Format of the history log

A database file is used to store the messages sent to a log message queue on the system. Because all records in a physical file have the same length and messages sent to a log have different lengths, the messages can span more than one record.

Each record for a message has three fields:

System date and time (a character field of length 8). This is an internal field. The converted date and time also are in the message.
Record number (a 2-byte field). For example, the field contains hex 0001 for the first record, hex 0002 for the second record, and so on.
Data (a character field of length 132).

The third field (data) of the first record has the following format:

Contents	Type	Length	Positions in Record
Job name	Character	26	11-36
Converted date and time¹	Character	13	37-49
Message ID	Character	7	50-56
Message file name	Character	10	57-66
Library name	Character	10	67-76
Message type²	Character	2	77-78
Severity code	Character	2	79-80
Sending program name³	Character	12	81-92
Sending program instruction number⁴	Character	4	93-96
Receiving program name³	Character	10	97-106
Receiving program instruction number⁴	Character	4	107-110
Message text length	Binary	2	111-112
Message data length	Binary	2	113-114
Coded character set identifier (CCSID) for text or data⁵	Binary	4	115-118
Sending user profile	Character	10	119–128
Reserved	Character	14	129-142
: ¹ The format is: `cyymmddhhmmss` where: `c` Is the century digit (c=0 if yy ≥ 40, c = 1 if yy < 40) `yymmdd` Is the year, month, and day that the message is sent `hhmmss` Is the hour, minute, and second that the message is sent ² This has the same value as the RTNTYPE parameter on the Receive Message (RCVMSG) command. ³ If the sender or receiver is an ILE procedure, the entry in the history log contains only the ILE program name. The module name and procedure name are not included in the history log. ⁴ If the sender or receiver is an ILE procedure, the sending or receiving instruction number is 0. ⁵ This CCSID applies only to the message data that is defined as *CCHAR data if the message is a stored message. The rest of the message data can be considered 65 535. Otherwise, this is the CCSID of the immediate message.

The third field (data) of the remaining records has the following format:

Contents	Type	Length
Message	Character	Variable¹
Message data	Character	Variable²
: ¹ This length is specified in the first record (positions 111 and 112) and cannot exceed 132. ² This length is specified in the first record (positions 113 and 114).

A message is never split when a new version of a log is started. The first and last records of a message are always in the same QHST log version file.