The following parameters are database parameters that specify special database properties:
_EVENT_ALIVE_CYCLE |
The time in seconds of an event cycle |
_MAX_MESSAGE_FILES |
Maximum number of trace files that can be open simultaneously |
_MAXEVENTS |
Maximum number of events stored by the kernel in the cache for processing by the Database Manager |
_UNICODE |
see _UNICODE |
CAT_CACHE_SUPPLY |
Size of catalog cache memory for all user tasks in pages |
DATE_TIME_FORMAT |
System default for the date and time format |
DEADLOCK_DETECTION |
Maximum search level for deadlock detection. Deadlocks that have not been detected by the deadlock detection up to the given search level of the specified value are only resolved by the parameter REQUEST_TIMEOUT. If DEADLOCK_DETECTION = 0, deadlock detection is disabled. |
DEFAULT_CODE |
See DEFAULT_CODE |
DEVNO_BIT_COUNT |
See DEVNO_BIT_COUNT |
DIAG_HISTORY_NUM |
Number of histories in the <diag_history_path> directory |
DIAG_HISTORY_PATH |
Directory <diag_history_path> for the histories of log files The default value is DIAGHISTORY in the run directory of the database instance. |
JOIN_MAXTAB_LEVEL4 |
Threshold value for the number of tables in a join for selecting the join sequence algorithm. The default value is 16. |
JOIN_MAXTAB_LEVEL9 |
Threshold value for the number of tables in a join for selecting the join sequence algorithm. The default value is 4. |
JOIN_SEARCH_LEVEL |
|
KERNELDIAGSIZE |
Size of the log file knldiag in KB |
LOG_BACKUP_TO_PIPE |
Specifies whether log backup in pipes is permitted |
LOG_IO_QUEUE |
Size of the log queue in pages |
LRU_FOR_SCAN |
Specifies whether the entire data cache is used for scans |
MAXRGN_REQUEST |
Maximum number of attempts a task should make to access a critical region. If this number is exceeded, the task lets another task access the CPU as long as it belongs to the same user kernel thread. |
MAXSERVERTASKS |
Determines the number of server tasks that are, for example, available for backup and restore |
MP_RGN_LOOP |
Maximum number of times a task may attempt to access a critical section that has been locked by another task. If this number is exceeded, the accessing task changes its status “Waiting”. |
OPTIM_INV_ONLY |
Determines whether the Index Only strategy is used for joins |
OPTIM_MAX_MERGE |
Specifies the change of the optimizer algorithm’s strategies for merging index lists If the number of pages of an index that need to be merged exceeds the value specified in OPTIM_MAX_MERGE, this index will not be used for an index merging strategy. |
REQUEST_TIMEOUT |
|
SEQUENCE_CACHE |
The size of the sequence cache in pages |
SESSION_TIMEOUT |
see SESSION_TIMEOUT |
UTILITY_PROT_SIZE |
Size of the log file dbm.utl in pages |
You can display the full list of special database parameters for your database instance and additional information about these parameters using the Database Manager.