Document Type | Troubleshooting
Category | Administration
Applicable Product Version | T6, T7
Document Number | TADTS075
Issue
An issue occurs where the following log is excessively accumulated in the log.
THROW. ec=ERROR_TX_CANT_BEGIN_TX(-21001) [Unable to start transaction. ] (csr_id:47223) [ tx.c:860:tx_bind_slot]
Cause
This occurs when the number of UNDO SEGMENTS is insufficient compared to the number of sessions performing concurrent TRANSACTIONS.
Solutions
Increase the value of the parameter (USGMT_ONLINE_MAX) that determines the number of UNDO SEGMENTS.
It is a DYNAMIC PARAMETER and can be applied without restarting.
SQL> alter system set USGMT_ONLINE_MAX=1500;
NoteFrom Tibero7 version and above, the hidden parameter (_USGMT_ONLINE_MAX) has been changed to the public parameter (USGMT_ONLINE_MAX).Set it to 1.5 times the number of sessions performing concurrent TRANSACTIONS.