Beispiel #1
0
Record SPSegment::lookup(TID tid) {
    // TODO assert(tid.getPage() is part of this segment);

    BufferFrame frame = bm->fixPage(tid.getPage(), false);
    SlottedPage* page = reinterpret_cast<SlottedPage*>(frame.getData());

    Slot* slot = page->getSlot(tid.getSlot());

    if (slot->isMoved()) {
        // Slot was indirected: Lookup that TID the slot points to recursively.
        bm->unfixPage(frame, false);
        return this->lookup(TID(slot->slot));
    } else if (slot->length() == 0 && slot->offset() == 0) {
        // Slot is empty: Return empty record
        bm->unfixPage(frame, false);
        return Record(0, nullptr);
    } else {
        // Slot has content: Return record with content.
        bm->unfixPage(frame, false);
        return Record(slot->length(), slot->getRecord()->getData());
    }
}
Beispiel #2
0
Record SPSegment::inPlaceLookup(TID tid) {
    // TODO assert(tid.getPage() is part of this segment);

    BufferFrame frame = bm->fixPage(tid.getPage(), false);
    SlottedPage* page = reinterpret_cast<SlottedPage*>(frame.getData());

    Slot* slot = page->getSlot(tid.getSlot());

    if (slot->isMoved() || slot->isEmpty()) {
        // Slot is empty: Return empty record
        bm->unfixPage(frame, false);
        return Record(0, nullptr);
    } else {
        // Slot has content: Return record with content.
        bm->unfixPage(frame, false);
        return Record(slot->length(), slot->getRecord()->getData());
    }
}