PurgeTransactionSequenceData Method
Purges the specified data from the transaction history table.
Namespace: System.Data.SqlServerCe
Assembly: System.Data.SqlServerCe (in System.Data.SqlServerCe.dll)
Syntax
'Declaration
Public Sub PurgeTransactionSequenceData ( _
pType As PurgeType, _
retentionValue As Long _
)
'Usage
Dim instance As SqlCeChangeTracking
Dim pType As PurgeType
Dim retentionValue As Long
instance.PurgeTransactionSequenceData(pType, _
retentionValue)
public void PurgeTransactionSequenceData(
PurgeType pType,
long retentionValue
)
public:
void PurgeTransactionSequenceData(
PurgeType pType,
long long retentionValue
)
member PurgeTransactionSequenceData :
pType:PurgeType *
retentionValue:int64 -> unit
public function PurgeTransactionSequenceData(
pType : PurgeType,
retentionValue : long
)
Parameters
- pType
Type: System.Data.SqlServerCe. . :: . .PurgeType
One of the values of PurgeType that specifies whether the purge is time based or based on the commit sequence number (CSN) of the last transaction to modify the transaction history data.
- retentionValue
Type: System. . :: . .Int64
A number that specifies the limit up to which rows should be retained. In the case of a time based purge the parameter specifies the number of days from the present date for which to retain transaction history data. In the case of a CSN based purge, the parameter specifies the CSN of the last transaction for which transaction history data should be retained.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentOutOfRangeException | retentionValue is less than zero. -or- purgeType is not a valid PurgeType value. |
Remarks
As transactions commit, an entry is made into the transaction history table (__sysTxCommitSequence) that contains tracking information relevant to the transaction. You can limit the size of this table by deleting rows for transactions that are no longer relevant to your application.
You can specify one of two types of purge by using the pType parameter:
A time based purge. In the case of a time based purge, the retentionValue parameter specifies the number of days from the current date for which rows are retained in the transaction history table. Any row that was modified on or after the retention date is retained; any row that was modified before the retention date is deleted.
A CSN based purge. This type of purge is also known as a transaction based purge. In the case of a CSN based purge, the retentionValue parameter specifies the transaction commit sequence number (CSN) of the last transaction for which to retain rows in the transaction history table. Rows that were last modified by a transaction with a CSN that is greater than or equal to the specified CSN are retained; those that were last modified by a transaction with a CSN less than the specified CSN are deleted. You can get the current CSN for a data source (the CSN assigned to the last transaction to commit) by calling the GetLastCommittedCsn method.
Note
The CSN is a monotonically incrementing counter that is assigned by the database to each transaction (in which the database is enlisted) when it commits. The CSN uniquely identifies the sequence in which each transaction was committed relative to other transactions that that have committed in which the database was also enlisted.
For more information about the differences between performing a time based purge and a CSN based purge, see the topic for the PurgeType enumeration.