HP 3000 Manuals HP 3000 Manuals
Utility Program Operation (contd)
>EXIT
Used to terminate DBRECOV without recovering any databases.
Syntax.
>EXIT
Text Reference.
Chapter 7
>FILE
Routes log records to individual user files, providing the application
program with information about the outcome of recovery; provides a useful
tool for auditing previous entries. One file for each user can be opened
simultaneously by re-entering the >FILE command once for each user, or
all users can be directed to a single file.
Syntax.
>FILE fileref,userref [,rmode,fmode]
Parameters.
fileref is an MPE/iX file reference: filename [/lockword]
[.group[.account]]. This is the destination file
for each user's log records.
userref is a user reference, specifying which user's log
records to copy to this user recovery file. The
format is: username [/ident].account.
The optional identifier, which also must be passed
to DBOPEN as part of the password parameter,
uniquely identifies persons using the same logon.
rmode is for roll-forward recovery only. Directs
recovery system to copy log records associated with
transactions successfully recovered. rmode can
take one of the following values:
0 No records associated with recovered
transactions are copied to the user file.
(Default value.)
1 Log records corresponding to the last
successfully recovered call to DBEND of each
transaction block are copied.
2 The sequence of log records associated with the
last successfully recovered transaction of each
transaction block are copied. In addition, all
DBMEMO log records which immediately follow
this transaction are copied.
3 All log records associated with successfully
recovered transactions for each transaction
block are copied.
fmode directs recovery system to copy log records
associated with transactions that failed to
recover. Used with both roll-forward and roll-back
recovery.
__________________________________________________
CAUTION The (roll-forward) recovery system cannot
guarantee that all records associated with
unsuccessfully recovered transactions can
be copied, because log records which
reside in the log system's memory buffers
are lost in the event of a system failure.
When accessing the database for critical
transactions, use DBEND mode 2 for
immediate posting of the log system's
memory buffer.
__________________________________________________
fmode can take one of the following values:
0 No records associated with failed transactions
are copied. (Default value.)
1 Log records corresponding to the first
unsuccessfully recovered call to DBBEGIN of
each transaction block are copied.
2 The sequence of log records associated with the
first unsuccessfully recovered transaction of
each transaction block are copied.
3 All log records that could not be recovered are
copied.
Discussion.
The >FILE command copies qualified DBOPEN and DBCLOSE log records to each
user's recovery file. See "File Command" in chapter 7 for a full
discussion qualifying the return of log records. The optional rmode and
fmode parameters specify the copies of additional log records.
Once the >FILE command is entered, the user recovery file is opened and
any existing records are deleted. If the specified user file does not
exist, an error is reported unless the file references the logon group
and account, in which case the file is automatically created. The state
of a log record (either recovered or not) is indicated by a flag set by
DBRECOV in the record itself. MPE/iX WRITELOG records returned by
DBRECOV are variable length, because DBRECOV eliminates the continuation
records by appending their data to the original WRITELOG record.
Consequently, DBRECOV will create recovery files with a variable length
record format. However, fixed length records are permitted if the file
already exists or an MPE/iX FILE command is in effect. If a log record
exceeds the record size of a user file with fixed length records, the log
record is truncated and an error message is printed.
Example.
>FILE PART/MGR,MARY/RYAN.MKTG,0,3
PART is the filename. MGR is the lockword. MARY is the username and
RYAN is the identifier. MKTG is the account. The 0 is the rmode, and
the 3 is the fmode.
The >FILE command is repeated for each recovery file to be created and
for each user whose records will be copied to a user recovery file.
Text Reference.
Chapter 7
>PRINT
Prints the names of databases specified for recovery (DBTABLE option) or
recovery files specified (FILETABLE option). Can be used as a check
before actually initiating recovery with the >RUN command.
NOTE The >PRINT DBTABLE command produces the DATABASE STATISTICS table,
but does not include statistics. The table, along with statistics,
is automatically displayed by every execution of the recovery
system. If you need this table, along with statistics, without
actually performing the recovery, use the >CONTROL STATS command
instead.
Syntax.
>PRINT {DBTABLE }
{FILETABLE}
Parameters.
