記一次解決oracle sql效能瓶頸的問題

先上sql：

select

(select m.album_id from album_r_music am,album m where am.music_id = m.music_id and am.album_id = m.album_id and rownum = 1) album_id,
(select m.album_name from album_r_music am,album m where am.music_id = m.music_id and am.album_id = m.album_id and rownum = 1) album_name,
(select to_char(wm_concat(t.artist_id || ':' ||
t.artist_name))
from music_r_artist mr, artist t
where m.music_id = mr.music_id(+)
and mr.artist_id = t.artist_id
and mr.artist_type = 1) artist_id,
m.music_id,
m.length,
m.music_name,
m.singer_name,
m.rank_num,
m.publish_year,
m.status
from
"tagid != null">
tag ta,
object_r_tag o,
music_r_artist t,
artist_r_type y,
music m
t.artist_id = y
.artist_id
andy.type_id = '1'
and t.music_id = m.music_id
and m.status = '1'
and t.artist_type = 1
"tagid != null">
and m.music_id = o.object_id(+)
and ta.tag_id = o.tag_id
and ta.tag_id = #
and o.object_type = 1

解決辦法是將要關聯的表寫成儲存過程，將music_r_artist t,artist_r_type y,music m這三張需要關聯的表融合成一張大的表，並且將rownum作為一列，加上索引。儲存過程會提前把需要的資料跑出來，這樣我們在查詢的時候去操作musicianas，如下：

create

orreplace
procedure migu_musician_songs
asbegin
execute
immediate
'drop table temp_musicianas';
execute immediate 'create
table temp_musicianas as
select m.*,rownum rn
from music m
where
exists
(select
1from (select music_id
from (select artist_id from artist_r_type where type_id = 1) y,
music_r_artist t
where y.artist_id = t.artist_id) t
where t.music_id = m.music_id
and m.status = 1)';
execute immediate 'rename musicianas to temp_musicianas1';
execute immediate 'rename temp_musicianas to musicianas';
execute immediate '
create index ind_musicianas_rn on musicianas(rn)';
exception
when others then
rollback;
end;

select

(select m.album_id from album_r_music am,album m where am.music_id = m.music_id and am.album_id = m.album_id and rownum = 1) album_id,
(select m.album_name from album_r_music am,album m where am.music_id = m.music_id and am.album_id = m.album_id and rownum = 1) album_name,
(select to_char(wm_concat(t.artist_id || ':' ||
t.artist_name))
from music_r_artist mr, artist t
where m.music_id = mr.music_id(+)
and mr.artist_id = t.artist_id
and mr.artist_type = 1) artist_id,
m.music_id,
m.length,
m.music_name,
m.singer_name,
m.rank_num,
m.publish_year,
m.status
from
"tagid != null">
object_r_tag o,
musicianas m
1= 1
"tagid != null">
and m.music_id = o.object_id(+)
and o.tag_id = #
and o.object_type = 1
and m.rn between $ and $

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