[Oracle] Where is the In-memory join Group located in memory?

Where is the data dictionary of the In-memory join Group located in memory?

A customer asked if the Join Group was used when using Oracle's In-memory function,
So where are these join Group, located in memory?

According to the results of colleagues ' execution, the following are organized:

1.prepare Test env.
CREATE TABLE T1 as select * from Dba_tables
CREATE TABLE t2 as SELECT * from Dba_tables
Create InMemory join Group T_join (T2 (table_name), T1 (table_name))
Create InMemory join Group T_join1 (T2 (owner), T1 (owner))

ALTER TABLE T1 InMemory
ALTER TABLE T2 InMemory
Alter system set Inmemory_size =300m


==run SQL
SELECT T1.owner,t2.table_name
from T1, T2
WHERE T1.table_name = T2.table_name

==check GD
Select O.object_name table_name, C.column_name column_name, gd.head_address as "GD address"
From User_objects O, user_tab_columns C, V$im_segdict GD
WHERE GD.OBJN = o.object_id
and o.object_name = C.table_name
and gd.column_number = c.column_id;


T1 table_name 000000008A8B10F0
T2 OWNER 000000008a8310f0


Dump the Memory:

==dum SGA Memory
Heap DUMP heap Name= "IMCA_RW" desc=0x60001178 ***<<<<Extent sz=0x1040 alt=336 het=32767 rec=0 flg=0x2 opc=0
Parent= (nil) owner= (nil) nex= (nil) xsz=0x3bfffd0 heap= (nil)
FL2=0XA4, nex= (nil), idx=0, Dsxvers=1, dsxflg=0x0
DSX First ext=0x89800030
DSX Empty ext bytes=0 subheap RC link=0x898000a0,0x898000a0
PDB id=1, SRC PDB id=1
EXTENT 0 addr=0x89800030
Chunk 089800040 sz= Perm "Perm" alo=112
Dump of memory from 0x0000000089800040 to 0x00000000898000b0
.............
Chunk 08a7e10d8 sz= 46137368 freeable "Cimadrv"
Dump of memory from 0x000000008a7e10d8 to 0x000000008d3e10f0 ***<<<<<this chunk cover these address.

Repeat 3489 Times
08a8b10f0 0a0a0a0a 00011e8e 00000001 00000836 [.....] 6 ...]
08a8b1100 8a8c10f0 00000000 00000000 00000000 [.........]
08a8b1110 00000000 00000000 00000000 00000000 [.........]

Repeat 3489 Times
08a8310f0 0a0a0a0a 00011e8f 00000000 00000014 [.........]
08a831100 8a8410f0 00000000 00000000 00000000 [.........]
08a831110 00000000 00000000 00000000 00000000 [.........]

It can be concluded that it is located in memory's Clumn store.

[Oracle] Where is the In-memory join Group located in memory?