nb_db_set_max_transactions.c

int nb_db_set_max_transactions(unsigned int max)
{
#ifdef HAVE_CONFIG_ROLLBACKS
        int ret;

        /*
         * Delete old entries if necessary and update the SQL trigger that
         * auto-deletes old entries.
         */
        ret = db_execute(
                "                                                              \
                BEGIN TRANSACTION;                                             \
                 DELETE FROM TRANSACTIONS WHERE ROWID IN (SELECT ROWID FROM    \
                  TRANSACTIONS ORDER BY ROWID DESC LIMIT -1 OFFSET %u);        \
                 DROP TRIGGER delete_tail;                                     \
                 CREATE TRIGGER delete_tail AFTER INSERT ON TRANSACTIONS       \
                  FOR EACH ROW                                                 \
                  BEGIN                                                        \
                   DELETE FROM TRANSACTIONS WHERE ID%%%u=NEW.ID%%%u AND ID!=NEW.ID;\
                  END;                                                         \
                COMMIT;",
                max, max, max);
        if (ret != 0)
                return NB_ERR;
#endif /* HAVE_CONFIG_ROLLBACKS */

        return NB_OK;
}