ttDBWriteConcurrencyModeSet
The ttDBWriteConcurrencyModeSet
built-in enables control over read optimization during periods of concurrent write operations.
Set the mode to one (1) to enable the enhanced write concurrency mode and disable read optimization. Set the mode to zero (0) to disable the enhanced write concurrency mode and re-enable read optimization.When the mode is set to one (1
), all transaction and statement table lock hints are suppressed. This affects hint-triggered Sn
table locks for SELECT
statements and subqueries and also hint-triggered W
table locks for DML statements. Suppression of the table lock hint also suppresses other table-lock hint driven execution plans such as star joins. Regardless of the mode setting, table locks that are not triggered by table-lock hints are not affected.
Required Privilege
This procedure requires ADMIN
privilege.
Usage in TimesTen Scaleout and TimesTen Classic
This procedure is supported in TimesTen Classic.
TimesTen Scaleout applications can call this built-in procedure.
In TimesTen Scaleout, this procedure runs on all elements in the grid.
Related Views
This procedure has no related views.
Syntax
ttDBWriteConcurrencyModeSet(mode, wait)
Parameters
ttDBWriteConcurrencyModeSet
has these parameters:
Parameter | Type | Description |
---|---|---|
|
|
The write concurrency mode:
|
|
|
|
Result Set
ttDBWriteConcurrencyModeSet
returns no result set:
Examples
The following example shows how to enable standard optimization techniques and return immediately after starting the operation:
CALL ttDBWriteConcurrencyModeSet(0,0);
Note:
When the mode is set to one (1), all transaction and statement table lock hints are suppressed. This affects hint-triggered Sn
table locks for SELECT
statements and subqueries and also hint-triggered W
table locks for DML statements. Suppression of the table lock hint also suppresses other table-lock hint driven execution plans such as star joins. Regardless of the mode setting, table locks that are not triggered by table-lock hints are not affected.
See Also