insert-segment-to-db is a tool that can insert segments into Druid metadata storage. It is intended to be used
to update the segment table in metadata storage after people manually migrate segments from one place to another.
It can also be used to insert missing segment into Druid, or even recover metadata storage by telling it where the
segments are stored.
Note: This tool expects users to have Druid cluster running in a "safe" mode, where there are no active tasks to interfere the segments being inserted. Users can optionally bring down the cluster to make 100% sure nothing is interfering.
In order to make it work, user will have to provide metadata storage credentials and deep storage type through Java JVM argument or runtime.properties file. Specifically, this tool needs to know
Besides the properties above, you also need to specify the location where the segments are stored and whether you want to update descriptor.json. These two can be provided through command line arguments.
The directory URI where segments are stored. This tool will recursively look for segments underneath this directory and insert/update these segments in metdata storage. Attention: workingDir must be a complete URI, which means it must be prefixed with scheme type. For example, hdfs://hostname:port/segment_directory
if set to true, this tool will update `loadSpec` field in `descriptor.json` if the path in `loadSpec` is different from where `desciptor.json` was found. Default value is `true`.
Note: you will also need to load different Druid extensions per the metadata and deep storage you use. For example, if you
mysql as metadata storage and
HDFS as deep storage, you should load
Suppose your metadata storage is
mysql and you've migrated some segments to a directory in HDFS, and that directory looks
Directory path: /druid/storage/wikipedia ├── 2013-08-31T000000.000Z_2013-09-01T000000.000Z │ └── 2015-10-21T22_07_57.074Z │ └── 0 │ ├── descriptor.json │ └── index.zip ├── 2013-09-01T000000.000Z_2013-09-02T000000.000Z │ └── 2015-10-21T22_07_57.074Z │ └── 0 │ ├── descriptor.json │ └── index.zip ├── 2013-09-02T000000.000Z_2013-09-03T000000.000Z │ └── 2015-10-21T22_07_57.074Z │ └── 0 │ ├── descriptor.json │ └── index.zip └── 2013-09-03T000000.000Z_2013-09-04T000000.000Z └── 2015-10-21T22_07_57.074Z └── 0 ├── descriptor.json └── index.zip
To load all these segments into
mysql, you can fire the command below,
java -Ddruid.metadata.storage.type=mysql -Ddruid.metadata.storage.connector.connectURI=jdbc\:mysql\://localhost\:3306/druid -Ddruid.metadata.storage.connector.user=druid -Ddruid.metadata.storage.connector.password=diurd -Ddruid.extensions.loadList=[\"mysql-metadata-storage\",\"druid-hdfs-storage\"] -Ddruid.storage.type=hdfs -cp $DRUID_CLASSPATH io.druid.cli.Main tools insert-segment-to-db --workingDir hdfs://host:port//druid/storage/wikipedia --updateDescriptor true
In this example,
mysql and deep storage type are provided through Java JVM arguments, you can optionally put all
of them in a runtime.properites file and include it in the Druid classpath. Note that we also include
druid-hdfs-storage in the extension list.
After running this command, the segments table in
mysql should store the new location for each segment we just inserted.
Note that for segments stored in HDFS, druid config must contain core-site.xml as described in Druid Docs, as this new location is stored with relative path.