Database Initialization Properties#
BUFFER_AREA_CHUNK_SIZE (Unit: byte)#
Data Type#
Unsigned Long
Default Value#
33554432 (32M)
AttributesValue#
Read-Only, Single Value
Range#
[8192, 264-1]
Description#
This indicates the unit, in bytes, by which the buffer size is incremented. When the buffer size is increased, it is increased in multiples of this number. This property can't be changed while the server is running.
BUFFER_AREA_SIZE (Unit: byte)#
Data Type#
Unsigned Long
Default Value#
134217728 (128M)
AttributesValue#
Read-Write, Single Value
Range#
[8 * 1024 * 10, 264-1]
Description#
This indicates the total memory size, in bytes, used by the buffer pool of Altibase. The value specified by the user will be rounded up to the nearest multiple of BUFFER_AREA_CHUNK_SIZE. The size of the buffer pool is governed by the size of the page that can be used by a single transaction and the number of transactions executing at the same time. Therefore, when modifying the property that is related to the number of pages or the DISK_INDEX_BUILD_MERGE_PAGE_COUNT property, the BUFFER_AREA_SIZE property shouldn't be too small.
BUFFER_CHECKPOINT_LIST_CNT#
Data Type#
Unsigned Integer
Default Value#
4
AttributesValue#
Read-Only, Single Value
Range#
[1, 64]
Description#
This indicates the number of checkpoint lists. The greater the number of checkpoint lists, the less lock contention there is among transactions.
BUFFER_FLUSH_LIST_CNT#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Only, Single Value
Range#
[1, 64]
Description#
This indicates the number of flush lists. The more flush lists there are, the less lock contention there is among transactions.
BUFFER_FLUSHER_CNT#
Data Type#
Unsigned Integer
Default Value#
2
AttributesValue#
Read-Only, Single Value
Range#
[1, 16]
Description#
This indicates the number of buffer flushers. This parameter can't be changed while the server is running.
BUFFER_HASH_BUCKET_DENSITY#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Only, Single Value
Range#
[1, 100]
Description#
This indicates the percentage of BCBs (Buffer Control Blocks) that can be contained in one bucket. For example, when the number of BCBs is 100, if this value is set to 1, lock contention is minimized because the number of buckets is the same as the number of buffer frames in the buffer pool. If this value is set to 2, the number of buckets is half the number of frames, whereas if this value is set to 100, there is only one bucket. As this value is increased, less memory is used; however, operational costs increase because a single bucket will manage more buffer frames.
BUFFER_HASH_CHAIN_LATCH_DENSITY#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Only, Single Value
Range#
[1, 100]
Description#
This sets the percentage of buckets that correspond to each latch in a hash table. For example, when the number of buckets is 1000, if this value is 1, one latch corresponds to ten buckets. If this value is 2, twenty buckets share a single latch. If this value is 100, only one latch exists for the entire hash table
This property is used to control concurrency when inserting a BCB (Buffer Control Block) into a hash table or deleting it therefrom. The more latches there are, the less hash chain latch contention will occur.
BUFFER_LRU_LIST_CNT#
Data Type#
Unsigned Integer
Default Value#
7
AttributesValue#
Read-Only, Single Value
Range#
[1, 64]
Description#
This indicates the number of LRU lists. LRU list lock contention among transactions decreases as this value is increased.
BUFFER_PREPARE_LIST_CNT#
Data Type#
Unsigned Integer
Default Value#
7
AttributesValue#
Read-Only, Single Value
Range#
[1, 64]
Description#
This indicates the number of prepare lists. The greater this value is, the less prepare list lock contention there is among transactions.
BULKIO_PAGE_COUNT_FOR_DIRECT_PATH_INSERT (Unit: count)#
Data Type#
Unsigned Integer
Default Value#
128
AttributesValue#
Read-Write, Single Value
Range#
[128, 12800]
Description#
This property indicates how many pages can be simultaneously written to disk when entering data using direct-path INSERT.
This property can be changed using the ALTER SYSTEM statement while Altibase is running.
COMPRESSION_RESOURCE_GC_SECOND (Unit: second)#
Data Type#
Unsigned Integer
Default Value#
3600
AttributesValue#
Read-Only, Single Value
Range#
[1, (264-1)/1000000]
Description#
This property specifies the amount of time, in seconds, that unused resources are retained in the log compression resource pool before they are discarded.
