Initialize Microsoft Jet 4.0 Database Engine Driver
When you install the Microsoft® Jet 4.0 engine database driver, the installer writes a group of defaults to the Microsoft Windows® registry and the ISAM format subkey in the engine. You must use the Registry Editor to add, delete, or change these settings. The following sections describe the initialization of the Microsoft Jet Engine Database Driver and ISAM Format Settings. The Microsoft Jet Engine Initialization Settings Jet / 4.0 / Engines folder includes an initial setting of the MSJET40.DLL database engine (accessing the Microsoft Access database). The following example shows the typical initialization settings of each item in this folder. Systemdb =
Item Description SystemDB Specifies the full path and file name of the workgroup information file. The default value is the corresponding path with the filename system.mdb behind the file. CompactBypkey specifies that when there is a primary key in your compression table, these tables are copied in the primary key; if there is no primary key in the table, these tables are replicated in the base form. Value 0 indicates that the table should be compressed in the base form; the non-zero value indicator should be compressed in primary key (if a primary key exists). The default is a non-zero value. Note This setting is only available to compress the database created using the Microsoft Jet Database Engine 3.0 or higher. When you compress the database created using the Microsoft Jet Database Engine 2.x, you always copy data in the base form. PrevformatCompactWithunicateOndeCompressionMicrosoft Jet 4.0 Database Use the Unicode character set to store text data. Compress Unicode data can reduce the number of page read / write operations required in the future, so it can significantly improve the performance of the database. This button determines that the database created using the Microsoft Jet Database Engine 3.x or earlier is created by the compressed Unicode or should be created by uncompressed Unicode. Note This setting does not apply to compressing the Microsoft Jet 4.0 database. In the default mode, the Microsoft Jet 4.0 database will keep the compression settings used when creating them. The initial setting of the MSJET40.DLL database engine (to access the Microsoft Access database) is included in the Jet / 4.0 / Engines / Jet 4.0 folder. The following example shows the typical initialization settings of each item in this folder. FlushTransactionTimeout = 500 LockDelay = 100 LockRetry = 20 MaxBufferSize = 0 MaxLocksPerFile = 9500 PageTimeout = 5000 Threads = 3 UserCommitSync = Yes ImplicitCommitSync = No ExclusiveAsyncDelay = 2000 SharedAsyncDelay = 0 RecycleLVs = 0 PagesLockedToTableLock = 0 Microsoft Jet database engine uses the following items.
Item Description PageTimeout The length of time length between the data failed to place the unlocked data in the internal cache, is represented in milliseconds. The default is 5000 milliseconds (i.e., 5 seconds). FlushTransactionTimeout This item disables the ExclusiveasyncDelay and SharedAsyncDelay registry. To enable these items, you must enter a value of 0. FlushTransActionTimeout can change the Microsoft Jet database engine for asynchronous writing to the database file. Previously, the Microsoft Jet database engine used ExclusiveasyncDelay or SharedAsyncDelay to determine how long it was waiting before forced asynchronous writing. FlushTransActionTimeout can change this behavior, the method is set a value such that only asynchronous writing is activated only when the specified number of times is not expired. Only one case exception, that is, if the cache exceeds MaxBuffersize. The cache will start asynchronous writing when MaxBuffersize is reached, regardless of whether the time expires. The Microsoft Jet 3.5 database engine will wait for non-active time to reach 500 milliseconds or wait until the cache size will begin asynchronous writing. Lockdelay This setting works with the Lockretry setting because it causes each LockRetry to wait for 100 milliseconds to issue another lock request. Adding a LockDelay setting is to prevent "outbreak" in some network operating systems. MaxLockSperfile This setting prevents transaction processing from Microsoft Jets to exceed the specified value. If the locked number in the transaction is trying to exceed this value, the transaction will be split into two or more portions, submitted one by one. Add this setting to prevent the NetWare 3.1 server crash when you exceed the specified NetWare lock limit and improve NetWare and NT performance. LockRet Repeats the number of times to access the lock page before returning to lock conflict messages. The default is 20. RecyClelvs This setting will make the Microsoft Jet loop long numeric type (LV) page (note, long binary [ole object] and binary data type). Before the last user turns off the database, Microsoft Jet 3.0 does not loop these types of pages. If RecyLELVS settings are enabled, Microsoft Jet 3.5 starts loop most of the LV page when the database is extended (ie, when adding a page group). Note When this feature is enabled, the user can notice that performance will decrease during processing long value data types. Microsoft Access 97 will automatically enable and disable this feature when processing modules, forms, and reports, so it is not necessary to enable it when modifying these objects. The default is 0. The size of the MaxBuffersize database engine has a size in KB. The MaxBuffersize must be an integer value greater than or equal to 512. The default value is based on the following formula: ((Total Memory (MB) - 12 MB) / 4) 512 KB, for example, the default buffer size is ((32 MB - 12 MB) / 4) 512 KB (ie 5632 KB). To set this value as a default, you will be requested to be maximsize = threads for the backend thread of the Microsoft Jet database engine. The default is 3. UserCommitSync Specifies whether the system waits for submission. The value "Yes" indicates the system waiting; the value "No" indicates that the system is submitted for submission. The default is "Yes". ImplicitCommitSync Specifies whether the system waits for submission.
The value "No" indicates that the system continues, not to wait for the submission; the value "Yes" indicates that the system is waiting to be submitted; the default is "No". ExclusiveasyncDelay specifies the length of time (in milliseconds) that delay asynchronous refresh exclusive database. The default is 2000 (ie 2 seconds). SharedAsyncDelay specifies the length of time (in milliseconds) that delay the asynchronous refresh shared database. The default is 0. PageSlockedTotableLock During the batch operation, the entire table is locked (instead of locking this page when trying to access the table) is usually more effective. This setting specifies that the Microsoft JET allows the number of pages that are locked in any particular transaction in any particular transaction, indicating that the Jet is changed to the table lock in any particular transaction. Note This setting should be cautious. If multiple users need to access the database, locking the entire table may cause lock conflicts to other users. This problem is particularly severe if the number is used in this setting. Even with large numbers (e.g., 25 or 50), other users can become unpredictable. The Microsoft Jet Engine Copy Settings Jet / 4.0 / Transporter key includes initialization settings used when JET replication synchronization via the Jet Synchronizer. These settings determine that the synchronizer will try to use the specific transmission order. Valid value is 0-100. Value 0 means that transmission should not be tried. All transfer types of non-zero values will be tried in the ascending order of the key value until synchronization is successfully executed or until all attempts fail. The following example shows the typical initialization settings of each item in this folder. Priority_fs = 1 priority_internet = 2 priority_direct = 3 Microsoft Jet Database Engine uses the following priority items. Item Description Priority_fs file system (indirect) Synchronization depends on a series of messages between copies. Managing the synchronizer of each copy will be changed in the message file (* .msg), which will then copy it into a shared folder called a drop-down box, which can be used by the partner synchronizer and can be made through the file system access. Priority_InterNetInternet (indirect) Synchronization Depending on a series of messages between copies. Only copies managed by the synchronizer managed by the Internet server have a drop-down box that can be accessed via HTTP or FTP. Priority_direct Direct Synchronization is a process of switching data changes and design changes between two replica sets (on the same computer or through network). The synchronizer can open both databases at the same time. Note When you change the Windows Registry Setup, you must quit the database engine before restarting it, so that new settings take effect. See Windows Registry Settings for Custom Microsoft Jet
