PERFORMANCE BAD WHEN CURSORS ARE USED WITHIN PL/SQL BLOCKS

Question

There are poor database performance at Oracle 10g
For some cursor selects, the performance is under Oracle 10g
significant slower than under Oracle 9i.On a test system (Oracle 9) the
problem does not reproduce, on the 10g system however always.
The simple execution of the base select statement was on both
databases in roughly of the same speed. If however a cursor was defined and
those executed within a PL/SQL block (without involving the user interface),
then the time behavior was in accordance with the observed behavior
behavior on the user interface.
By adding of the hint first_rows on both machines a
similar (fast) time behavior can be achieved.
Conclusion: Something in the (Optimizer) settings of the Oracle-10
databases must be fundamentally different than that of Oracle 9. Or Oracle
10 has a real problem. The analysis and solution of this general
problem seems to me more reasonable than the solution of individual performance
problems.
can you help me, many thanks

Answer 1

Hello, thanks for the explanatory notes.
Here are the concerned Script. The only difference is the Hint (with Hint = good püerformance; without Hint = bad performance)
DECLARE
b BOOLEAN;
BEGIN
b := plogin.batch_login('**', '****', 717, FALSE);
prost.reload_context;
END;
DECLARE
l_ma_kuerzel VARCHAR2(100) DEFAULT NULL;
l_sta_id mitarbeiter_historie.sta_id%TYPE;
l_org_id organisationseinheit.org_id%TYPE;
l_pv_like mitarbeiter.ma_name%TYPE;
l_typ_id typ.typ_id%TYPE;
l_mihi_beginn VARCHAR2(40);
l_ma_ausgeschieden VARCHAR2(40);
l_ma_ldap mitarbeiter.ma_ldap%TYPE;
l_smodify_form VARCHAR2(80);
l_sform_typ VARCHAR2(80);
l_sheader VARCHAR2(200);
l_nurlsource NUMBER;
l_nurldestination prosturl.pur_id%type;
l_ma_like VARCHAR2(100) DEFAULT NULL;
l_nma_typ NUMBER;
l_bshow BOOLEAN;
l_counter NUMBER DEFAULT 0;
cursor ma_list_not_all_detail(
p_ma_like IN VARCHAR2 DEFAULT NULL,
p_ma_kuerzel IN VARCHAR2 DEFAULT NULL,
p_sta_id IN VARCHAR2 DEFAULT NULL,
p_org_id IN VARCHAR2 DEFAULT NULL,
p_typ_id IN VARCHAR2 DEFAULT NULL,
p_mihi_beginn IN VARCHAR2 DEFAULT NULL,
p_pv_like IN VARCHAR2 DEFAULT NULL,
p_ma_ausgeschieden IN VARCHAR2 DEFAULT NULL,
p_ma_ldap IN VARCHAR2 DEFAULT NULL
) IS
SELECT /*+ first_rows */
ma.ma_id ma_id
, view_fkt.display_ma(mihi.typ_id_mt
, view_fkt.cat_maname(ma.ma_name
, ma.ma_zusatz
, ma.ma_titel
, ma.ma_vorname)) name
, view_fkt.display_ma(mihi.typ_id_mt,ma.ma_kuerzel) ma_kuerzel
, typ.typ_value mt_kuerzel
, substr(org.typ_id,4,length(org.typ_id)) || ' ' || org.org_name||' ('||org.org_ktr||')' org_name
, to_char(mihi.mihi_beginn, 'dd.mm.yyyy') beginn
, decode(pv.ma_name ||' '|| pv.ma_titel ||' '|| pv.ma_vorname
, ' ',prost_cons.t_blank
, pv.ma_name||', '||pv.ma_titel||' '||pv.ma_vorname) pv_kuerzel
, mihi.sta_id sta_id
, nvl(to_char(ma.ma_ausgeschieden,'dd.mm.yyyy'), ' ') ausgeschieden
, nvl(to_char(mihi.mihi_wochenarbeitszeit,'90D00'),' ') wochenarbeitszeit