DB_NAME#
Data Type#
String
Default Value#
mydb
AttributesValue#
Read-Only, Single Value
Range#
None
Description#
This indicates the database name. When a database is created, you must set the database name to the same value as the value in this property. A new database needs to be created in order to modify the database name.
DDL_SUPPLEMENTAL_LOG_ENABLE#
Data Type#
Unsigned Integer
Default Value#
0
AttributesValue#
Read-Write, Single Value
Range#
[0, 1]
Description#
This property determines whether to add a log file when a DDL statement is executed. This property can be changed using the ALTER SYSTEM statement while Altibase is running.
0: Disabled (Do not add a log file)
1: Enabled (add a log file)
DEFAULT_DISK_DB_DIR#
Data Type#
String
Default Value#
$ALTIBASE_HOME/dbs
AttributesValue#
Read-Only, Single Value
Range#
None
Description#
This property specifies the directory in which to save the disk database files. This property must be set, even if the DRDBMS feature is not used. The default value is $ALTIBASE_HOME/dbs.
DEFAULT_MEM_DB_FILE_SIZE (Unit: byte)#
Data Type#
Unsigned Long
Default Value#
1073741824 bytes (1G)
AttributesValue#
Read-Only, Single Value
Range#
[4194304 (4M), 264-1]
Description#
This property indicates the default checkpoint image file size, in bytes, for memory tablespaces.
DEFAULT_SEGMENT_MANAGEMENT_TYPE#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Only, Single Value
Range#
None
Description#
This indicates how segments are managed when creating disk tablespaces.
0: MANUAL –segments are created on the basis of a so-called "free list" method of managing available space in the user tablespace.
1: AUTO –segments are created on the basis of a bitmap index to manage available space in the user tablespace.
DEFAULT_SEGMENT_STORAGE_INITEXTENTS (Unit: count)#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Only, Single Value
Range#
[1, 232-1]
Description#
This sets the default number of extents that are initially allocated to a segment.
DEFAULT_SEGMENT_STORAGE_MAXEXTENTS (Unit: count)#
Data Type#
Unsigned Integer
Default Value#
232-1
AttributesValue#
Read-Only, Single Value
Range#
[1, 232-1]
Description#
This sets the minimum number of extents that can be allocated to a segment.
DEFAULT_SEGMENT_STORAGE_MINEXTENTS (Unit: count)#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Only, Single Value
Range#
[1, 232-1]
Description#
This sets the minimum number of extents that can be allocated to a segment.
DEFAULT_SEGMENT_STORAGE_NEXTEXTENTS (Unit: count)#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Only, Single Value
Range#
[1, 232-1]
Description#
This sets the number of extents that can be added to an existing segment.
DIRECT_PATH_BUFFER_PAGE_COUNT (Unit: count)#
Data Type#
Unsigned Integer
Default Value#
1024
AttributesValue#
Read-Write, Single Value
Range#
[1024, 232-1]
Description#
This sets the number of pages in the direct-path INSERT buffer.
This property can be changed using the ALTER SYSTEM statement while Altibase is running.
DISK_INDEX_UNBALANCED_SPLIT_RATE (Unit: percentage)#
Data Type#
Unsigned Integer
Default Value#
90
AttributesValue#
Read-Write, Single Value
Range#
[50, 99]
Description#
In a disk B+ tree index, when the last child node of a leaf node in the lowest rank is divided, this property specifies the ratio by which to divide keys between the node to be divided and the created node. When this value is set to 90, which is the default value, the key ratio between the 2 nodes is 90:10.
This property can be changed using the ALTER SYSTEM statement while Altibase is running.
DISK_LOB_COLUMN_IN_ROW_SIZE (Unit: bytes)#
Data Type#
Unsigned Long
Default Value#
4000
AttributesValue#
Read-Only, Single Value
Range#
[0,4000]
Description#
This property sets the default column size, in bytes, when LOB type data are stored directly in disk tables. When data are entered into a LOB data type column, if the data length is smaller or the same as the value specified here, they are saved in table segment, whereas if the data are larger than this value, they are saved in a LOB segment. This property pertains only to disk tables, and has no effect on how memory tables are managed.
For more detailed information about LOB type data, please refer to Chapter1: Data Types.
DISK_MAX_DB_SIZE (Unit: byte)#
Data Type#
Unsigned Long
Default Value#
264-1
AttributesValue#
Read-Only, Single Value
Range#
64bits: [2097152, 264]
Description#
The maximum size (in bytes) Altibase allows to be set for a disk database.
