private static void reinitializeStatics() {
      CONF = IoTDBDescriptor.getInstance().getConfig();
      INSTANCE =
          ConsensusFactory.getConsensusImpl(
                  CONF.getSchemaRegionConsensusProtocolClass(),
                  ConsensusConfig.newBuilder()
                      .setThisNodeId(CONF.getDataNodeId())
                      .setThisNode(
                          new TEndPoint(
                              CONF.getInternalAddress(), CONF.getSchemaRegionConsensusPort()))
                      .setConsensusGroupType(TConsensusGroupType.SchemaRegion)
                      .setRatisConfig(
                          RatisConfig.newBuilder()
                              .setSnapshot(
                                  RatisConfig.Snapshot.newBuilder()
                                      .setAutoTriggerThreshold(
                                          CONF.getSchemaRatisConsensusSnapshotTriggerThreshold())
                                      .build())
                              .setLog(
                                  RatisConfig.Log.newBuilder()
                                      .setUnsafeFlushEnabled(
                                          CONF.isSchemaRatisConsensusLogUnsafeFlushEnable())
                                      .setForceSyncNum(
                                          CONF.getSchemaRatisConsensusLogForceSyncNum())
                                      .setSegmentSizeMax(
                                          SizeInBytes.valueOf(
                                              CONF.getSchemaRatisConsensusLogSegmentSizeMax()))
                                      .setPreserveNumsWhenPurge(
                                          CONF.getSchemaRatisConsensusPreserveWhenPurge())
                                      .build())
                              .setGrpc(
                                  RatisConfig.Grpc.newBuilder()
                                      .setFlowControlWindow(
                                          SizeInBytes.valueOf(
                                              CONF.getSchemaRatisConsensusGrpcFlowControlWindow()))
                                      .setLeaderOutstandingAppendsMax(
                                          CONF
                                              .getSchemaRatisConsensusGrpcLeaderOutstandingAppendsMax())
                                      .build())
                              .setRpc(
                                  RatisConfig.Rpc.newBuilder()
                                      .setTimeoutMin(
                                          TimeDuration.valueOf(
                                              CONF
                                                  .getSchemaRatisConsensusLeaderElectionTimeoutMinMs(),
                                              TimeUnit.MILLISECONDS))
                                      .setTimeoutMax(
                                          TimeDuration.valueOf(
                                              CONF
                                                  .getSchemaRatisConsensusLeaderElectionTimeoutMaxMs(),
                                              TimeUnit.MILLISECONDS))
                                      .setRequestTimeout(
                                          TimeDuration.valueOf(
                                              CONF.getSchemaRatisConsensusRequestTimeoutMs(),
                                              TimeUnit.MILLISECONDS))
                                      .setSlownessTimeout(
                                          TimeDuration.valueOf(
                                              CONF.getSchemaRatisConsensusRequestTimeoutMs() * 6,
                                              TimeUnit.MILLISECONDS))
                                      .setFirstElectionTimeoutMin(
                                          TimeDuration.valueOf(
                                              CONF.getRatisFirstElectionTimeoutMinMs(),
                                              TimeUnit.MILLISECONDS))
                                      .setFirstElectionTimeoutMax(
                                          TimeDuration.valueOf(
                                              CONF.getRatisFirstElectionTimeoutMaxMs(),
                                              TimeUnit.MILLISECONDS))
                                      .build())
                              .setClient(
                                  RatisConfig.Client.newBuilder()
                                      .setClientRequestTimeoutMillis(
                                          CONF.getDataRatisConsensusRequestTimeoutMs())
                                      .setClientMaxRetryAttempt(
                                          CONF.getDataRatisConsensusMaxRetryAttempts())
                                      .setClientRetryInitialSleepTimeMs(
                                          CONF.getDataRatisConsensusInitialSleepTimeMs())
                                      .setClientRetryMaxSleepTimeMs(
                                          CONF.getDataRatisConsensusMaxSleepTimeMs())
                                      .setMaxClientNumForEachNode(CONF.getMaxClientNumForEachNode())
                                      .build())
                              .setImpl(
                                  RatisConfig.Impl.newBuilder()
                                      .setRaftLogSizeMaxThreshold(CONF.getSchemaRatisLogMax())
                                      .setForceSnapshotInterval(
                                          CONF.getSchemaRatisPeriodicSnapshotInterval())
                                      .setRetryTimesMax(10)
                                      .setRetryWaitMillis(CONF.getConnectionTimeoutInMS() / 10)
                                      .build())
                              .setLeaderLogAppender(
                                  RatisConfig.LeaderLogAppender.newBuilder()
                                      .setBufferByteLimit(
                                          CONF.getSchemaRatisConsensusLogAppenderBufferSizeMax())
                                      .build())
                              .setRead(
                                  RatisConfig.Read.newBuilder()
                                      .setReadOption(RatisConfig.Read.Option.LINEARIZABLE)
                                      // use thrift connection timeout to unify read timeout
                                      .setReadTimeout(
                                          TimeDuration.valueOf(
                                              CONF.getConnectionTimeoutInMS(),
                                              TimeUnit.MILLISECONDS))
                                      .build())
                              .build())
                      .setStorageDir(CONF.getSchemaRegionConsensusDir())
                      .build(),
                  gid ->
                      new SchemaRegionStateMachine(
                          SchemaEngine.getInstance().getSchemaRegion((SchemaRegionId) gid)))
              .orElseThrow(
                  () ->
                      new IllegalArgumentException(
                          String.format(
                              ConsensusFactory.CONSTRUCT_FAILED_MSG,
                              CONF.getSchemaRegionConsensusProtocolClass())));
    }
We can use SchemaRegionConsensusImpl.getInstance() to obtain a consensus layer reference for
schemaRegion's reading and writing
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/consensus/SchemaRegionConsensusImpl.java