DBTABLE displays names of databases specified for recovery
FILETABLE displays file references, user references, rmodes
and fmodes specified in >FILE commands.
Example.
>PRINT DBTABLE
****************************************************************
* DATABASE STATISTICS *
* *
* NAME GROUP ACCOUNT OPENS TRANS PUTS DELETES UPDATES *
* ---- ----- ------- ----- ----- ---- ------- ------- *
* ORDERS TST MKG 0 0 0 0 0 *
****************************************************************
Text Reference.
Chapter 7
>RECOVER
Used to designate the name of a database to be roll-forward recovered;
opens database root file, validates logid and password with MPE/iX, and
checks the DBSTORE flag. Multiple databases can be roll-forward
recovered concurrently if they have all logged to the same log file by
entering the >RECOVER command once for each database or as follows:
>RECOVER database name, database name
Syntax.
>RECOVER database name[/maint word][.group[.account]]
Parameters.
database name is the name of the TurboIMAGE/XL database to be
recovered.
maint word is the maintenance word defined by the database
creator. This word must be supplied by anyone
other than the database creator.
group is the group where the database(s) resides.
account is the account where the database(s) resides.
Discussion.
If the >RECOVER command is accepted, the following message is returned:
DATABASE database name LAST DBSTORED day, date, time
The following conditions must be satisfied before the >RECOVER command is
accepted:
1. The database must be accessible to the user (database
administrator) running DBRECOV. This user must either be the
creator of the database or know the maintenance word. If the
database resides in a group or account different from the user's
logon, the MPE/iX file security must permit the user read and
write access to the database files.
2. The database must be enabled for recovery.
3. The log identifier characteristics (name, password, log file name
and device type) must not have been altered since the log file was
generated. This restriction applies to MPE/iX log commands as
well as those provided for TurboIMAGE/XL by DBUTIL. This is
necessary because the MPE/iX log identifier is used by
TurboIMAGE/XL to obtain the name and device type of the log file.
The >RECOVER command will not be accepted if the logid is unknown
to MPE/iX. However, if the logid is known to MPE/iX but specifies
the wrong log file, this condition is not detected at this time
and >RECOVER will be accepted. DBRECOV will generate erroneous
data in the database if the database is recovered with the wrong
log file.
4. The DBSTORE flag must be set, indicating that the database has not
been modified between restoration and roll-forward recovery. This
check can be overridden by the NOSTORE option of the >CONTROL
command.
5. No other users can be accessing the database when >RECOVER is
called. Exception: When the MODE4 option of the >CONTROL command
is specified, the database can be concurrently accessed in mode 6
(read only).
The >RECOVER command itself does not initiate recovery, but makes several
preparatory checks. The recovery system is actually initiated by the
>RUN command.
Example.
>RECOVER ORDERS, RETAIL
DATABASE ORDERS LAST DBSTORED THURS, SEP 7, 1989, 6:30 PM
DATABASE RETAIL LAST DBSTORED MON, SEP 11, 1989, 10:00 PM
ORDERS and RETAIL are database names.
Text Reference.
Chapter 7
>ROLLBACK
Rolls out any incomplete transactions following a system crash. Multiple
databases can be roll-back recovered concurrently by entering the command
as follows:
>ROLLBACK dbname, dbname
Syntax.
>ROLLBACK dbname[/maint word][.group[.account]]
Parameters.
database name is the name of individual database(s) to be
rolled-back.
maint word is the maintenance word defined by the database
creator. This word must be supplied by anyone
other than the database creator.
group is the group where the database(s) resides.
account is the account where the database(s) resides.
Discussion.
If the >ROLLBACK command is accepted, the following message is returned:
DATABASE database name LAST USED day, date, time
The following conditions must be satisfied before the >ROLLBACK command
is accepted:
1. The database must be accessible to the user (database
administrator) running DBRECOV. This user must either be the
creator of the database or know the maintenance word. If the
database resides in a group or account different from the user's
on, the MPE/iX file security must permit the user read and write
access to the database files.
2. The database must have been enabled for roll-back recovery.
3. The log identifier characteristics (name, password, log file name
and device type) must not have been altered since the log file was
generated. This restriction applies to MPE/iX log commands as
well as those provided by TurboIMAGE/XL by DBUTIL. This is
necessary because the MPE/iX log identifier is used by
TurboIMAGE/XL to obtain the name and device of the log file.