When a database exceeds DISK_MAX_DB_SIZE, the transaction being executed fails as well as all subsequent SQL statements (except SELECTs)..
DOUBLE_WRITE_DIRECTORY#
Data Type#
String
Default Value#
None
AttributesValue#
Read-Only, Multiple Values
Range#
None
Description#
This specifies the directory in which double-write files are saved. Multiple values can be saved for this property, according to the value specified in DOUBLE_WRITE_DIRECTORY_COUNT.
DOUBLE_WRITE_DIRECTORY_COUNT#
Data Type#
Unsigned Integer
Default Value#
2
AttributesValue#
Read-Only, Single Value
Range#
[1, 16]
Description#
This specifies the number of directories in which double-write files are saved. Double write files can independently be saved on different disks. Because respective double-write files are used for each flusher, better flush performance can be realized when directories on different disks are specified.
DRDB_FD_MAX_COUNT_PER_DATAFILE#
Data Type#
Unsigned Integer
Default Value#
8
AttributesValue#
Read-Write, Single Value
Range#
[1, 1024]
Description#
This property specifies the maximum number of FD (File Descriptors) that can be opened for I/O operations on a single disk data file. If the maximum number of FDs specified in this property has been opened, requests to open additional FDs will wait until previous I/O operations are completed.
EXPAND_CHUNK_PAGE_COUNT#
Data Type#
Unsigned Integer
Default Value#
128
AttributesValue#
Read-Only, Single Value
Range#
[64, 232-1]
Description#
This property specifies the number of pages by which to increase the size of the memory database. An Expand Chunk is a unit that can extend a page in a memory database. The user can set it when you create the database, and if you want to change the number of pages, you need to regenerate the database.
LOB_OBJECT_BUFFER_SIZE (Unit: byte)#
Data Type#
Unsigned Integer
Default Value#
32000
AttributesValue#
Read-Only, Single Value.
Range#
[32000, 104857600]
Description#
This property specifies the maximum size of the LOB data internally used by the Altibase server in order to process LOB values during the execution of stored procedures/functions or triggers that have parameters, internal variables or return values type declared as LOB.
LOCK_MGR_CACHE_NODE#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Only, Single Value
Range#
[0, 2]
Description#
This property specifies the cache type of a table lock node. It cannot be modified during the server operation.
0: It does not cache.
1: It caches with a linked list.
2: It caches with an array, and fixed with 64
LOCK_NODE_CACHE_COUNT (Unit: count)#
Data Type#
Unsigned Integer
Default Value#
2
AttributesValue#
Read-Only, Single Value
Range#
[0, 1024]
Description#
This property specifies the number(Unit: count) of table lock nodes which will be cached if the case is LOCK_MGR_CACHE_NODE=1.
LOGANCHOR_DIR#
Data Type#
String
Default Value#
$ALTIBASE_HOME/logs
AttributesValue#
Read-Only, Multiple Values
Range#
None
Description#
This property specifies the pathnames for the log anchor files. There must be three log anchor file pathways. They are all set to the same default path.
LOG_DIR#
Data Type#
String
Default Value#
$ALTIBASE_HOME/logs
AttributesValue#
Read-Only, Multiple Values
Range#
None
Description#
This property specifies the pathname for log files
LOG_FILE_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
100 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[1024 * 1024, 264-1]
Description#
This property specifies the size, in bytes, of a log file. When an active log file fills up, writing continues in a new log file. This property can be set only when creating a database; it can't be changed afterwards. The user should create a new database in order to modify the log file size.
Restriction#
In order to perform offline replication, this property must be set the same on the local (active) server and the remote (standby) server.
MAX_CLIENT#
Data Type#
Unsigned Integer
Default Value#
1000
AttributesValue#
Read-Only, Single Value
Range#
[0, 65535]
However, if the value of JOB_THREAD_COUNT property is set to greater than 0, the maximum value is obtained by subtracting the value of the JOB_THREAD_COUNT property from 65535.
Description#
This is used to specify the maximum number of clients which can be accessed to the Altibase.
MEM_DB_DIR#
Data Type#
String
Default Value#
$ALTIBASE_HOME/dbs
AttributesValue#
Read-Only, Multiple Values
Range#
None
Description#
This property specifies the pathname for the memory database files.
