FFDC dump output description

This information describes the data areas and types of information available in a first-failure data capture (FFDC) dump output.

Like the figure in the A first-failure data capture dump, the following data areas and types of information are available in the FFDC dump output:

Each FFDC dump output will differ in content, but the format is generally the same. An index (I) is provided to help you understand the content and location of each section of data.
Each section of data is identified by SPACE and a number; for example: SPACE- … 01. The sections of data present in your dump output are dependent on the operation and its progress at the time of failure.
Each section of data is given a name; for example SQCA. SQCA is the section name for data from the DB2^® UDB Query Manager and SQL Development Kit SQL diagnostic area. To locate the SQL diagnostic area data, find SQCA in the index (I). In the sample dump index, SQCA is shown to be in data section 10 (10=SQCA). To view the SQL diagnostic area data, go to the SPACE- 10 heading.
There are two basic classes of modules that can be dumped:
- Application requester (AR) modules
- Application server (AS) modules
The sample dump output is typical of a dump from an AR module. AR dump outputs typically have a fixed number of data sections identified in the index. (For example, in the sample dump output SPACE- 01 through 16 are listed.) In addition, they have a variable number of other data sections. These sections are not included in the index. (For example, in the sample dump output, SPACE- 17 through 25 are not listed in the index.)

Application server dump output is usually simpler because they consist only of a fixed number of data sections, all of which are identified in the index.
There are index entries for all data sections whether the data section actually exists in the current dump output or not. For example, in the sample dump output, there is no SPACE- 08. In the index, 08 equals QDTA (query data). The absence of SPACE- 08 means that no query data was returned, so none could be dumped.
In the sample dump output, the last entry in the index is "(REST IS CCB, PCBS, SAT, PMAP, RCVB, PER CCB)". This entry means that SPACE- 17 and upward contain one or more communications control blocks (CCB), each containing:
- Zero, one, or more path control blocks (SPCB); there is normally just one.
- Exchange server attributes control block (EXCB)
- Parser map space
- Receive buffer for the communications control block
The data section number is increment by one from 17 onward as each control block is dumped. For example, in the sample dump output, data sections SPACE- 17 through SPACE- 21 are for the first data control block dumped (CCB 1), while data sections SPACE- 22 through SPACE- 25 are for the second data control block dumped (CCB 2), as shown here:
17

CCB (Eyecatcher is :'SCCB:'. For an application server module, the eyecatcher is :'TCCB:'.)

18

PCB for CCB 1 (Eyecatcher is :'SPBC:'.)

19

SAT for CCB 1 (Eyecatcher is :'EXCB:'.)

20

PMAP for CCB 1 (No eyecatcher.)

21

RCVB for CCB 1 (No eyecatcher.)

22

CCB 2 (Eyecatcher is :'SCCB:'.)

--

(No PCB for CCB 2 because the conversation is not active.)

23

SAT for CCB 2 (Eyecatcher is :'EXCB:'.)

24

PMAP for CCB 2 (No eyecatcher.)

25

RCVB for CCB 2 (No eyecatcher.)

A

Name and release information of the server on which the dump was taken.

B

Name of job that created the dump output.

C

Name of module in the operating system suspected of failure.

D

Name of module that detected the failure.

Symptom string-contents:

E: Message identifier.
F: Name of module suspected of causing the FFDC dump.
G: Return code (RC), identifying the point of failure.

The first digit after RC indicates the number of dump files associated with this failure. There can be multiple dump files depending on the number of conversations that were allocated. In the sample dump output, the digit is "1", indicating that this is the first (and possible the only) dump file associated with this failure.

You might have four digits (not zeros) at the rightmost end of the return code that indicate the type of error.

The possible codes for errors detected by the AR are:
0001

Failure occurred in connecting to the remote database

0002

More-to-receive indicator was on when it should not have been

0003

AR detected an unrecognized object in the data stream received from the AS

0097

Error detected by the AR DDM communications manager

0098

Conversation protocol error detected by the DDM component of the AR

0099

Function check
The possible codes for errors detected by the AS are:
0099

Function check

4415

Conversational protocol error

4458

Agent permanent error

4459

Resource limit reached

4684

Data stream syntax not valid

4688

Command not supported

4689

Parameter not supported

4690

Value not supported

4691

Object not supported

4692

Command check

8706

Query not open

8708

Remote database not accessed

8711

Remote database previously accessed

8713

Package bind process active

8714

FDO:CA descriptor is not valid

8717

Abnormal end of unit of work

8718

Data and/or descriptor does not match

8719

Query previously opened

8722

Open query failure

8730

Remote database not available

H

SPACE- number identifying a section of data. The number is related to a data section name by the index. Data section names are defined under I below.

