Package org.apache.iotdb.db.metadata.upgrade

Class MetadataUpgrader

java.lang.Object

org.apache.iotdb.db.metadata.upgrade.MetadataUpgrader

public class MetadataUpgrader
extends java.lang.Object

IoTDB after v0.13 only support upgrade from v0.12x. This class implements the upgrade program.

Method Summary

Modifier and Type	Method	Description
boolean	clearEnvBeforeUpgrade()
void	clearOldFiles()
void	redoMLog()
void	reloadMetadataFromSnapshot()
static void	upgrade()	There are at most four files of old versions: snapshot: store the base MTree mlog: store the metadata operations based on the exising metadata stored in snapshot tag file: store the tag info of timeseries and snapshot and mlog both may hold offsets pointing to some part of this file tmp snapshot: a tmp file generated during the process of creating snapshot; this file is useless

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

upgrade

public static void upgrade()
                    throws java.io.IOException

There are at most four files of old versions:

1. snapshot: store the base MTree
2. mlog: store the metadata operations based on the exising metadata stored in snapshot
3. tag file: store the tag info of timeseries and snapshot and mlog both may hold offsets pointing to some part of this file
4. tmp snapshot: a tmp file generated during the process of creating snapshot; this file is useless

The purpose of upgrader is to recover metadata from the existing files and split and store them into files in certain storage group dirs. The upgrader will execute the following steps in order:

1. Deserialize the snapshot and recover the MRTree into memory
2. Try set storage group based on the recovered StorageGroupMNodes and create timeseries based on the recovered MeasurementMNode
3. Redo the mlog
4. rename and backup the files in the same directory, the order is:
   1. mlog.bin to mlog.bin.bak
   2. mtree-1.snapshot.bin to mtree-1.snapshot.bin.bak
   3. tlog.txt to tlog.txt.bak
   4. mtree-1.snapshot.bin.tmp to mtree-1.snapshot.bin.tmp.bak

Throws:

java.io.IOException

clearEnvBeforeUpgrade

public boolean clearEnvBeforeUpgrade()
                              throws java.io.IOException

Throws:

java.io.IOException

clearOldFiles

public void clearOldFiles()
                   throws java.io.IOException

Throws:

java.io.IOException

reloadMetadataFromSnapshot

public void reloadMetadataFromSnapshot()
                                throws java.io.IOException

Throws:

java.io.IOException

redoMLog

public void redoMLog()
              throws java.io.IOException

Throws:

java.io.IOException