It is possible to specify a minimum of 1 to a maximum of 8 paths. If multiple paths are specified, the database files are distributed among the paths. All of the paths specified using this property must be actual existing paths. The default number of paths is two, and they are both set to $ALTIBASE_HOME/dbs.
MEM_MAX_DB_SIZE (Unit: byte)#
Data Type#
Unsigned Long
Default Value#
231
AttributesValue#
Read-Only, Single Value
Range#
32-bit: [2097152, 232+1]
64-bit: [2097152, 264]
Description#
This property specifies the maximum size, in bytes, to which a memory database can dynamically increase while the server is running. The default value is 2GB for both 32-bit and 64-bit mode.
If a database expands to a size exceeding MEM_MAX_DB_SIZE, the offending transaction is treated as an error, and all subsequent SQL statements other than SELECT statements are also treated as errors.
MEMORY_INDEX_BUILD_RUN_SIZE (Unit: byte)#
Data Type#
Unsigned Integer
Default Value#
131072
AttributesValue#
Read-Write, Single Value
Range#
[1024, 232-1]
Description#
This sets the size, in bytes, of the in-memory sorting area for building memory indexes.
This property can be changed using the ALTER SYSTEM statement while Altibase is running.
MEMORY_INDEX_BUILD_VALUE_LENGTH_THRESHOLD (Unit: byte)#
Data Type#
Unsigned Long
Default Value#
64
AttributesValue#
Read-Write, Single Value
Range#
[0, 264-1]
Description#
This property sets the maximum length, in bytes, of the key value used for intermediate sorting when building memory indexes. If the length of the key value is less than this value, the key value s used for intermediate sorting. If this property is set to 0, the index build thread uses a pointer to the record rather than this key value.
This property can be changed using the ALTER SYSTEM statement while Altibase is running.
MEMORY_INDEX_UNBALANCED_SPLIT_RATE (Unit: percentage)#
Data Type#
Unsigned Integer
Default Value#
50
AttributesValue#
Read-Write, Single Value
Range#
[50, 99]
Description#
In a memory B+ tree index, when the last child node of a leaf node in the lowest rank is divided, the MEMORY_INDEX_UNBALANCED_SPLIT_RATE property sets the ratio by which to divide keys between the node to be divided and the created node.
When this value is set to 50, which is the default value, the key ratio between the 2 nodes is 50:50.
The user can change the value of the MEMORY_INDEX_UNBALANCED_SPLIT_RATE property using the ALTER SYSTEM statement while Altibase is running.
MEMORY_LOB_COLUMN_IN_ROW_SIZE (Unit: bytes)#
Data Type#
Unsigned Long
Default Value#
64
AttributesValue#
Read-Only, Single Value
Range#
[0,4000]
Description#
This property sets the default column size, in bytes, when LOB type data are stored directly in memory tables.
When data are entered into a LOB data type column, if the data length is smaller or the same as the value specified here, they are saved in a fixed amount of area, whereas if the data are larger than this value, they are saved in a variable area. This property pertains only to memory tables, and has no effect on how disk tables are managed.
For more detailed information about LOB type data, please refer to Chapter1: Data Types.
MEMORY_VARIABLE_COLUMN_IN_ROW_SIZE (Unit: bytes)#
Data Type#
Unsigned Long
Default Value#
32
AttributesValue#
Read-Write, Single Value
Range#
[0,4000]
Description#
This property sets the default column size, in bytes, when the variable type data are stored directly in memory tables. When data are entered into the variable type column, if the data length is smaller or the same as the value specified here, they are saved in a fixed amount of area, whereas if the data are larger than this value, they are saved in a variable area. This property pertains only to memory tables, and has no effect on how disk tables are managed.
For more detailed information about the IN ROW clause, please refer to Chapter1: Data Types.
MEM_SIZE_CLASS_COUNT (Unit: count)#
Data Type#
Unsigned Integer
Default#
4
AttributesValue#
Read-Only, Single Value
Range#
[1, 4]
Description#
This property determines the number of categories into which memory pages are classified based on the amount of free space in them.
MIN_COMPRESSION_RESOURCE_COUNT (Unit: counts)#
Data Type#
unsigned integer
Default Value#
16
AttributesValue#
Read-Only, Single value
Range#
[1, 16384]
Description#
This property indicates the minimum number of buffer chunks used by the log manager for log compression. (One compression buffer chunk is about 16KB.)
