void WiredTigerSession::releaseCursor(uint64_t id, WT_CURSOR* cursor) {
invariant(_session);
invariant(cursor);
_cursorsOut--;
invariantWTOK(cursor->reset(cursor));
// Cursors are pushed to the front of the list and removed from the back
_cursors.push_front(WiredTigerCachedCursor(id, _cursorGen++, cursor));
// A negative value for wiredTigercursorCacheSize means to use hybrid caching.
std::uint32_t cacheSize = abs(kWiredTigerCursorCacheSize.load());
while (!_cursors.empty() && _cursorGen - _cursors.back()._gen > cacheSize) {
cursor = _cursors.back()._cursor;
_cursors.pop_back();
invariantWTOK(cursor->close(cursor));
}
}
void WiredTigerSession::releaseCursor(uint64_t id, WT_CURSOR* cursor) {
invariant(_session);
invariant(cursor);
_cursorsOut--;
invariantWTOK(cursor->reset(cursor));
// Cursors are pushed to the front of the list and removed from the back
_cursors.push_front(WiredTigerCachedCursor(id, _cursorGen++, cursor));
_cursorsCached++;
// "Old" is defined as not used in the last N**2 operations, if we have N cursors cached.
// The reasoning here is to imagine a workload with N tables performing operations randomly
// across all of them (i.e., each cursor has 1/N chance of used for each operation). We
// would like to cache N cursors in that case, so any given cursor could go N**2 operations
// in between use.
while (_cursorGen - _cursors.back()._gen > 10000) {
cursor = _cursors.back()._cursor;
_cursors.pop_back();
_cursorsCached--;
invariantWTOK(cursor->close(cursor));
}
}
