Will resolver's keys be garbage collected?

Development FoundationDB Core
1

Say we have a range map that maps [a, f) to resolver#1, and we insert (a, 1) , (b, 1), (c, 1) into resolver#1, and then it triggers master to start a resolution split process as in link. Suppose, resolver#1’s new range is [a, c), but will key c got garbage collected in the skip list? I didnt find any code in SkipList.cpp relating to that.

1 Like
2

Keys in the Resolvers are garbage collected after moving out of the MVCC window:

At Resolver, it calls:

		conflictBatch.detectConflicts(
		    req.version, req.version - SERVER_KNOBS->MAX_WRITE_TRANSACTION_LIFE_VERSIONS, commitList, &tooOldList);

The second parameter is the oldest version to be kept in the skip list. In the SkipList.cpp, the garbage collection code is:

	if (newOldestVersion > cs->oldestVersion) {
		cs->oldestVersion = newOldestVersion;
		SkipList::Finger finger;
		int temp;
		cs->versionHistory.find(&cs->removalKey, &finger, &temp, 1);
		cs->versionHistory.removeBefore(cs->oldestVersion, finger, combinedWriteConflictRanges.size() * 3 + 10);
		cs->removalKey = finger.getValue();
	}
2 Likes