MIN_LOG_RECORD_SIZE_FOR_COMPRESS (Unit: bytes)#
Data Type#
Unsigned Integer
Default Value#
512
AttributesValue#
Read-Write, Single Value
Range#
[0, 232-1]
Description#
This property specifies the log size, in bytes, that is used to determine whether to compress logs. When this property is set to 0, logs are never compressed. If the size of a log exceeds the size specified here, logs will be compressed.
This property can be changed using the ALTER SYSTEM statement while Altibase is running.
MIN_PAGES_ON_DB_FREE_LIST#
Data Type#
Unsigned Integer
Default Value#
16
AttributesValue#
Read-Only, Single Value
Range#
[1, 232-1]
Description#
This property specifies the minimum number of free pages that must be available on each list of free pages. These pages are allocated to table free lists as required.
MIN_PAGES_ON_TABLE_FREE_LIST#
Data Type#
Unsigned Integer
Default#
1
AttributesValue#
Read-Write, Single Value
Range#
[ 1, 232-1]
Description#
This property specifies the minimum number of free pages that each table must maintain on its own list of free pages.
MIN_TASK_COUNT_FOR_THREAD_LIVE#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Write, Single Value
Range#
[1, 1024]
Description#
This property specifies the minimum number of clients a service thread is to be allocated in order to avoid being destroyed. If the number of clients a service thread is allocated is smaller than the value of this property, instead of being destroyed immediately, it is put in standby mode for a given time. If the number of clients allocated to the service thread on standby within the time limit set for the SERVICE_THREAD_INITIAL_LIFESPAN property is smaller than the value set for the MIN_TASK_COUNT_FOR_THREAD_LIVE property, the service thread is destroyed.
The value of this property can be changed using the ALTER SYSTEM statement while Altibase is running.
PCTFREE (Unit: Percentage)#
Data Type#
Unsigned Integer
Default Value#
10
AttributesValue#
Read-Only, Single Value
Range#
[0, 99]
Description#
This property indicates the minimum percentage of space to keep free in each page for the insertion of data. The value specified by PCTFREE indicates the percentage of space that is kept free in order to allow existing records to be updated.
If the total size of the tablespace is 100MB and the value of PCTFREE is 10, up to 90MB of data, or data equivalent in size to 90% of the total space, can be inserted.
If the value of PCTFREE is not set using a CREATE TABLE statement when a disk table is created, the default value is used.
PCTUSED#
Data Type#
Unsigned Integer
Default Value#
40
AttributesValue#
Read-Only, Single Value
Range#
[0, 99]
Description#
The PCTUSED property is the minimum percentage of used space for reinsertion when Altibase can only update record. This property indicates the amount of space that is used to convert the state of a tablespace page from one on which only updates can be performed to one on which insert operations can also be performed.
When enough data have been entered that the amount of used page space reaches the value specified in PCTFREE, only update operations can be performed. In this state, if the amount of used space falls below the value of PCTUSED due to update and delete operations, new records can be inserted.
If the value of PCTUSED is not explicitly set using a CREATE TABLE statement when a disk table is created, the default value is used.
QP_MEMORY_CHUNK_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
65536
AttributesValue#
Read-Only, Single Value
Range#
[1024, 264-1]
Description#
This property specifies the number of additional bytes allocated by the system each time the Query Processor requires additional memory.
RECYCLEBIN_DISK_MAX_SIZE (Unit: byte)#
Data Type#
Unsigned Long
Default Value#
264-1
AttributesValue#
Read-Only, Single Value
Range#
[0, 264-1]
Description#
Specifies the size of the recycle bin (in bytes) to which disk tables are moved.
The value of this property can be changed using the ALTER SYSTEM statement while Altibase is running.
RECYCLEBIN_ENABLE#
Data Type#
Unsigned Integer
Default Value#
0
AttributesValue#
Read-Write, Single Value
Range#
[0, 1]
Description#
When a table is dropped with the DROP statement, RECYCLEBIN_ENABLE specifies whether a table is to be moved to a recycle bin or dropped directly from the database system.
If the recycle bin contains a table, the table can be queried or recovered/dropped with the FLASHBACK or PURGE statement, even if the value of this property is altered to 0.
The value of this property can be changed using the ALTER SYSTEM statement while Altibase is running.
0 : Disable(default) - The table is dropped from the database.
1 : Enable - The table is moved to the recycle bin.