I

An index and definition of SPACE- numbers (defined in H) to help you understand the content and location of each section of data. The order of the different data sections might vary between dump output from different modules. The meaning of the data section names are:

AFT: DDM active file table, containing all conversation information.
ARDB: Access remote database control block, containing the AR and AS connection information.
ARDP: ARD program parameters at start of user space.
BDTA: Buffer processing communications area (BPCA) and associated data record from SELECT INTO statement.
Bind: SQL bind template
BPCA: BPCA structure (without data records)
DATA: Data records associated with the BPCA. It is possible that the records in this section do not reflect the total BPCA buffer contents. Already-processed records might not be included.
DOFF: Offset within query data stream (QRYDTA) where the error was detected.
EICB: Error information control block
EMSG: Error message associated with a function check or DDM communications manager error.
FCT: DDM function code point (2 bytes)
FDOB: FDO:CA descriptor input to the parser in an execute operation.
FDTA: FDO:CA data structure consisting of:
- A four-byte field defining the length of the FDO:CA data stream (FDODTA)
- The FDODTA
HDRS: Communications manager command header stack.
IFMT: ARD program input format.
INDA: Input SQLDA containing user-defined SQLDA for insert, select, delete, update, open, and execute operations.
INDX: The index that maps the data section name to the data section SPACE- code. Not all of the entries in the index have a corresponding data section. The dump data is based on the error that occurs and the progress of the operation at the time of the error. A maximum of 32 entries can be dumped in one spooled file.
INST: SQL statement
ITKN: Interrupt token.
OFMT: ARD program output format.
PKGN: Input package name, consistency token and section number.
PMAP: Parser map in an AS dump output.
PRMS: DDM module input or output parameter structure.
PSOP: Input parser options.
QDTA: Query data structure consisting of:
- A four-byte field defining the length of the query data stream (QRYDTA)
- The QRYDTA
RCVB: Received data stream. The contents depend on the following conditions:
- If the dump occurs on the application server, the section contains the DDM request data that was sent from the application requester.
- If the dump occurs on the application requester, the section contains the DDM reply data that was sent from the application server. If this section is not present, it is possible the received data might be found in the receive buffer in the variable part of the dump.
RDBD: Relational database directory.
RFMT: Record format structure.
RMTI: Remote location information in the commitment control block.
RTDA: Returned SQLDA (from ARD program).
SMCB: DDM source master control block, containing pointers to other DDM connection control blocks and internal DDM control blocks.
SNDB: Send data stream. The contents depend on the following conditions:
- If the dump occurs on the application requester, the buffer contains the DDM request that was sent to the application server or that was being prepared to send.
  Note the four bytes of zeros that are at the beginning of SPACE- 05 in the example. When zeros are present, they are not part of the data stream. They represent space in the buffer that is used only in the case that a DDM large object has to be sent with a DDM request. The DDM request stream is shifted left four bytes in that case.
- If the dump occurs on the application server, the buffer contains the DDM reply data that was being prepared to send to the application requester.
SQCA: Output SQL diagnostic area being returned to the user.
SQDA: SQLDA built by the FDO:CA parser.
TBNM: Input remote database table name.
TMCB: Target main control block.
TSLK: Target or source connection control block, containing pointers to the DDM active file table and other internal DDM control blocks.
VARS: Local variables for the module being dumped.
WRCA: Warning SQLCA returned only for an open operation (OPNQRYRM).
XSAT: Exchange server attributes control block.
Remainder: Multiple conversation control blocks for all the DDM conversations for the job at the time of the error. Each conversation control block contains the following items:
- Path control blocks, containing information about an established conversation. There can be multiple path control blocks for one conversation control block.
- One exchange server information control block, containing information about the application requester and application server.
- One DDM parser map area, containing the locations and values for all the DDM commands, objects, and replies.
- One receive buffer, containing the requested data stream received by the application server.
The data section number is incremented by one as each control block is dumped.

J

The eyecatcher area. Information identifying the type of data in some of the areas that were dumped.

K

The logical unit of work identifier (LUWID) for the conversation in progress at the time of the failure can be found in the access RDB control block. This data area is identified by the string 'ARDB' in the FFDC index. In this example, it is in SPACE- 07. The LUWID begins at offset 180. The network identifier (NETID) is APPC. A period separates it from the logical unit (LU) name, RCHAS378, which follows. Following the LU name is the six-byte LUW instance number X'A7CCA7541372'.