MSGID nextMessageId() {
return NextMsgId.fetchAndAdd(1);
}
/**
* Generates a new file name on each call using a static, atomic and monotonically increasing
* number.
*
* Each user of the Sorter must implement this function to ensure that all temporary files that the
* Sorter instances produce are uniquely identified using a unique file name extension with separate
* atomic variable. This is necessary because the sorter.cpp code is separately included in multiple
* places, rather than compiled in one place and linked, and so cannot provide a globally unique ID.
*/
std::string nextFileName() {
static AtomicWord<unsigned> indexAccessMethodFileCounter;
return "extsort-index." + std::to_string(indexAccessMethodFileCounter.fetchAndAdd(1));
}