RECYCLEBIN_MEM_MAX_SIZE (Unit: byte)#
Data Type#
Unsigned Long
Default Value#
4 GB
AttributesValue#
Read-Write, Single Value
Range#
[0, 264-1]
Description#
Specifies the size of the recycle bin to which memory tables are dropped. The value of this property can be changed using the ALTER SYSTEM statement while Altibase is running.
REDUCE_TEMP_MEMORY_ENABLE#
Data Type#
Unsigned Integer
Default Value#
0
AttributesValue#
Read-Write, Single Value
Range#
[0, 1]
Description#
This property can minimize the space occupied by data of variable-length columns, when the data is temporarily stored in the memory tablespace.
The disk temporary tablespace is where the Altibase server temporarily stores intermediate results by default, when processing queries on disk tables or views. To enhance performance, intermediate results can be stored in the memory tablespace, using the TEMP_TBS_MEMORY hint(please refer to Administrator's Manual and Performance Tuning Guide).
The default value 0 can occupy unnecessary space, due to data of variable-length columns using temporary storage space of a fixed length, as data of fixed-length columns do. To reduce such waste of space, this property can be set to 1 and only as much space as the actual data of the variable-length column is used. While memory usage is smaller, however, the speed of query processing can slow down.
0: The variable-length columns use as much temporary storage space as the length defined.
1: The variable-length columns use as much temporary storage space as the actual data.
The value of this property can be changed using the ALTER SYSTEM statement while Altibase is running.
SECURITY_ECC_POLICY_NAME#
Data Type#
String
Default Value#
None
AttributesValue#
Read-Write, Single Value
Range#
None
Description#
This property indicates the name of the ECC (Encrypted Comparison Code) algorithm used when you run the security module for the encrypted columns.
SECURITY_MODULE_LIBRARY#
Data Type#
String
Default Value#
None
AttributesValue#
Read-Write, Single Value
Range#
None
Description#
This property indicates the library file name of the security module, and is used when you perform the security module.
SECURITY_MODULE_NAME#
Data Type#
String
Default Value#
None
AttributesValue#
Read-Write, Single Value
Range#
None
Description#
This property indicates the name of the security module, and is used when you perform the security module.
SERVICE_THREAD_INITIAL_LIFESPAN#
Data Type#
Unsigned Integer
Default Value#
6000
AttributesValue#
Read-Write, Single Value
Range#
[30, 232-1]
Description#
This property specifies the number of times necessary for the thread manager to check the status of standby service threads, in order to destroy the threads. If the standby service threads are not allocated a client for the number of times the thread manager has set for this property, they are destroyed.
Service threads are placed on standby when they are allocated a smaller number of clients than the value set for the MIN_TASK_COUNT_FOR_THREAD_LIVE property.
The value of this property can be changed using the ALTER SYSTEM statement while Altibase is running.
SMALL_TABLE_THRESHOLD#
Data Type#
Unsigned Integer
Default Value#
128
AttributesValue#
Read-Write, Single Value
Range#
[0, 232-1]
Description#
When a full scan is performed on a disk table, if the number of pages in the table is equal to or less than the number specified in this property, the pages that have been read from disk to a buffer all at one time will remain in the buffer after the full scan. If the number of pages in the table is greater than the number specified here, the pages will not remain in the buffer.
If this property is set to 0, no pages will be maintained in buffers regardless of the number of pages in the table.
If this property is set to the maximum value, which is 232-1, pages will always remain in buffers, regardless of the number of pages in a table.
ST_OBJECT_BUFFER_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
32000 (32KByte)
Properties#
Read-Write, Single Value
Range#
[32000, 104857600]
Description#
This sets the maximum size, in bytes, of a single geometry object.
SYS_DATA_FILE_INIT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default#
100M (100 * 1024 * 1024)
AttributesValue#
Read-Only, Single Value
Range#
[8*8KB, 32GB]
Description#
This specifies the initial size, in bytes, of the data file (system001.dbf) when SYS_TBS_DISK_DATA (system disk tablespace) is created. Moreover, if the initial size is not specified when a data file (that is, a user-specified file other than system001.dbf) is added to SYS_TBS_DISK_DATA, the initial size of that data file also defaults to the value specified here.
SYS_DATA_FILE_MAX_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
2 * 1024 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[8 * 8KB, 32GB]
Description#
This property specifies the maximum size, in bytes, of the allocated data file when SYS_TBS_DISK_DATA (system disk tablespace) is created. It must be equal to or greater than the value of SYS_DATA_FILE_INIT_SIZE. The minimum possible value is 64KB.
