While most MUPIP operations can be performed when GT.M processes are actively accessing database files, some operations require stand-alone access. When using standalone access, no other process can access the database file(s). When using concurrent access, other processes can read or update the database file(s) while MUPIP accesses them. A few operations permit concurrent access to read database files, but not to update them. All MUPIP operations can be performed with stand-alone access - there is never a requirement for another process to be accessing database files when MUPIP operates on them.
Most MUPIP operations require write access to the database files with which they interact. The exceptions are INTRPT and STOP, which do not require database access, but may require other privileges; EXTRACT, which requires read access; and INTEG, which may require write access, depending on the circumstances it encounters and the qualifiers with which it is invoked. The following table displays some of the MUPIP operations and their database access requirements.
|
Operations |
MUPIP command |
Database Access Requirements |
|---|---|---|
|
Backup database files |
MUPIP BACKUP |
Backup never requires standalone access and concurrent write access is controlled by -[NO]ONLINE. |
|
Create and initialize database files |
MUPIP CREATE |
Standalone access |
|
Converts a database file from one endian format to the other (BIG to LITTLE or LITTLE to BIG) |
MUPIP ENDIANCVT |
Standalone access |
|
Recover database files (for example, after a system crash) and extract journal records |
MUPIP JOURNAL |
Standalone access |
|
Restore databases from bytestream backup files |
MUPIP RESTORE |
Standalone access |
|
Properly close database files when processes terminate abnormally. |
MUPIP RUNDOWN |
Standalone access |
|
Modify database and/or journal file characteristics |
MUPIP SET |
Standalone access is required if the MUPIP SET command specifies -ACCESS_METHOD, -GLOBAL_BUFFERS, LOCK_SPACE or -NOJOURNAL, or if any of the -JOURNAL options ENABLE, DISABLE, or BUFFER_SIZE are specified. |
|
Backup database files |
MUPIP BACKUP |
Concurrent access. |
|
Grow the size of BG database files |
MUPIP EXTEND |
Concurrent access. |
|
Export data from database files into sequential (flat) or binary files |
MUPIP EXTRACT |
Although MUPIP EXTRACT command works with concurrent access, it implicitly freezes the database to prevent updates. Therefore, from an application standpoint, you might plan for a standalone access during a MUPIP EXTRACT operation. |
|
Prevent updates to database files |
MUPIP FREEZE |
Standalone access. |
|
Check the integrity of GDS databases |
MUPIP INTEG |
Concurrent access. However, standalone access is required if MUPIP INTEG specifies -FILE. |
|
Import data into databases |
MUPIP LOAD |
Although MUPIP LOAD works with concurrent access, you should always assess the significance of performing a MUPIP LOAD operation when an application is running because it may result in an inconsistent application state for the database. |
|
Defragment database files to improve performance |
MUPIP REORG |
Concurrent access. |
|
Send an asynchronous signal to a GT.M process |
MUPIP INTRPT |
Non-database access. |
|
Stop GT.M processes |
MUPIP STOP |
Non-database access. |