Connect By Prior - Performance and Missing Parent

Question

I have to say right off the top that I'm not a SQL expert by any means so please be gentle. :)
I have a query that runs through a Bill Of Materials that works except for two things:
1. It is horribly slow - 60-90 seconds to return under 300 rows.
2. It doesn't show the parent node.
I'm looking into indexes now, so I'm not sure if there's an issue there or not. As far as #2 goes, there are two tables that are involved: BOM_STRUCTURES_B and BOM_COMPONENTS_B. Every item below the parent node has a BOM_COMPONENTS_B record. If a BOM_COMPONENT is a parent to other components, there is a BOM_STRUCTURES_B record for that. (In other words, everything that is a parent has a BOM_STRUCTURES_B record, and all the children have a BOM_COMPONENTS_B record that point to the parent - BOM_STRUCTURES_B). The only exception to this is the parent node, which only has a BOM_STRUCTURES_B record (it is NOT a child, so there is no BOM_COMPONENTS_B record). I've added a "UNION" to the bottom of the script below, but it changes my sort order completely.
Here's my script:
select bbm.assembly_item_id,
bic.component_item_id Component ,
msi.segment1 Name,
msi.description Description,
bic.component_quantity Quantity,
lpad( ' ', level*2 ) || level MyLevel
from bom_structures_b bbm
,bom_components_b bic
, mtl_system_items msi
where bbm.bill_Sequence_id = bic.bill_sequence_id
and msi.inventory_item_id = bic.component_item_id
and msi.organization_id = bbm.organization_id
start with bbm.assembly_item_id = 271962
and bbm.organization_id = 85
connect by prior bic.component_item_id = bbm.assembly_item_id;
I've hard-coded "start with bbm.assembly_item_id = 271962", as it is the root node of a tree (BOM).
Here's my structure, with extra fields clipped out:
DBMS_METADATA.GET_DDL('TABLE','BOM_STRUCTURES_B','BOM')
CREATE TABLE "BOM"."BOM_STRUCTURES_B"
( "ASSEMBLY_ITEM_ID" NUMBER,
"ORGANIZATION_ID" NUMBER NOT NULL ENABLE,
"COMMON_BILL_SEQUENCE_ID" NUMBER NOT NULL ENABLE,
) PCTFREE 20 PCTUSED 80 INITRANS 10 MAXTRANS 255 NOCOMPRESS LOGGING
STORAGE(INITIAL 131072 NEXT 131072 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 4 FREELIST GROUPS 4 BUFFER_POOL DEFAULT)
TABLESPACE "APPS_TS_TX_DATA"
DBMS_METADATA.GET_DDL('TABLE','BOM_COMPONENTS_B','BOM')
CREATE TABLE "BOM"."BOM_COMPONENTS_B"
("COMPONENT_ITEM_ID" NUMBER,
"BILL_SEQUENCE_ID" NUMBER NOT NULL ENABLE,
"PARENT_BILL_SEQ_ID" NUMBER,
) PCTFREE 35 PCTUSED 50 INITRANS 10 MAXTRANS 255 NOCOMPRESS LOGGING
STORAGE(INITIAL 131072 NEXT 131072 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 4 FREELIST GROUPS 4 BUFFER_POOL DEFAULT)
TABLESPACE "APPS_TS_TX_DATA"
DBMS_METADATA.GET_DDL('TABLE','MTL_SYSTEM_ITEMS_B','INV')
CREATE TABLE "INV"."MTL_SYSTEM_ITEMS_B"
( "INVENTORY_ITEM_ID" NUMBER NOT NULL ENABLE,
"ORGANIZATION_ID" NUMBER NOT NULL ENABLE,
"DESCRIPTION" VARCHAR2(240),
) PCTFREE 10 PCTUSED 70 INITRANS 10 MAXTRANS 255 NOCOMPRESS LOGGING
STORAGE(INITIAL 131072 NEXT 131072 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 4 FREELIST GROUPS 4 BUFFER_POOL DEFAULT)
TABLESPACE "APPS_TS_TX_DATA"
The relationship between the tables is:
A BOM_STRUCTURES_B has many BOM_COMPONENTS_B where BOM_COMPONENTS_B.PARENT_BILL_SEQ_ID = BOM_STRUCTURES_B.BILL_SEQUENCE_ID. Both BOM_STRUCTURES_B.ASSEMBLY_ITEM_ID and BOM_COMPONENTS_B.COMPONENT_ITEM_ID are related to a single MTL_SYSTEM_ITEMS_B.INVENTORY_ITEM_ID.
Thanks to anyone who can help with this horrible problem I've been fighting with for much too long! :)
Thank you!
Steve

Answer 1

Due to an error in the otn forums (*), this got posted to the wrong forum, sorry for that, I'll repost in the correct one.
*) For the forum admins: I was browsing the SQL/PLSQL forum, clicked on 'new message', got the login prompt, logged in, and apparently this got me to the application server forum for some reason.