Moreover, if no maximum value is set when data files are added to SYS_TBS_DISK_DATA (system disk tablespace), the value specified here will be taken for SYS_DATA_FILE_MAX_SIZE.
SYS_DATA_FILE_NEXT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
1 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[8 * 8KB, 32GB]
Description#
When the autoextend property of the system disk tablespace (SYS_TBS_DISK_DATA) is set to "autoextend on", data files are automatically incremented in size by the number of bytes specified here in order to accommodate increased amounts of data.
If the size of a data file reaches the value specified in SYS_DATA_FILE_MAX_SIZE , and additionally the amount of valid space in other data files is less than that specified in SYS_DATA_FILE_NEXT_SIZE, an insufficient tablespace error will be raised.
SYS_DATA_TBS_EXTENT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
512 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[40K, 32G]
Description#
This specifies the size, in bytes, of an extent when SYS_TBS_DISK_DATA (system disk tablespace1) is created . In order for an extent to contain at least 5 pages, the minimum value of this property is 40KB (5*8KB)2.
SYS_TEMP_FILE_INIT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
100M (100 * 1024 * 1024)
AttributesValue#
Read-Only, Single Value
Range#
[ 8 * 8KB, 32GB]
Description#
This specifies the initial size, in bytes, of the temporary data file (temp001.dbf) when SYS_TBS_DISK_TEMP is created. Moreover, if the initial size is not specified when a temporary data file is added to SYS_TBS_DISK_TEMP, the value specified here is used.
SYS_TEMP_FILE_MAX_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
2 * 1024 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[8 * 8KB, 32GB]
Description#
This specifies the maximum size, in bytes, of the data file (temp001.dbf) that is allocated when SYS_TBS_DISK_TEMP is created.
The value of this property must be at least as great as that of SYS_TEMP_FILE_INIT_SIZE. The minimum possible value is 64KB. Moreover, if the maximum size is not specified when a temporary data file is added to SYS_TBS_DISK_TEMP, the size specified here is the default maximum size.
SYS_TEMP_FILE_NEXT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
1 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[8 * 8KB, 32GB]
Description#
If there is not enough space in a data file in the SYS_TBS_DISK_TEMP tablespace, the size of the file is increased by the amount specified here.
SYS_TEMP_TBS_EXTENT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
256 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[40KB, 32GB]
Description#
This specifies the size, in bytes, of an extent when the SYS_TBS_DISK_TEMP (system disk temporary tablespace)3 is created.
It must be large enough to contain at least five pages (40KB = 5 * 8KB).
SYS_UNDO_FILE_INIT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
100 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[32 * 8KB, 32GB]
Description#
This specifies the default size, in bytes, of the data file (undo001.dbf) when the SYS_TBS_DISK_UNDO tablespace is created. Additionally, when a data file is added to SYS_TBS_DISK_UNDO without specifying its initial size, the size specified here is used.
SYS_UNDO_FILE_MAX_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
2 * 1024 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[32 * 8KB, 32GB]
Description#
This specifies the maximum size, in bytes, of the data file (undo001.dbf) that is allocated when the SYS_TBS_DISK_UNDO is created.
The value of this property must be at least as great as that of SYS_UNDO_FILE_INIT_SIZE. The minimum possible value is 256KB. Moreover, if the maximum size is not specified when a temporary data file is added to SYS_TBS_DISK_UNDO, the value specified here is used as the default maximum size.
SYS_UNDO_FILE_NEXT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
1 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[8 * 8KB, 32GB]
Description#
When there is not enough space in the SYS_TBS_DISK_UNDO tablespace data file, the size of the data file is incremented by the number of bytes specified here.
SYS_UNDO_TBS_EXTENT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
256 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[40KB, 32GB]
Description#
This specifies the size, in bytes, of an extent when SYS_TBS_DISK_UNDO (system disk undo) 4 is created.
TABLE_BACKUP_FILE_BUFFER_SIZE (Unit: byte)#
Data Type#
Unsigned Integer
Default Value#
1024
AttributesValue#
Read-Only, Single Value
Range#
[0, 1048576]
Description#
This property specifies the table backup buffer size, in bytes, for use when using the ALTER TABLE command to add or delete columns to or from memory tables.
TABLE_COMPACT_AT_SHUTDOWN#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Write, Single Value
Range#
[0, 1]
Description#
This property indicates whether to compact tables when you shut down the database. It is recommended to specify this property as 1 to reduce memory consumption of tables when you restart the database.
