private void load(final ConfigurationManager confManager) {
        checkState();
        try (final RocksIterator it = this.db.newIterator(this.confHandle, this.totalOrderReadOptions)) {
            it.seekToFirst();
            while (it.isValid()) {
                final byte[] ks = it.key();
                final byte[] bs = it.value();

                // LogEntry index
                if (ks.length == 8) {
                    final LogEntry entry = this.logEntryDecoder.decode(bs);
                    if (entry != null) {
                        if (entry.getType() == EntryType.ENTRY_TYPE_CONFIGURATION) {
                            final ConfigurationEntry confEntry = new ConfigurationEntry();
                            confEntry.setId(new LogId(entry.getId().getIndex(), entry.getId().getTerm()));
                            confEntry.setConf(new Configuration(entry.getPeers(), entry.getLearners()));
                            if (entry.getOldPeers() != null) {
                                confEntry.setOldConf(new Configuration(entry.getOldPeers(), entry.getOldLearners()));
                            }
                            if (confManager != null) {
                                confManager.add(confEntry);
                            }
                        }
                    } else {
                        LOG.warn("Fail to decode conf entry at index {}, the log data is: {}.", Bits.getLong(ks, 0),
                            BytesUtil.toHex(bs));
                    }
                } else {
                    if (Arrays.equals(FIRST_LOG_IDX_KEY, ks)) {
                        setFirstLogIndex(Bits.getLong(bs, 0));
                        truncatePrefixInBackground(0L, this.firstLogIndex);
                    } else {
                        LOG.warn("Unknown entry in configuration storage key={}, value={}.", BytesUtil.toHex(ks),
                            BytesUtil.toHex(bs));
                    }
                }
                it.next();
            }
        }
    }
First log index and last log index key in configuration column family.
jraft-core/src/main/java/com/alipay/sofa/jraft/storage/impl/RocksDBLogStorage.java