Installing application in Plesk from Application Vault or via CLI hangs at 0%

Symptoms

• When installing or updating (if already installed) an application like WordPress either from Tools and Settings > Application Vault or from Domains > example.com > Applications a progress bar is shown but never changes from 0%

• Checking the longtasks table in the database, stuck tasks can be seen: 

  # plesk db “select * from longtasks where status <> ‘done'”
  +———————+—-+————–+———+—————–+———+—————-+—————-+————-+—————+———————+—–+————+
  | startTime | id | type | status | statusProcessed | context | progressStatus | progressParams | progressMax | progressValue | finishTime | pid | externalId |
  +———————+—-+————–+———+—————–+———+—————-+—————-+————-+—————+———————+—–+————+
  | 2018-11-06 17:37:04 | 76 | aps-download | started | 0 | NULL | queue | NULL | 100 | 0 | 0000-00-00 00:00:00 | 0 | NULL |
  | 2018-11-06 17:37:05 | 77 | aps-download | started | 0 | NULL | queue | NULL | 100 | 0 | 0000-00-00 00:00:00 | 0 | NULL |
  +———————+—-+————–+———+—————–+———+—————-+—————-+————-+—————+———————+—–+————+

• Trying to work with applications through CLI such as downloading a package can be executed successfully but the process does does not finish:

  # plesk bin aps -d -package-name mediawiki
  The task to download APS package started. Task id: 77

  # plesk bin aps -g 77
  The task is in progress.
  total: 100
  completed: 0
  The task is current.

Cause

Stuck tasks in the
psa.longtasks
table.

Resolution

1. Connect to the server via SSH or via RDP

2. Backup the
psa
database by following the instructions form the article How to backup/restore a Plesk database dump?

3. Log into MySQL and access the
psa
database:

   # plesk db

4. Delete stuck long tasks tasks:

   MYSQL_LIN: mysql> delete from longtasks where status <> ‘done’;