> I have this SQL statement:
>
> SELECT A.KURZ_LIST,A.KOMBINOVAT
> FROM KOMBINACIE A
> LEFT JOIN TIKETY2 B ON (B.KURZ_LIST=A.KURZ_LIST)
> WHERE (A.KURZ_LIST=19954 OR B.TIKET=9251001)
> ;
>
> Plan:
> PLAN JOIN (A NATURAL,B INDEX (IDX_TIKETY2_KURZ_LIST))

Of course. You are using Left Outer join, but rows from left table can't be
simply restricted using index because your Where clause contains ... OR B.TIKET=...,
i.e. the query can return more rows from left table than just those selected by "A.KURZ_LIST=19954"

Ivan
http://www.volny.cz/iprenosil/interbase

>
> DDLs:
>
> CREATE TABLE TIKETY2 (JEDIN INTEGER,KURZ_LIST INTEGER,TIKET INTEGER, ...);
> ALTER TABLE TIKETY2 ADD CONSTRAINT PK_TIKETY2 PRIMARY KEY (JEDIN);
> CREATE INDEX IDX_TIKETY2_KURZ_LIST ON TIKETY2 (KURZ_LIST);
> CREATE UNIQUE INDEX TIKETY2_STAVKA ON TIKETY2 (TIKET, KURZ_LIST);
>
> CREATE TABLE KOMBINACIE (JEDIN INTEGER NOT NULL,KOMBINOVAT INTEGER,KURZ_LIST INTEGER);
> ALTER TABLE KOMBINACIE ADD CONSTRAINT PK_KOMBINACIE PRIMARY KEY (JEDIN);
> CREATE INDEX IDX_KOMBINACIE_KOMBINOVAT ON KOMBINACIE (KOMBINOVAT);
> CREATE INDEX IDX_KOMBINACIE_KURZ_LIST ON KOMBINACIE (KURZ_LIST);
>
> Record count: TIKETY2>90000 and KOMBINACIE>9000
>
> But execute time is too slow, but if I use (this statement not return
> right result set):
>
> SELECT A.KURZ_LIST,A.KOMBINOVAT
> FROM KOMBINACIE A
> LEFT JOIN TIKETY2 B ON (B.KURZ_LIST=A.KURZ_LIST)
> WHERE (A.KURZ_LIST=19954 AND B.TIKET=9251001)
> ;
>
> is plan PLAN JOIN (A INDEX (IDX_KOMBINACIE_KURZ_LIST),B INDEX (IDX_TIKETY2_KURZ_LIST))
>
> and result set is returned immediately.
>
> How to optimize this ?