Recovery Log Pinning (TSM)

Slow and/or hung backup sessions can "pin" the recovery log, where incremental database backups fail to free any log space. The process or session that has the log pinned may be identified using the following undocumented dsmadmc command:

tsm: TSM>show logpin
Dirty page Lsn=3918732.214.3813, Last DB backup Lsn=3918669.212.3866, Transaction table
Lsn=3918727.169.961, Running DB backup Lsn=0.0.0, Log truncation Lsn=3918669.212.3866

Lsn=3918669.212.3866, Owner=DB, Length=56
Type=Update, Flags=C2, Action=AllocPage, Page=6705152, Tsn=0:191592766, PrevLsn=3918669.212.1355,
UndoNextLsn=0.0.0, UpdtLsn=3918669.192.3520 ===>
Bit Offset = 186
The recovery log is pinned by the last data base backup.  Space will not be freed until data base
backup is run again.

Typical actlog log entries for this condition include:

ANR4556W Attention: the database backup operation did not free sufficient recovery log space to
lower utilization below the database backup trigger.
The recovery log size may need to be increased or the database backup trigger parameters may need
to be adjusted.

And if restarting the TSM server dsmserv with a full log:

ANR7823S Internal error LOGSEG871 detected.
ANR9999D Trace-back of called functions:
ANR9999D   0x000000010006861C  pkAbort
ANR9999D   0x00000001005B4540  LogAllocSegment
ANR9999D   0x00000001005AEF1C  ForceLogPages
ANR9999D   0x00000001005ACF54  LogWriterThread
ANR9999D   0x000000010006C154  StartThread
ANR9999D   0xFFFFFFFF7EF203B0  *UNKNOWN*
ANR9999D   0x000000010006C034  StartThread

See Also

• IBM Technote Preventing Sessions From Pinning the Recovery Log.