4. When roll-back is enabled, DBUTIL sets a roll-back flag to
indicate that roll-back is enabled for the database. The
roll-back time stamp is updated when the database is first opened
and is logged to the log file. Roll-back recovery then uses the
time stamp during recovery to verify the correct log file for each
database.
5. No other users can be accessing the database when >ROLLBACK is
called. The database can be concurrently accessed by users when
the >CONTROL command is specified with the MODE4 option.
The >ROLLBACK command itself does not initiate recovery, but makes
several preparatory checks. The recovery system is actually initiated by
the >RUN command.
The following commands are used with >ROLLBACK:
>FILE
>PRINT
>CONTROL
The >FILE command optional parameter rmode is not used with >ROLLBACK.
The following >CONTROL options are not applicable with >ROLLBACK:
STAMP, NOSTAMP, STORE, NOSTORE, STOPTIME
Example.
>CONTROL NOSTATS
>ROLLBACK ORDERS
DATABASE ORDERS LAST USED THURS, SEP 7, 1989, 6:00 PM
>RUN
ORDERS is the database name.
Text Reference.
Chapter 7
>RUN
Initiates recovery-process. The recovery system opens the log file and
validates the log identifier before roll-forward recovery or roll-back
recovery begins.
Syntax.
>RUN
Discussion.
For recovery to succeed, the log file must be accessible to the database
administrator. This means that the database administrator must either be
the creator of the log identifier used to create the log file, or know
the maintenance word and have system manager (SM) or operator (OP)
capability. If the database administrator does not have system manager
capability, and if the log file resides on disk in a group and account
different from logon, then the administrator must have read access to the
log file according to MPE/iX file security. File equations are
permitted. However, the fully qualified file name of the expected log
file must be specified. If the log file resides on tape, the database
administrator must know the volume identifier, so that the operator can
respond to the log file tape mount request.
If recovery succeeds, tabulated information is displayed and the program
is terminated. A table of process statistics includes the number of
DBPUT, DBDELETE, and DBUPDATE log records processed and the total
transactions for each process.
When using roll-forward recovery, an asterisk (*) may appear next to any
process indicating that either a DBCLOSE record is missing or some
transactions may not have been recovered. Therefore, no asterisk for a
process in the table of process statistics indicates that all
transactions were recovered.
The same table information is displayed when using roll-back recovery;
however, there is a slight difference. The database table will list all
incomplete transactions or DBPUT, DBDELETE, and DBUPDATE log records that
were "rolled-out." An asterisk (*) will appear next to these processes.
A table of database statistics includes the same information totaled for
each database. A logging system table includes the log identifier, log
file information, and recovery file information if this facility is used.
Refer to "Recovery Tables" in chapter 7 for more information on Process,
Database, Logging and Recovery Tables.
Example 1.
Roll-forward recovery of database ORDERS.
:RUN DBRECOV.PUB.SYS
>RECOVER ORDERS
DATABASE ORDERS LAST DBSTORED FRI, SEP 22, 1989, 4:00 PM
>RUN
Example 2.
Roll-back recovery of database ORDERS.
:RUN DBRECOV.PUB.SYS
>ROLLBACK ORDERS
DATABASE ORDERS LAST USED THURS, SEP 21, 1989, 6:00 PM
>RUN
DBRESTOR
Copies a database to disk from the backup volume(s) created by the
DBSTORE program or by the MPE/iX STORE command.
Operation.
1
[:FILE DBRESTOR [=filename][;DEV=device]]
[[;REC=recsize][; {BUFNOBUF}] ]
2
:RUN DBRESTOR.PUB.SYS
:
3
WHICH DATABASE? database name [/maint word]
4
DATABASE RESTORED
END OF PROGRAM
Parameters.
filename is a name (up to 8 characters) that replaces
DBRESTOR in the mount prompt at the operator's
console.
device is the device class name of the device from which
the database is to be recorded.
recsize is the record size of the record to be restored.
recsize must be at least as large as the record
written to the device to avoid losing data.
database name is the name of a TurboIMAGE/XL database root file
to be restored.
maint word is the maintenance word defined by the database
creator. This word must be supplied by anyone
other than the database creator.
