All DB2 common server log records begin with a log manager header.
This header contains information detailing the log record and transaction
information of the log record writer.
Table 95. Log Manager Log Record Header (LogManagerLogRecordHeader)
| Description | Type | Offset (Bytes) |
|---|---|---|
| Length of the entire log record | int | 0(4) |
| Type of log recorda | short | 4(2) |
| Log record general flagb | short | 6(2) |
| Log Sequence Number of the previous log record written by this transaction. It is used to chain log records by transaction. If the value is 0000 0000 0000, this is the first log record written by the transaction. | SQLU_LSNc | 8(6) |
| Unique transaction identifier | SQLU_TIDd | 14(6) |
| Log Sequence Number of the log record for this transaction prior to the log record being compensated. (Note: For compensation and backout free log records only.) | SQLU_LSN | 20(6) |
| Log Sequence Number of the log record for this transaction being compensated. (Note: For propagatable compensation log records only.) | SQLU_LSN | 26(6) |
Total Length for Log Manager Log Record Header:
| ||
|
Definitions and Values a Valid log record types a Datalink manager log record o Backup start
A Normal abort O Backup end
B Backout free p Tablespace roll forward to PIT starts
c MPP coordinator commit P Table quiesce
C Compensation q Tablespace roll forward to PIT ends
D Tablespace rolled forward Q Global pending list
E Local pending list R Redo
F Forget transaction s MPP subordinate commit
g MPP log synchronization S Compensation required
G Load pending list T Partial abort
H Table load delete start U Undo
i Propagate only V Migration begin
I Heuristic abort W Migration end
J Load start X TM prepare
K Load delete start compensation Y Heuristic commit
L Lock description z MPP prepare
M Normal commit Z XA prepare
N Normal
Note: A log record of type 'i' is an informational log record only.
It will be ignored by DB2 during roll forward, roll back,
and crash recovery.
b Log record general flag constants Redo Always 0x0001 Propagatable 0x0002 Conditionally Recoverable 0x0080 c Log Sequence Number (LSN) A unique log record identifier representing the relative byte address
of the log record within the database log.
SQLU_LSN: union { char [6] ;
short [3] ;
}
d Transaction Identifier (TID) A unique log record identifier representing the transaction.
SQLU_TID: union { char [6] ;
short [3] ;
}
| ||