Quick Peek into “Watchdog” Table

(inside the drupal database)

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The watchdog table is Drupal’s system log table. It stores runtime messages generated by Drupal core, (contributed/custom) modules and themes—things like cron activity, errors, warnings, notices, and user actions.

What Each Column in Watchdog Table Means ?

  • wid: Unique ID for each log entry.
  • uid: The user ID responsible for the action. (0 = system / anonymous)
  • type: The source module or category of the message. (For instance: cron → Drupal cron job, webform → Webform module, user → User login/session activity, access denied → Permission issues, php → PHP-level log)
  • message: The log message itself (Often contains placeholders like: @module, %time, @form in their code, which gets replaced at runtime using variables stored in the variable column)
  • variable: To store variables/placeholder such as @module, %time, @form mentioned previously (Serialized data (BLOB))

Watchdog Logs in Drupal Backend

In the admin UI, this data appears as Reports → Recent log messages (/admin/reports/dblog)

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Drupal Logging API

You can use the Drupal Logger API to log message into the watchdog table

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// Logs a notice
\Drupal::logger('my_module')->notice($message);

// Logs an error
\Drupal::logger('my_module')->error($message);

// Other functions (enumerated in Drupal\Core\Logger\RfcLoggerTrait)
\Drupal::logger('my_module')->emergency($message, $context);
\Drupal::logger('my_module')->alert($message, $context);
\Drupal::logger('my_module')->critical($message, $context);
\Drupal::logger('my_module')->warning($message, $context);
\Drupal::logger('my_module')->notice($message, $context);
\Drupal::logger('my_module')->info($message, $context);
\Drupal::logger('my_module')->debug($message, $context);

Alternatively, you can also use loggerFactory to create a logger instance that register to certain channel (message $type), below is an example, of how the Drupal core mail modules uses logger to log message into “mail” channel:

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Drush Watchdog Command

Drush provides powerful commands for managing Drupal’s watchdog logs, primarily drush watchdog:show(or ws) for viewing recent logs with filtering by count, severity, or type, and drush watchdog:tail (or wt) for real-time monitoring, similar to tail -f, with options for filtering and extended details, plus drush watchdog:delete to clear log entries, all crucial for debugging and site maintenance.

  • drush watchdog:list: interactively filter the watchdog message listing

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    > drush watchdog:list

 ┌ Select a message type or severity level ─────────────────────┐
 │   ○ == message types ==                                    ┃ │
 │   ○ access denied                                          │ │
 │   ○ content                                                │ │
 │ › ● cron                                                   │ │
 │   ○ page not found                                         │ │
 │   ○ php                                                    │ │
 │   ○ user                                                   │ │
 │   ○ == severity levels ==                                  │ │
 │   ○ Emergency                                              │ │
 │   ○ Alert                                                  │ │
 └──────────────────────────────────────────────────────────────┘

 > <enter>

 ┌ Select a message type or severity level ─────────────────────┐
 │ cron                                                         │
 └──────────────────────────────────────────────────────────────┘

 ------ -------------- ------ ---------- ----------------------------------------------------------------------------------
  ID     Date           Type   Severity   Message
 ------ -------------- ------ ---------- ----------------------------------------------------------------------------------
  5527   13/Jan 13:28   cron   Info       Cron run completed.
  5526   13/Jan 13:28   cron   Info       Execution of update_cron() took 872.52ms.
  5525   13/Jan 13:28   cron   Info       Starting execution of update_cron(), execution of system_cron() took 184.09ms.
  5524   13/Jan 13:28   cron   Info       Starting execution of system_cron(), execution of search_cron() took 11394.97ms.
  5523   13/Jan 13:27   cron   Warning    Attempting to re-run cron while it is already running.
  5522   13/Jan 13:27   cron   Warning    Attempting to re-run cron while it is already running.
  5521   13/Jan 13:27   cron   Warning    Attempting to re-run cron while it is already running.
  5520   13/Jan 13:27   cron   Info       Starting execution of search_cron(), execution of node_cron() took 11.94ms.
  5519   13/Jan 13:27   cron   Info       Starting execution of node_cron(), execution of history_cron() took 0.54ms.
  5518   13/Jan 13:27   cron   Info       Starting execution of history_cron(), execution of file_cron() took 13.44ms.
 ------ -------------- ------ ---------- ----------------------------------------------------------------------------------