Operation Discussion.
1 An optional file equation that specifies the device class name for
the device from which the database is to be restored, the record size
of the records to be restored, and whether the records are buffered
or not. The default device class is TAPE.
2 Initiates execution of the DBRESTOR program in the PUB group of the
SYS account.
3 In session mode, DBRESTOR prompts for the database name and
maintenance word. In job mode, the database name and maintenance
word, if any, must be in the record immediately following the RUN
command.
4 After DBRESTOR has created the root file and data sets and restored
the data to these files, it prints a confirmation message.
Console Messages
After you supply the database name and DBRESTOR opens the file specified
by filename, a message is displayed on the system console. A tape must
be mounted on the appropriate unit and identified through an operator
reply. Refer to Volume Management Reference Manual for instructions
about console interaction.
If the database is on more than one volume, another message is displayed
on the system console. The operator must mount the next volume in the
sequence. If the volume that is mounted is not the correct format, the
operator is notified through a console message. If the correct volume is
available, the incorrect one should be removed and the correct one
mounted. The operator must enter a reply on the console.
Example.
:JOB MRG.ACCOUNTA Initiate job.
:RUN DBRESTOR.PUB.SYS Initiate DBRESTOR.
ORDERS/SELL Specify database name and maintenance word.
:EOJ Terminate job.
After creating the files and restoring the file contents, DBRESTOR prints
the following message on $STDLIST:
DATABASE RESTORED
NOTE If there is already a copy of the database on disc, it must be
purged using DBUTIL before running DBRESTOR.
DBSTORE
Stores the database root file and all data sets to a tape in a format
compatible with backup files created by the MPE STORE and SYSGEN
commands. DBSTORE differs from these commands in that it handles only
TurboIMAGE/XL databases.
Operation.
1
[:FILE DBSTORE[=filename] [;DEV=device][;REC=recsize] [;{BUF }]]
[ [ {NOBUF}]]
2
:RUN DBSTORE.PUB.SYS [;INFO="MPE STORE options"]
:
3
WHICH DATABASE? database name [/maint word]
4
DATABASE STORED
END OF PROGRAM
If you try to store a database that needs recovery, DBSTORE will do the
recovery before storing the database.
Before copying the files, DBSTORE gains semiexclusive access to the
referenced database; that is, DBSTORE determines that the only other
database activity consists of other users executing DBSTORE or
application programs that open the database in mode 6 or 8. If DBSTORE
cannot gain semiexclusive access, it terminates and prints the following
message:
DATABASE IN USE
You must be the database creator or provide the maintenance word to use
DBSTORE.
Parameters.
filename is the name (up to 8 characters) that replaces
DBSTORE in the mount request at the operator's
console.
device is the device class name of the device on which the
data entries are to be stored.
recsize is the record size of the record to be written to
the device; must be a multiple of 512 bytes and
less than the configured record size for the
device.
database name is the name of a TurboIMAGE/XL database to be
stored.
maint word is the maintenance word defined by the database
creator. This word must be supplied by anyone
other than the database creator.
INFO= is used for the parameters that can be passed to
the MPE STORE/RESTORE process. For example, the
TRANSPORT parameter (INFO="TRANSPORT") allows you
to migrate files from MPE/iX to MPE V with the
MPE/iX STORE command.
Operation Discussion.
1 The optional file equation that specifies the device class name for
the device on which the database is to be stored, the record size of
the records written to the device, and whether records are to be
buffered. The default device class is TAPE.
2 Initiates execution of the DBSTORE program in the PUB group of the
SYS account. The MPE STORE options are parameters that can be passed
to the STORE/RESTORE process. For example, the TRANSPORT option is
used when moving a TurboIMAGE/XL database to MPE V.
Note that the database may be too large to move to MPE V because,
with the expanded file size available on MPE/iX, data sets can exceed
the MPE V file size limit. If the database contains a data set
larger than the MPE V limit, an MPE error is displayed.
