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Job manager and the JOB statements

The long-term tasks run by the Storage Service are called jobs, such as COMPACT, FLUSH, and STATS. These jobs can be time-consuming if the data amount in the graph space is large. The job manager helps you run, show, stop, and recover jobs.

Note

All job management commands can be executed only after selecting a graph space.

SUBMIT JOB COMPACT

The SUBMIT JOB COMPACT statement triggers the long-term RocksDB compact operation in the current graph space.

For more information about compact configuration, see Storage Service configuration.

For example:

nebula> SUBMIT JOB COMPACT;
+------------+
| New Job Id |
+------------+
| 40         |
+------------+

SUBMIT JOB FLUSH

The SUBMIT JOB FLUSH statement writes the RocksDB memfile in the memory to the hard disk in the current graph space.

For example:

nebula> SUBMIT JOB FLUSH;
+------------+
| New Job Id |
+------------+
| 96         |
+------------+

SUBMIT JOB STATS

The SUBMIT JOB STATS statement starts a job that makes the statistics of the current graph space. Once this job succeeds, you can use the SHOW STATS statement to list the statistics. For more information, see SHOW STATS.

Note

If the data stored in the graph space changes, in order to get the latest statistics, you have to run SUBMIT JOB STATS again.

For example:

nebula> SUBMIT JOB STATS;
+------------+
| New Job Id |
+------------+
| 9          |
+------------+

SUBMIT JOB DOWNLOAD/INGEST

The SUBMIT JOB DOWNLOAD HDFS and SUBMIT JOB INGEST commands are used to import the SST file into NebulaGraph. For detail, see Import data from SST files.

The SUBMIT JOB DOWNLOAD HDFS command will download the SST file on the specified HDFS.

The SUBMIT JOB INGEST command will import the downloaded SST file into NebulaGraph.

For example:

nebula> SUBMIT JOB DOWNLOAD HDFS "hdfs://192.168.10.100:9000/sst";
+------------+
| New Job Id |
+------------+
| 10         |
+------------+
nebula> SUBMIT JOB INGEST;
+------------+
| New Job Id |
+------------+
| 11         |
+------------+

SHOW JOB

The Meta Service parses a SUBMIT JOB request into multiple tasks and assigns them to the nebula-storaged processes. The SHOW JOB <job_id> statement shows the information about a specific job and all its tasks in the current graph space.

job_id is returned when you run the SUBMIT JOB statement.

For example:

nebula> SHOW JOB 9;
+----------------+-----------------+------------+----------------------------+----------------------------+-------------+
| Job Id(TaskId) | Command(Dest)   | Status     | Start Time                 | Stop Time                  | Error Code  |
+----------------+-----------------+------------+----------------------------+----------------------------+-------------+
| 9              | "STATS"         | "FINISHED" | 2022-04-12T08:47:33.000000 | 2022-04-12T08:47:33.000000 | "SUCCEEDED" |
| 0              | "192.168.8.100" | "FINISHED" | 2022-04-12T08:47:33.000000 | 2022-04-12T08:47:34.000000 | "SUCCEEDED" |
| 1              | "192.168.8.101" | "FINISHED" | 2022-04-12T08:47:33.000000 | 2022-04-12T08:47:34.000000 | "SUCCEEDED" |
+----------------+-----------------+------------+----------------------------+----------------------------+-------------+

The descriptions are as follows.

Parameter Description
Job Id(TaskId) The first row shows the job ID and the other rows show the task IDs.
Command(Dest) The first row shows the command executed and the other rows show on which storaged processes the task is running.
Status Shows the status of the job or task. For more information, see Job status.
Start Time Shows a timestamp indicating the time when the job or task enters the RUNNING phase.
Stop Time Shows a timestamp indicating the time when the job or task gets FINISHED, FAILED, or STOPPED.
Error Code The error code of job.

Job status

The descriptions are as follows.

Status Description
QUEUE The job or task is waiting in a queue. The Start Time is empty in this phase.
RUNNING The job or task is running. The Start Time shows the beginning time of this phase.
FINISHED The job or task is successfully finished. The Stop Time shows the time when the job or task enters this phase.
FAILED The job or task has failed. The Stop Time shows the time when the job or task enters this phase.
STOPPED The job or task is stopped without running. The Stop Time shows the time when the job or task enters this phase.
REMOVED The job or task is removed.

The description of switching the status is described as follows.

Queue -- running -- finished -- removed
     \          \                /
      \          \ -- failed -- /
       \          \            /
        \ ---------- stopped -/

SHOW JOBS

The SHOW JOBS statement lists all the unexpired jobs in the current graph space.

The default job expiration interval is one week. You can change it by modifying the job_expired_secs parameter of the Meta Service. For how to modify job_expired_secs, see Meta Service configuration.

For example:

nebula> SHOW JOBS;
+--------+---------------------+------------+----------------------------+----------------------------+
| Job Id | Command             | Status     | Start Time                 | Stop Time                  |
+--------+---------------------+------------+----------------------------+----------------------------+
| 34     | "STATS"             | "FINISHED" | 2021-11-01T03:32:27.000000 | 2021-11-01T03:32:27.000000 |
| 33     | "FLUSH"             | "FINISHED" | 2021-11-01T03:32:15.000000 | 2021-11-01T03:32:15.000000 |
| 32     | "COMPACT"           | "FINISHED" | 2021-11-01T03:32:06.000000 | 2021-11-01T03:32:06.000000 |
| 31     | "REBUILD_TAG_INDEX" | "FINISHED" | 2021-10-29T05:39:16.000000 | 2021-10-29T05:39:17.000000 |
| 10     | "COMPACT"           | "FINISHED" | 2021-10-26T02:27:05.000000 | 2021-10-26T02:27:05.000000 |
+--------+---------------------+------------+----------------------------+----------------------------+

STOP JOB

The STOP JOB <job_id> statement stops jobs that are not finished in the current graph space.

For example:

nebula> STOP JOB 22;
+---------------+
| Result        |
+---------------+
| "Job stopped" |
+---------------+

RECOVER JOB

The RECOVER JOB [<job_id>] statement re-executes the jobs that status is QUEUE, FAILED or STOPPED in the current graph space and returns the number of recovered jobs. If <job_id> is not specified, re-execution is performed from the earliest job and the number of jobs that have been recovered is returned.

For example:

nebula> RECOVER JOB;
+-------------------+
| Recovered job num |
+-------------------+
| 5 job recovered   |
+-------------------+

FAQ

How to troubleshoot job problems?

The SUBMIT JOB operations use the HTTP port. Please check if the HTTP ports on the machines where the Storage Service is running are working well. You can use the following command to debug.

curl "http://{storaged-ip}:19779/admin?space={space_name}&op=compact"

Last update: September 16, 2022