TEMP_HASH_BUCKET_DENSITY#
Data Type#
Unsigned Integer
Default Value#
1
AttributesValue#
Read-Only, Single Value
Range#
[1, 50]
Description#
This specifies as a percentage the number of page frames of a temporary table one hash bucket is to manage. As this value increases, less memory is used as the number of necessary hash buckets decreases; however, operational costs increase since the number of temporary page frames to be managed per bucket increases.
For example, when the number of temporary page frames is 100 and this value is set to 1, the number of buckets and frames are the same. If this value is set to 2, the number of buckets is 50, half the number of frames, whereas if this value is set to 100, there is only one bucket.
TEMP_PAGE_CHUNK_COUNT#
Data Type#
Unsigned Integer
Default Value#
128
AttributesValue#
Read-Only, Single Value
Range#
[1, 232-1]
Description#
This property indicates the number of temporary data pages that can be allocated at one time.
USER_DATA_FILE_INIT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
100 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[8 * 8KB, 32GB]
Description#
This property sets the initial size, in bytes, of a user-defined data file that is created or added to a user disk data tablespace. The default value specified here is used if no initial size is specified.
USER_DATA_FILE_MAX_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
2 * 1024 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[8 * 8KB, 32GB]
Description#
This sets the maximum size, in bytes, of a user-defined data file that is created or added to a user disk data tablespace.
The value of this property should be at least as big as that specified in USER_DATA_FILE_INIT_SIZE. The minimum possible value is 64KB. If no maximum size is specified when a data file is created or added, the default value specified here is used.
USER_DATA_FILE_NEXT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
1 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[8 * 8KB, 32GB]
Description#
If the data file in the user-defined data file of the user disk data tablespace lacks space, the data file size is increased as specified for this property.
USER_DATA_TBS_EXTENT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
512 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[2 * 8KB, 264-1]
Description#
This specifies the size, in bytes, of an extent when a user disk data tablespace5 is created.
USER_TEMP_FILE_INIT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
100 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[8 * 8KB, 32GB]
Description#
This specifies the initial size, in bytes, of a data file when a user-defined temporary data file is created or added to a user temporary tablespace. If no initial size is specified, the default value specified here is used.
USER_TEMP_FILE_MAX_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
2 * 1024 * 1024 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[8 * 8KB, 32GB]
Description#
This property limits the maximum size, in bytes, of user-defined temporary data files that are created in or added to a user temporary tablespace.
This parameter must be at least as great as USER_DATA_FILE_INIT_SIZE. The minimum possible value is 64KB. If no maximum size is specified when temporary data files are created or added, the default value specified here is used.
USER_TEMP_FILE_NEXT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
1 * 1024 * 1024
AttributesValue#
Read-Only, Single value
Range#
[8 * 8KB, 32GB]
Description#
If there is insufficient space in a user-defined temporary data file in a user temporary tablespace, the size of the data file is increased by the number of bytes specified here.
USER_TEMP_TBS_EXTENT_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
256 * 1024
AttributesValue#
Read-Only, Single Value
Range#
[2 * 8KB, 264-1]
Description#
This specifies the size, in bytes, of an extent when a user temporary tablespace is created. It must be at least 2 pages (16KB = 2 * 8KB).
VOLATILE_MAX_DB_SIZE (Unit: byte)#
Data Type#
Unsigned long
Default Value#
232+1
AttributesValue#
Read-Only, Single Value
Range#
32 bits: [2097152, 232+1]
64 bits: [2097152, 264]
Description#
This property specifies the maximum size, in bytes, of volatile tablespaces.
-
System Disk Data Tablespace: This is the disk tablespace that is created by default when a database is created. The disk table and disk index are the only database objects that are saved. ↩
-
The initial extent size cannot be changed after the database has been created. The default value is 32 pages. ↩
-
System disk temporary tablespace: This is automatically created by default when a database is created, and is a tablespace for temporary storage related to various kinds of database operations. It is set as the default temporary tablespace for storing objects on disk for all users. The only database objects that are stored here are disk tables and disk indexes. ↩
-
System disk undo tablespace: This is automatically created by default when a database is created, and is used only for saving undo information. Only one system disk undo tablespace exists in a database. The user cannot create or delete tables, indexes, or anything else in the system disk undo tablespace. ↩
-
User disk data tablespace: This is a tablespace for storing user objects. Only disk tables and disk indexes are stored among database objects. ↩