, nvl(to_char(mihi.mihi_taz_mo,'90D00'),' ') taz_mo
, nvl(to_char(mihi.mihi_taz_di,'90D00'),' ') taz_di
, nvl(to_char(mihi.mihi_taz_mi,'90D00'),' ') taz_mi
, nvl(to_char(mihi.mihi_taz_do,'90D00'),' ') taz_do
, nvl(to_char(mihi.mihi_taz_fr,'90D00'),' ') taz_fr
, nvl(to_char(mihi.mihi_taz_sa,'90D00'),' ') taz_sa
, nvl(to_char(mihi.mihi_taz_so,'90D00'),' ') taz_so
, nvl(ma.ma_ldap, ' ') ma_ldap
, mihi.mihi_beginn mihi_beginn
, mihi.mihi_order_no mihi_order_no
, mihi.mihi_order_pos mihi_order_pos
FROM organisationseinheit org
, typ typ
, mitarbeiter pv
, mitarbeiter ma
, v$mihi_id mid
, mitarbeiter_historie mihi
, v$access_orgs_th_t th
WHERE mihi.org_id = th.org_id
AND mid.mihi_id = mihi.mihi_id
AND ma.ma_id = mid.ma_id
AND ma.ma_delete = 'n'
AND ma.ma_virtualitaet = 'N'
AND (p_ma_like IS NULL
OR ma.ma_name LIKE p_ma_like)
AND (p_ma_kuerzel IS NULL
OR ma.ma_kuerzel LIKE p_ma_kuerzel)
AND (p_sta_id IS NULL
OR mihi.sta_id = p_sta_id)
AND (p_org_id IS NULL
OR org.org_id = p_org_id)
AND (p_typ_id IS NULL
OR typ.typ_id = p_typ_id)
AND mihi_beginn >= nvl(p_mihi_beginn,to_date('01.01.1960','dd.mm.yyyy'))
AND (p_pv_like IS NULL
OR pv.ma_name LIKE p_pv_like)
AND (ma.ma_ausgeschieden >= nvl(p_ma_ausgeschieden,to_date('01.01.1960','dd.mm.yyyy'))
AND ma.ma_ausgeschieden - 1 < nvl(p_ma_ausgeschieden,to_date('01.01.1960','dd.mm.yyyy'))
OR p_ma_ausgeschieden IS NULL)
AND (p_ma_ldap IS NULL
OR ma.ma_ldap LIKE p_ma_ldap)
AND pv.ma_id (+)= mihi.ma_id_pv
AND org.org_id (+)= mihi.org_id
AND typ.typ_id = mihi.typ_id_mt
ORDER BY upper(ma.ma_name), upper(ma.ma_vorname);
l_result ma_list_not_all_detail%ROWTYPE;
BEGIN
l_nMA_Typ := pmitarbeiter.cn_Incomplete_Ma;
l_ma_like := NULL;
l_ma_kuerzel := NULL;
l_sta_id := NULL;
l_org_id := 'KST0000421301';
l_typ_id := NULL;
l_mihi_beginn := NULL;
l_pv_like := NULL;
l_ma_ausgeschieden := NULL;
l_ma_ldap := NULL;
IF (l_ma_like IS NOT NULL
OR l_ma_kuerzel IS NOT NULL
OR l_sta_id IS NOT NULL
OR l_org_id IS NOT NULL
OR l_typ_id IS NOT NULL
OR l_mihi_beginn IS NOT NULL
OR l_pv_like IS NOT NULL
OR l_ma_ausgeschieden IS NOT NULL
OR l_ma_ldap IS NOT NULL) THEN
-- fuer Mitarbeiter unvollstandig wird ein andere cursor angesprochen
-- um der Mitarbeiter vollstandig zu kriegen soll ein Standort,
-- Arbeitszeitmodel, Bereich und Tagesarbeitszeiten ausgevult wirden
-- Wenn er dan gespeichert wirdt wirden die betriffende velder gespeichert
-- und wirdt das Feld Virtualiteat auf R gesetzt (war N)
l_counter := 0;
dbms_output.put_line(to_char(sysdate, 'sssss'));
FOR j IN ma_List_Not_All_Detail(
l_ma_like,
l_ma_kuerzel,
l_sta_id,
l_org_id,
l_typ_id,
l_mihi_beginn,
l_pv_like,
l_ma_ausgeschieden,
l_ma_ldap
) LOOP
l_counter := l_counter + 1;
dbms_output.put_line(l_counter);
dbms_output.put_line(j.ma_kuerzel);
END LOOP;
dbms_output.put_line(to_char(sysdate, 'sssss'));
END IF;
return;
EXCEPTION
WHEN OTHERS THEN
dbms_output.put_line(sqlerrm);
END;
=============
Thank you