What does "UBABLK" represents in v$transaction view?

Dec 14, 2025 3:50PM

I created a sample table "employees" and inserted around 2.5 Lakh rows into it but didn't commit yet

I checked this transaction using v$transaction as show below -

SQL> @insert _employees_250000.sql

1 row created.

1 row created....1 row created.

1 row created.

SQL> select count(*) from employees;

COUNT(*)

— — —- —-

250000

SQL> select

XIDUSN UNDO_SEG_NO,

XIDSLOT UNDO_SLOT,

UBAFIL UNDO_FILE_NO,

UBABLK UNDO_BLOCK_NO,

STATUS, SES_ADDR

from v$transaction; 2 3 4 5 6 7

UNDO_SEG_NO UNDO_SLOT UNDO_FILE_NO UNDO_BLOCK_NO STATUS SES_ADDR

----------- ---------- ------------ ------------- ---------------- ----------------

21 1 37 290 ACTIVE 000000014C8AB990

here UNDO_BLOCK_NO is 290 so does it mean that all the undo transactions are stored in a single undo block?

Database Administration (MOSC)