Method RemoveSpansBefore

src/brpc/span.cpp:808–848

NOTE: may take more than 100ms

// NOTE: may take more than 100ms
leveldb::Status SpanDB::RemoveSpansBefore(int64_t tm) {
    if (id_db == NULL || time_db == NULL) {
        return leveldb::Status::InvalidArgument(leveldb::Slice("NULL param"));
    }
    leveldb::Status rc;
    leveldb::WriteOptions options;
    options.sync = false;
    leveldb::Iterator* it = time_db->NewIterator(leveldb::ReadOptions());
    for (it->SeekToFirst(); it->Valid(); it->Next()) {
        if (it->key().size() != 8) {
            LOG(ERROR) << "Invalid key size: " << it->key().size();
            continue;
        }
        const int64_t realtime =
            ToLittleEndian((const uint32_t*)it->key().data());
        if (realtime >= tm) {  // removal is done.
            break;
        }
        BriefSpan brief;
        if (brief.ParseFromArray(it->value().data(), it->value().size())) {
            uint32_t key_data[4];
            ToBigEndian(brief.trace_id(), key_data);
            ToBigEndian(brief.span_id(), key_data + 2);
            leveldb::Slice key((char*)key_data, sizeof(key_data));
            rc = id_db->Delete(options, key);
            if (!rc.ok()) {
                LOG(ERROR) << "Fail to delete from id_db";
                break;
            }
        } else {
            LOG(ERROR) << "Fail to parse value";
        }
        rc = time_db->Delete(options, it->key());
        if (!rc.ok()) {
            LOG(ERROR) << "Fail to delete from time_db";
            break;
        }
    }
    delete it;
    return rc;
}

// Write span into leveldb.
void Span::dump_to_db() {