Method freeTombstoneObjects

src/snapshot.cpp:248–322

}

bool redisDbPersistentDataSnapshot::freeTombstoneObjects(int depth)
{
    if (m_pdbSnapshot == nullptr)
    {
        serverAssert(dictSize(m_pdictTombstone) == 0);
        return true;
    }

    if (!const_cast<redisDbPersistentDataSnapshot*>(m_pdbSnapshot)->freeTombstoneObjects(depth+1))
        return false;

    {
    AeLocker ae;
    ae.arm(nullptr);
    if (m_pdbSnapshot->m_refCount != depth && (m_pdbSnapshot->m_refCount != (m_refCount+1)))
        return false;
    ae.disarm();
    }

    std::unique_lock<fastlock> lock(s_lock, std::defer_lock);
    if (!lock.try_lock())
        return false; // this is a best effort function
    
    std::unique_ptr<LazyFree> splazy = std::make_unique<LazyFree>();

    dict *dictTombstoneNew = dictCreate(&dbTombstoneDictType, nullptr);
    dictIterator *di = dictGetIterator(m_pdictTombstone);
    dictEntry *de;
    std::vector<dictEntry*> vecdeFree;
    vecdeFree.reserve(dictSize(m_pdictTombstone));
    unsigned rgcremoved[2] = {0};
    while ((de = dictNext(di)) != nullptr)
    {
        dictEntry **dePrev = nullptr;
        dictht *ht = nullptr;
        sds key = (sds)dictGetKey(de);
        // BUG BUG: Why can't we do a shallow search here?
        dictEntry *deObj = dictFindWithPrev(m_pdbSnapshot->m_pdict, key, (uint64_t)dictGetVal(de), &dePrev, &ht, false);

        if (deObj != nullptr)
        {
            // Now unlink the DE
            __atomic_store(dePrev, &deObj->next, __ATOMIC_RELEASE);
            if (ht == &m_pdbSnapshot->m_pdict->ht[0])
                rgcremoved[0]++;
            else
                rgcremoved[1]++;
            splazy->vecde.push_back(deObj);
        } else {
            serverAssert(dictFind(m_pdbSnapshot->m_pdict, key) == nullptr);
            serverAssert(m_pdbSnapshot->find_cached_threadsafe(key) != nullptr);
            dictAdd(dictTombstoneNew, sdsdupshared((sds)dictGetKey(de)), dictGetVal(de));
        }
    }
    dictReleaseIterator(di);

    dictForceRehash(dictTombstoneNew);
    aeAcquireLock();