MySQL jobs table always keep one key

[lkebin]

Today, I got error notification from system about GEARMAN_TIMEOUT.

When I check gearmand log, found the following message:

  ERROR 2018-02-26 09:02:10.000000 [  proc ] mysql_stmt_execute failed: Duplicate entry '91d919b4-1ad1-11e8-80c4-00163e0e0072-HotelPriceCalculator::updat' for key 'unique_key' -> libgearman-server/plugins/queue/mysql/queue.cc:357
  ERROR 2018-02-26 09:02:10.000000 [  proc ] gearman_server_job_add gearman_server_run_command(QUEUE_ERROR) -> libgearman-server/server.cc:301
WARNING 2018-02-26 09:02:10.000000 [  proc ] GEARMAN_QUEUE_ERROR:QUEUE_ERROR -> libgearman-server/server.cc:302

Then, I check the gearman_jobs table (I'm using MySQL as queue), The unique key 91d919b4-1ad1-11e8-80c4-00163e0e0072 always stay there.

I tried restart gearmand and workers, the key still there.

What happen ?

[p-alik]

Does the table contain an unique key for values of unique_key.
create table statement I tested doesn't contain such constrain.

Then, I check the gearman_jobs table (I'm using MySQL as queue), The unique key 91d919b4-1ad1-11e8-80c4-00163e0e0072 always stay there.

I tried restart gearmand and workers, the key still there.

Is there active worker waiting for the job? I guess no.

[lkebin]

Yes, I restarted workers.

When I stop all workers, the gearman_jobs table will be include new jobs records, then start workers those jobs will be delete. but 91d919b4-1ad1-11e8-80c4-00163e0e0072 always be there.

[p-alik]

I can't explain what happened to this particular job. By putting jobs into the queue after restart gearmand takes all jobs. The jobs will be deleted if they are done. The only guess I've this particular job couldn't be successfully finished for some reason.

[lkebin]

I tried stop workers, then watch the jobs list table. Same function_name and data ({"product_id": 837}), but the first row will be there after start workers.

+--------------------------------------+---------------------------------------+----------+---------------------+-------------+
| unique_key                           | function_name                         | priority | data                | when_to_run |
+--------------------------------------+---------------------------------------+----------+---------------------+-------------+
| 91d919b4-1ad1-11e8-80c4-00163e0e0072 | ********************::updateDataCache |        1 | {"product_id":837}  |           0 |
| de35ce7a-1b8e-11e8-a8b3-00163e08037b | ********************::updateDataCache |        1 | {"product_id":837}  |           0 |
| df926a76-1b8e-11e8-9be2-00163e0e0072 | ********************::updateDataCache |        1 | {"product_id":551}  |           0 |
| dff83cca-1b8e-11e8-9217-00163e0e0072 | ********************::updateDataCache |        1 | {"product_id":551}  |           0 |
| e1354858-1b8e-11e8-8a18-00163e08037b | ********************::updateDataCache |        1 | {"product_id":837}  |           0 |
| e2329602-1b8e-11e8-a1fd-00163e0e0072 | ********************::updateDataCache |        1 | {"product_id":38}   |           0 |
| e2f5cffa-1b8e-11e8-9b38-00163e0e0072 | ********************::updateDataCache |        1 | {"product_id":1745} |           0 |
| e3462298-1b8e-11e8-b11c-00163e0e0072 | ********************::updateDataCache |        1 | {"product_id":1378} |           0 |
+--------------------------------------+---------------------------------------+----------+---------------------+-------------+