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CheckPointTXN

CheckPointTXN

CheckPointTXN

Attention: This command is deprecated and will no longer be supported in future ClassiX versions, as the performance advantage of CheckPointTXN is marginal.

Stack
Stack Position Description
Stack(In) Top -
Stack(Out) Top -

The call of this command corresponds to the sequence EndTXN, BeginTXN, i.e. the current transaction is ended and another transaction is started immediately afterwards.
With CheckPointTXN, all read locks on the pages are preserved and all write locks are converted to read locks. If a longer processing step is to be split into several transactions, CheckPointTXN is more effective than EndTXN and (explicitly or automatically by InstantView®) BeginTXN following it.

An AbortTxn does not undo the changes that occurred BEFORE the CheckPointTXN!

If a read-only transaction is currently running (BeginTXN(READ)), CheckPointTXN behaves in the same way, except that due to the read-only mode there are no changes that could be written to the database. The only interesting thing about CheckPointTXN in connection with read-only transactions is the update of the image of the database. Because within a read-only transaction a so-called snapshot of the database is used (MVCC mode), which does not reflect changes in the data since the beginning of the transaction, it can be useful to update this snapshot with CheckPointTXN.

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