3 In session mode, DBSTORE prompts for the database name and
maintenance word. In job mode, the database name and maintenance
word, if any, must be in the record immediately following the RUN
command.
4 After DBSTORE has copied the root file and all data sets, it prints a
message to signal completion.
[REV BEG]
NOTE DBSTORE does not store jumbo data sets or B-Tree index files.
Instead, use the STORE command with POSIX names or use
TurboSTORE/iX 7x24 True-Online Backup with ONLINE=START or
ONLINE=END option.
[REV END]
Logging.
DBSTORE updates a time stamp and store flag in the database root file
before storing the database. The time stamp designates the date and time
of the DBSTORE operation, and is used by DBRECOV to help identify the
correspondence between log files and backup databases.
The store flag is set by DBSTORE to indicate that the database has been
stored; this flag is cleared (reset) when the first modification to the
database occurs by a call to DBPUT, DBUPDATE, or DBDELETE. Both DBRECOV
and DBUTIL interrogate the status of the DBSTORE flag. DBRECOV
(roll-forward) checks this flag to ensure that no one has modified the
backup database prior to recovery. DBUTIL checks this flag whenever
logging and recovery is enabled, because a valid database backup copy
must exist for roll-forward recovery to be possible. If the store flag
is not set when a DBUTIL user enables the logging option a warning is
printed:
WARNING: database modified and not DBSTORED
This warning does not necessarily indicate that a valid backup does not
exist, because either an MPE SYSGEN or STORE command could have been used
instead of DBSTORE. Because neither SYSGEN or STORE update the database
time stamp and store flag, the protection afforded by these mechanisms is
not available if this form of backup is selected. For this reason, it is
highly recommended to use DBSTORE as the backup facility when logging.
See chapter 7 for further discussion of logging and recovery.
If the mirror database maintenance method is being used, storing the
database on the secondary system can be done differently than using the
DBSTORE process. When using DBRECOV STOP-RESTART recovery on the
database, storing the database, RESTART file, and the log files that were
processed since the last successful RESTART can be done with an MPE STORE
command. DBRECOV STOP-RESTART places a time stamp in the RESTART file
and in the database to identify which RESTART file to apply to which
database. If naming conventions have been followed, an MPE STORE @
command can be used to store all the necessary files and database(s). If
DBSTORE is used, the user must remember to use an MPE STORE command to
store the RESTART file and the log files. For more information on
DBRECOV STOP-RESTART, refer to "The Mirror Database" in chapter 7.
Console Messages
After you supply the database name and DBSTORE opens the output file, a
message is displayed on the system console. A tape must be mounted on
the appropriate unit and identified through an operator reply. Refer to
the Volume Management Reference Manual for instructions about console
interaction.
If more than one volume is required to store the database, a request is
displayed on the console for the next one. The next tape must be mounted
and the unit readied. The volume that has been removed should be
properly labeled with the database name and volume number.
Example.
:JOB MGR.ACCOUNTA Initiate job.
:RUN DBSTORE.PUB.SYS Initiate DBSTORE program.
ORDERS/SELL Supply database name and maintenance word.
:EOJ Terminate job.
After copying the ORDERS root file and all data sets, DBSTORE prints the
following message on $STDLIST:
DATABASE STORED
CAUTION If you need to cancel a DBSTORE, reply zero to the tape request:
:REPLY pin#,0
Do not use Break and ABORT to abort the process when the tape
mount is requested. When DBSTORE is aborted by using Break and
ABORT, the date-time stamp and store flag in the root file are
updated even though the database was not stored.
[REV BEG]
TurboSTORE/iX 7x24 True-Online Backup
You can also use TurboSTORE/iX 7x24 True-Online Backup to back up your
database. The advantages of using the option ONLINE=START or ONLINE=END
are:
* You can store the database even when it is open for access.
* The related files including TC file, third-party indexing files,
jumbo data set files, and B-Tree index files are also stored along
with it.
* The DBSTORE flag and time stamp are also set before storing the
database.
* You can restore it using the MPE RESTORE command.
* If the database is enabled for roll-forward logging, DBRECOV can
recover the database.
* You can store multiple databases with one command.
For more information, refer to the STORE and TurboSTORE/iX Products
Manual.[REV END]