  • drush watchdog:tail: tail (monitor/watch) watchdog message

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    > drush watchdog:tail

    5527    13/Jan 13:28    cron    Info    Cron run completed.
    5526    13/Jan 13:28    cron    Info    Execution of update_cron() took 872.52ms.
    5525    13/Jan 13:28    cron    Info    Starting execution of update_cron(), execution of system_cron() took 184.09ms.
    5524    13/Jan 13:28    cron    Info    Starting execution of system_cron(), execution of search_cron() took 11394.97ms.
    5523    13/Jan 13:27    cron    Warning Attempting to re-run cron while it is already running.
    5522    13/Jan 13:27    cron    Warning Attempting to re-run cron while it is already running.
    5521    13/Jan 13:27    cron    Warning Attempting to re-run cron while it is already running.
    5520    13/Jan 13:27    cron    Info    Starting execution of search_cron(), execution of node_cron() took 11.94ms.
    5519    13/Jan 13:27    cron    Info    Starting execution of node_cron(), execution of history_cron() took 0.54ms.
    5518    13/Jan 13:27    cron    Info    Starting execution of history_cron(), execution of file_cron() took 13.44ms.

(Now run 2026-01-13T15:43:00 run cron job ... get more logs !)

    5528    13/Jan 15:43    user    Info    Session opened for admin.
    5540    13/Jan 15:43    cron    Info    Cron run completed.
    5539    13/Jan 15:43    cron    Info    Execution of update_cron() took 579.71ms.
    5538    13/Jan 15:43    cron    Info    Starting execution of update_cron(), execution of system_cron() took 44.81ms.
    5537    13/Jan 15:43    cron    Info    Starting execution of system_cron(), execution of search_cron() took 42.43ms.
    5536    13/Jan 15:43    cron    Info    Starting execution of search_cron(), execution of node_cron() took 10.26ms.
    5535    13/Jan 15:43    cron    Info    Starting execution of node_cron(), execution of history_cron() took 0.25ms.
    5534    13/Jan 15:43    cron    Info    Starting execution of history_cron(), execution of file_cron() took 7.24ms.
    5533    13/Jan 15:43    cron    Info    Starting execution of file_cron(), execution of field_cron() took 2.34ms.
    5532    13/Jan 15:43    cron    Info    Starting execution of field_cron(), execution of dblog_cron() took 2.37ms.
    5531    13/Jan 15:43    cron    Info    Starting execution of dblog_cron(), execution of comment_cron() took 11.25ms.
    5530    13/Jan 15:43    cron    Info    Starting execution of comment_cron(), execution of announcements_feed_cron() took 1.12ms.
    5529    13/Jan 15:43    cron    Info    Starting execution of announcements_feed_cron().

(Continue monitoring for new logs ...)

  • drush watchdog:show-one: show one log record of certain ID

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    > drush watchdog:show-one 5527        # show log of ID 5527

    wid: '5527'
    uid: '0'
    type: cron
    message: 'Cron run completed.'
    severity: Info
    location: 'https://stage.opctest.com.au/apple-touch-icon-precomposed.png'
    hostname: 220.245.32.230
    date: '13/Jan 13:28'
    username: Anonymous

  • drush watchdog:show: show a listing of most recent 10 messages

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    > drush watchdog:show                         # show a listing of most recent 10 messages
> drush watchdog:show --count=123             # show a listing of most recent 123 messages
> drush watchdog:show --type=php              # show a listing of 10 recent php logs 
> drush watchdog:show --severity=Notice       # show a listing of 10 recent Notice logs
> drush watchdog:show --severity-min=Warning  # show a listing of most recent 10 messages with a severity of warning or higher.

Reference