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 |
Parameter for creating a UNICODE-compliant database You can no longer change this database parameter after you have created the database instance. |
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. Any deadlocks that are not detected at this search level are only resolved by the parameter REQUEST_TIMEOUT. If DEADLOCK_DETECTION = 0, deadlock detection is disabled. |
DEFAULT_CODE |
Determines the default code attribute of the database instance. This default is then used for saving the column values of the data types CHAR[ACTER], VARCHAR, and LONG[VARCHAR]. |
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. |
JOIN_MAXTAB_LEVEL9 |
Threshold value for the number of tables in a join for selecting the join sequence algorithm. |
JOIN_SEARCH_LEVEL |
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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 section. 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 available, for example, for backups and restores |
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 of the 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 |
Maximum wait before a lock is released (in seconds) This database parameter limits the amount of time you have to wait until a lock is released by other users for all database sessions. If a lock request cannot be satisfied within the time defined here, a message is returned to the waiting database session. Any changes made previously in the transactions are undone. |
SEQUENCE_CACHE |
The size of the sequence cache in pages |
SESSION_TIMEOUT |
Timeout value for database sessions in seconds |
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.