Freitag Feb. 03, 2012
Oracle - Statements ohne Bindungsvariablen
Größere Performanceprobleme bei Oracle können sich ergeben, wenn man nicht konsequent Queries mit Bindungsvariablen einsetzt. Um mal schnell rauszufinden, welche davon so laufen, kann man folgende Statements nutzen:
create table t1 as select sql_text from v$sqlarea;
alter table t1 add sql_text_wo_constants varchar2(1000);
create or replace function
remove_constants( p_query in varchar2 ) return varchar2
as
l_query long;
l_char varchar2(1);
l_in_quotes boolean default FALSE;
begin
for i in 1 .. length( p_query )
loop
l_char := substr(p_query,i,1);
if ( l_char = '''' and l_in_quotes )
then
l_in_quotes := FALSE;
elsif ( l_char = '''' and NOT l_in_quotes )
then
l_in_quotes := TRUE;
l_query := l_query || '''#';
end if;
if ( NOT l_in_quotes ) then
l_query := l_query || l_char;
end if;
end loop;
l_query := translate( l_query, '0123456789', '@@@@@@@@@@' );
for i in 0 .. 8 loop
l_query := replace( l_query, lpad('@',10-i,'@'), '@' );
l_query := replace( l_query, lpad(' ',10-i,' '), ' ' );
end loop;
return upper(l_query);
end;
/
update t1 set sql_text_wo_constants = remove_constants(sql_text);
select sql_text_wo_constants, count(*)
from t1
group by sql_text_wo_constants
having count(*) > 100
order by 2
/
alter table t1 add sql_text_wo_constants varchar2(1000);
create or replace function
remove_constants( p_query in varchar2 ) return varchar2
as
l_query long;
l_char varchar2(1);
l_in_quotes boolean default FALSE;
begin
for i in 1 .. length( p_query )
loop
l_char := substr(p_query,i,1);
if ( l_char = '''' and l_in_quotes )
then
l_in_quotes := FALSE;
elsif ( l_char = '''' and NOT l_in_quotes )
then
l_in_quotes := TRUE;
l_query := l_query || '''#';
end if;
if ( NOT l_in_quotes ) then
l_query := l_query || l_char;
end if;
end loop;
l_query := translate( l_query, '0123456789', '@@@@@@@@@@' );
for i in 0 .. 8 loop
l_query := replace( l_query, lpad('@',10-i,'@'), '@' );
l_query := replace( l_query, lpad(' ',10-i,' '), ' ' );
end loop;
return upper(l_query);
end;
/
update t1 set sql_text_wo_constants = remove_constants(sql_text);
select sql_text_wo_constants, count(*)
from t1
group by sql_text_wo_constants
having count(*) > 100
order by 2
/
Posted at 12:33nachm. Feb. 03, 2012 by cetixx in Tipps | Kommentare [0]
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