua~verme lqua~werks makt~maktx
makt~matnr makt~spras mara~bismt mara~matnr marc~dispo
marc~matnr marc~werks
INTO (lqua-bestq , lqua-charg , lqua-lgort , lqua-lgnum , lqua-lgpla ,
lqua-lgtyp , lqua-matnr , lqua-meins , lqua-verme , lqua-werks ,
makt-maktx , makt-matnr , makt-spras , mara-bismt , mara-matnr ,
marc-dispo , marc-matnr , marc-werks )
FROM ( lqua
INNER JOIN makt
ON makt~matnr = lqua~matnr
INNER JOIN mara
ON mara~matnr = makt~matnr
INNER JOIN marc
ON marc~werks = lqua~werks
AND marc~matnr = lqua~matnr )
WHERE lqua~bestq IN sbestq
AND lqua~lgnum IN slgnum
AND lqua~lgpla IN slgpla
AND lqua~lgtyp IN slgtyp
AND lqua~matnr IN smatnr
AND lqua~werks IN swerks
AND makt~maktx IN smaktx
AND makt~spras IN sspras
* AND MARA~BISMT IN Sbismt
AND marc~dispo IN sdispo.
MOVE-CORRESPONDING mara TO g00.
MOVE-CORRESPONDING makt TO g00.
MOVE-CORRESPONDING marc TO g00.
MOVE-CORRESPONDING lqua TO g00.
COLLECT g00.
ENDSELECT.
Can anyone help to improve the performance of code above.

Answer 1

Your starting table for the join (LQUA) is not selecting on key or indexed fields, which will always run slower than if you are able to use them.
While there doesn't appear to be a way to join everything on key fields, you might have better luck if you tweak the query to initially pull from MARA (where MATNR is a key field):
FROM ( mara
INNER JOIN makt
ON makt~matnr = mara~matnr
INNER JOIN lqua
ON lqua~matnr = mara~matnr
INNER JOIN marc
ON marc~werks = mara~werks
AND marc~matnr = mara~matnr )...

Answer 2

DO NOT use SELECT END SELECT in the scenario you have described below. Try doing the following :
-> Create a local type with the fields you are picking up select ( lt_yourtype)
( lqua~bestq lqua~charg lqua~lgort lqua~lgnum lqua~lgpla
lqua~lgtyp lqua~matnr lqua~meins lqua~verme lqua~werks makt~maktx
makt~matnr makt~spras mara~bismt mara~matnr marc~dispo
marc~matnr marc~werks )
-> Create work area ( prefer field symbol ) and internal table of the above local type ( lt_yourtype )
-> Replace the given select with :
select lqua~bestq lqua~charg lqua~lgort lqua~lgnum lqua~lgpla
lqua~lgtyp lqua~matnr lqua~meins lqua~verme lqua~werks makt~maktx
makt~matnr makt~spras mara~bismt mara~matnr marc~dispo
marc~matnr marc~werks
into table lt_yourtype
FROM ( lqua
INNER JOIN makt
ON makt~matnr = lqua~matnr
INNER JOIN mara
ON mara~matnr = makt~matnr
INNER JOIN marc
ON marc~werks = lqua~werks
AND marc~matnr = lqua~matnr )
WHERE lqua~bestq IN sbestq
AND lqua~lgnum IN slgnum
AND lqua~lgpla IN slgpla
AND lqua~lgtyp IN slgtyp
AND lqua~matnr IN smatnr
AND lqua~werks IN swerks
AND makt~maktx IN smaktx
AND makt~spras IN sspras
* AND MARA~BISMT IN Sbismt
AND marc~dispo IN sdispo.
loop into lt_yourtype assigning .
*move data to the correct structure and fields here
endloop.