Avoid using same view multiple times inside oracle procedures - oracle

Question

I am using a view named V_ENT_MSG in my oracle procedure "TEST PROC" as shown below. The same view is used in multiple places inside the procedure and the procedure execution time is very high. The view returns more than 5 Million records every time. How can I improve procedure execution time. [ Note that I cannot change the view V_ENT_MSG].
create or replace PROCEDURE "TESTPROC"
AS
BEGIN
INSERT
INTO OUTBOUND1
(
DELIVERY_EVENT_ID,
MESSAGE_ID
)
SELECT
V2.DELIVERY_EVENT_ID,PS.MESSAGE_ID
FROM V_ENT_MSG V2,
R_SOURCE PS
WHERE V2.primary_source = PS.SOURCE;
COMMIT;
INSERT
INTO OUTBOUND2
(
DELIVERY_EVENT_ID,
MESSAGE_BODY
)
SELECT
V2.DELIVERY_EVENT_ID,PS2.MESSAGE_BODY
FROM V_ENT_MSG V2,
R_SOURCE2 PS2
WHERE V2.primary_source = PS2.SOURCE;
COMMIT;
INSERT
INTO OUTBOUND3
(
DELIVERY_EVENT_ID,
SUBJECT
)
SELECT
V2.DELIVERY_EVENT_ID,PS3.SUBJECT
FROM V_ENT_MSG V2,
R_SOURCE3 PS3
WHERE V2.primary_source = PS3.SOURCE;
COMMIT;
END TESTPROC;

Answer 1

You may be able to rewrite this as a multitable insert. To do this, you need to:
(Outer) join the view to each table
insert all the result of this query
Use the when clause to control which rows go in which tables
Which looks something like:
insert all
when ps.source is not null then
into outbound1 ( delivery_event_id, message_id )
values ( delivery_event_id, message_id )
when ps2.source is not null then
into outbound2 ( delivery_event_id, message_body )
values ( delivery_event_id, message_body )
when ps3.source is not null then
into outbound3 ( delivery_event_id, subject )
values ( delivery_event_id, subject )
select v.delivery_event_id,ps3.subject
from v_ent_msg v
left join r_source ps
on v.primary_source = ps.source
left join r_source2 ps2
on v.primary_source = ps2.source
left join r_source3 ps3
on v.primary_source = ps3.source;
This assumes that each primary_source joins to at most one row in r_sourceX. If it's 1:M and each value of primary_source can join to a different number of rows in each of the other tables it gets trickier.
You'll need to assign a row_number for each source value in each r_sourceX table and only insert those rows where this is one.

Answer 2

Additionally whether you have opted for GTT as suggested by #Littlefoot or not ,you can still use this approach.
How about leveraging INSERT ALL with WITH clause to achieve the same ,
INSERT ALL
/* inserting to OUTBOUND1 based on table_name = R_SOURCE defined during union */
WHEN table_name = 'R_SOURCE' THEN
INTO outbound1(delivery_event_id, message_id)
VALUES(delivery_event_id, message_type)
/* inserting to OUTBOUND2 based on table_name = R_SOURCE2 defined during union */
WHEN table_name = 'R_SOURCE2' THEN
INTO outbound2(delivery_event_id, message_body)
VALUES (delivery_event_id, message_type)
/* inserting to OUTBOUND3 based on table_name = R_SOURC3 defined during union */
WHEN table_name = 'R_SOURCE3' THEN
INTO outbound3(delivery_event_id, subject)
VALUES (delivery_event_id, message_type)
WITH ent_msg
AS
(SELECT v2.delivery_event_id,v2.primary_source
FROM v_ent_msg v2),
src_data
AS
( SELECT v2.delivery_event_id delivery_event_id,ps.message_id message_type,'R_SOURCE' table_name
FROM r_source ps
JOIN ent_msg v2
ON v2.primary_source = ps.source
UNION ALL
SELECT v2.delivery_event_id,ps2.message_body,'R_SOURCE2' table_name
FROM r_source2 ps2
JOIN ent_msg v2
ON v2.primary_source = ps2.source
UNION ALL
SELECT v2.delivery_event_id,ps3.subject,'R_SOURCE3' table_name
FROM r_source3 ps3
JOIN ent_msg v2
ON v2.primary_source = ps3.source
)
SELECT delivery_event_id,message_type,table_name
FROM src_data
I couldn't validate SQL because of tables are missing.
There are other ways too in case of performance issue where we can go for BULK COLLECT with LIMIT. I am not aware of the data set you are dealing with.
Hope this guides you proceeding with your question.