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=Services=
Jobs A job can additionally be registered as persistent services. An additional ''service'' by supplying the {{Code|service}} option has been added to the options list of {{Function|Jobs|jobs:eval}}:
<pre classsyntaxhighlight lang="brush:xquery">(: register job, which as service; will be run every day at 1 am :)
jobs:eval('db:drop("tmp")', (), map { 'id':'cleanup', 'start':'01:00:00', 'interval':'P1D', 'service': true() }),
(: unregister job :)
jobs:stop('cleanup', map { 'service': true() })
</presyntaxhighlight>
'''Some more notes:'''
* All registered jobs job services will be scheduled for evaluation when the BaseX server or BaseX HTTP server is started.
* If a job service is outdated (e.g. because a supplied end time has been exceeded), it will be removed from the jobs file at startup time.
* Job services can be updated: If a new job is registered, and if there is already a job with the same id, the old entry will be replaced.
* The job definitions are stored in a {{Code|jobs.xml}} file in the database directory. It can also be edited manually.
==jobs:list-details==
 
{{Mark|Updated with Version 9.1:}} registration time added
{| width='100%'
| '''Examples'''
| <code>jobs:list-details()</code> returns information on the currently running job and possibly others:
<pre classsyntaxhighlight lang="brush:xml">
<job id="job1" type="XQuery" state="running" user="admin" duration="PT0.001S">
XQUERY jobs:list-details()
</job>
</presyntaxhighlight>
|}
==jobs:eval==
{{Mark|Updated with Version 9.25}}: First argument can be a URI (jobs:invoke was removed)Integers added as valid start and end times.
{| width='100%'
** The result will be cached in main-memory until it is fetched via [[#jobs:result|jobs:result]], or until {{Option|CACHETIMEOUT}} is exceeded.
** If the query raises an error, it will be cached and returned instead.
* {{Code|start}}: a dayTimeDuration, time , dateTime or dateTime integer can be specified to delay the execution of the query:
** If a dayTimeDuration is specified, the query will be queued after the specified duration has passed. Examples for valid values are: <code>P1D</code> (1 day), <code>PT5M</code> (5 minutes), <code>PT0.1S</code> (100 ms). An error will be raised if a negative value is specified.
** If a dateTime is specified, the query will be executed at this date. Examples for valid values are: <code>2018-12-31T23:59:59</code> (New Year's Eve 2018, close to midnight). An error will be raised if the specified time lies in the past.
** If a time is specified, the query will be executed at this time of the day. Examples for valid times are: <code>02:00:00</code> (2am local time), <code>12:00:00Z</code> (noon, UTC). If the time lies in the past, the query will be executed the next day.
** An integer will be interpreted as minutes. If a dateTime is the specifiednumber exceeds the minutes of the current hour, the query will be executed at this date. Examples for valid values are: <code>2018-12-31T23:59:59</code> (New Year's Eve 2018, close to midnight). An error will be raised if the specified time lies in the pastone hour later.
* {{Code|interval}}: a dayTimeDuration string can be specified to execute the query periodically. An error is raised if the specified interval is less than one second (<code>PT1S</code>). If the next scheduled call is due, and if a query with the same id is still running, it will be skipped.
* {{Code|end}}: scheduling can be stopped after a given time or duration. The string format is the same as for {{Code|start}}. An error is raised if the resulting end time is smaller than the start time.
* {{Code|base-uri}}: sets the [https://www.w3.org/TR/xquery-31/#dt-static-base-uri base-uri property] for the query. This URI will be used when resolving relative URIs, such as with {{Code|fn:doc}}.
* {{Code|id}}: sets a custom job id. The id must not start with the standard <code>job</code> prefix, and it can only be assigned if no job with the same name exists.
* {{Code|service}}: additionally registers the job as [[#Services|service]]. Registered services must have no variable bindings.* {{Code|log}}: writes the specified string to the [[Logging|database logs]]. Two log entries are stored, one at the beginning and another one after the execution of the job.
|-
| '''Errors'''
|
* Cache query result. The returned id can be used to pick up the result with [[#jobs:result|jobs:result]]:
<pre classsyntaxhighlight lang='brush:"xquery'">
jobs:eval("1+3", (), map { 'cache': true() })
</presyntaxhighlight>
* A happy birthday mail will be sent at the given date:
<pre classsyntaxhighlight lang="brush:xquery">
jobs:eval("import module namespace mail='mail'; mail:send('Happy birthday!')",
(), map { 'start': '2018-09-01T06:00:00' })}}
</presyntaxhighlight>
* The following [[RESTXQ]] functions can be called to execute a query at 2 am every day. An id will be returned by the first function, which can be used to stop the scheduler via the second function:
<pre classsyntaxhighlight lang='brush:"xquery'">
declare %rest:POST("{$query}") %rest:path('/start-scheduling') function local:start($query) {
jobs:eval($query, (), map { 'start': '02:00:00', 'interval': 'P1D' })
jobs:stop($id)
};
</presyntaxhighlight>
* Query execution is scheduled for every second, and for 10 seconds in total. As the query itself will take 1.5 seconds, it will only be executed every second time:
<pre classsyntaxhighlight lang="brush:xquery">
jobs:eval("prof:sleep(1500)", (), map { 'interval': 'PT1S', 'end': 'PT10S' })
</presyntaxhighlight>* The query in the specified file will be evaluated once:<syntaxhighlight lang="xquery">jobs:eval(xs:anyURI('cleanup.xq'))</syntaxhighlight>* The following expression, if stored as in a file, calls and evaluates itself will be evaluated every 5 seconds:<pre classsyntaxhighlight lang="brush:xquery">
jobs:eval(
file:read-text(static-base-uri()),
map { },
map { 'start': 'PT5S' }
)
</pre>* Evaluate query in specified file:<pre class='brush:xquery'>jobs:eval(xs:anyURI('cleanup.xq'), (), ())</presyntaxhighlight>
|}
|
* The following [[RESTXQ]] function will either return the result of a previously started job or raise an error:
<pre classsyntaxhighlight lang='brush:"xquery'">
declare %rest:path('/result/{$id}') function local:result($id) {
jobs:result($id)
};
</presyntaxhighlight>
* The following query demonstrates how the results of an executed query can be returned within the same query (see below why you should avoid this pattern in practice):
<pre classsyntaxhighlight lang='brush:"xquery'">
let $query := jobs:eval('(1 to 10000000)[. = 1]', map { }, map { 'cache': true() })
return (
jobs:result($query)
)
</presyntaxhighlight>
Queries of this kind can cause deadlocks! If the original query and the new query perform updates on the same database, the second query will only be run after the first one has been executed, and the first query will wait for the second query forever. You should resort to [[XQuery Module#xquery:fork-join|xquery:fork-join]] if you want to have full control on parallel query execution.
|}
=Changelog=
 
;Version 9.5
* Updated: {{Function|Jobs|jobs:eval}}: integers added as valid start and end times.
 
;Version 9.4
* Updated: {{Function|Jobs|jobs:eval}}: option added for writing log entries.
* Updated: {{Function|Jobs|jobs:list-details}}: interval added.
;Version 9.2
 * Deleted: jobs:invoke (merged with [[#jobs:eval{{Function|Jobs|jobs:eval]]}})
;Version 9.1
 
* Updated: {{Function|Jobs|jobs:list-details}}: registration time added.
;Version 9.0
 
* Added: {{Function|Jobs|jobs:invoke}}, [[#Services|Services]]
;Version 8.6
 * Updated: [[#jobs:eval{{Function|Jobs|jobs:eval]]}}: <code>id</code> option added.
The module was introduced with Version 8.5.
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