mco_trans_checkpoint

RT

Checkpoint a transaction.

Prototype

    MCO_RET	mco_trans_checkpoint(	/*IN*/ mco_trans_h t );

Arguments

Description

This function inserts updated objects into indexes. It behaves differently depending on the transaction manager in use. With the pessimistic transaction manager, MURSIW, updated objects are removed from the indexes and it is not possible to locate them using the old key until the checkpoint (or commit) is called. With the optimistic transaction manager, MVCC, the working copy of the object is created, but the old version is not removed and it is possible to access this copy using the original value of the key (or iterating through the index). After the checkpoint, only the new key can be used to locate the object.

Return Codes

Example

    Application snippet:

    const char * dbname = "SimpleDb";

    int main(int argc, char* argv[])
    {
        mco_db_h db;
        MCO_RET rc;
        mco_device_t       dev;
        mco_db_params_t    db_params;
        mco_trans_h t;

        ...
        rc = mco_db_open_dev( dbname, simple_get_dictionary(), &dev, 1, &db_params );
        if ( MCO_S_OK != rc )
        {
            rc = mco_db_connect(  dbname, &db );
            ...
            rc = mco_trans_start(db, MCO_READ_ONLY, MCO_TRANS_FOREGROUND, &t);
            if ( MCO_S_OK == rc )
            {
                ...
                rc = mco_trans_checkpoint( t );

                ...
                rc = mco_trans_commit( t );
                ...
            }
        }
        ...
    }

Files