Bureaucrats, editor, reviewer, Administrators
13,550
edits
Changes
Jump to navigation
Jump to search
Jobs can additionally be registered as persistent services. An additional {{Code|service}} option has been added to the options list of {{Function|Jobs|jobs:eval}} and {{Function|Jobs|jobs:invoke}}: <pre classsyntaxhighlight lang="brush:xquery">(: register job, which as service; will be run every day at 1 am :)
{| width='100%'|-| width='120' | '''Signatures'''|{{Func|jobs:list-details||element(job)*}}<br/>{{Func|jobs:list-details|$id as xs:string|element(job)*}}|-| '''Summary'''|Returns information on all jobs that There are currently registeredcases in which a client does not, or on cannot, wait until a job with the specified {{Code|$id}} (or an empty sequence if this job request is not found)fully processed. The list includes scheduledclient may be a browser, queued, running jobs, and cached jobs. A string representation of which sends an HTTP request to the server in order to start another time-consuming query job, or its URI, will be returned as value. The returned elements have additional attributes:* <code>id</code>: functions in this section allow you to register a new query job id* <code>type</code>: type of the job (command, from a running query, REST, RESTXQ, etc.)* <code>state</code>: current state of the job (scheduled, queued, running, or cached)* <code>user</code>: the user who started the job* <code>duration</code>: evaluation time (for running and cached jobs)* <code>start</code>: dateTime string with next start (for jobs that will Jobs can be executed repeatedly)|-| '''Examples'''| <code>jobs:list-detailsimmediately ()</code> returns information on the currently running job and possibly others:<pre class="brush:xml"><job id="job1" type="XQuery" state="running" user="admin" duration="PT0i.e.001S"> XQUERY jobs:list-details()</job></pre>|} {| width='100%'|-| width='120' | '''Signatures'''|{{Func|jobs:services||element(job)*}}|-| '''Summary'''|Returns a list of all jobs that have been persistently registered , as soon as the [[Transaction Management#ServicesConcurrency Control|ServicesConcurrency Control]]allows it) or scheduled for repeated execution.|-| '''Errors'''|{{Error|services|#Errors}} Registered services cannot be parsed.<br/>|} ==jobs:finished== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|jobs:finished|$id as xs:string|xs:boolean}}|-| '''Summary'''|Indicates if the evaluation of an already running Each registered job with the specified {{Code|$id}} has finished. As the ids of finished jobs will usually be discarded, unless caching is enabled, the function will also return <code>true</code> for unknown jobs.* <code>false</code> indicates that the gets a job id is scheduled, queued, or currently running.* <code>true</code> will be returned if the job has either finished, or if and the id is unknown (because the ids of all finished jobs will not can be cached).|} =Execution= Asynchronous used to retrieve a query execution is recommendable if result, stop a client does notjob, or cannot, wait until a request is fully processed. This is e. g. the case with web browsers, which will usually cancel a request after a specific timeout. In such cases, you can use asynchronous execution to trigger another server-side process, which will start the time-consuming process, and fetch the result later on as soon as it is availablefor its termination.
file:read-text(static-base-uri()),
==jobs{{Mark|Updated with Version 9.7:}} Return empty sequence if no result==is cached.
|-
|{{Code|unknown}}
| The supplied query id is unknown or not available anymore.
no edit summary
=Services=
A job can be registered as ''service'' by supplying the {{MarkCode|Introduced with Version 9.0service}} option to {{Function|Jobs|jobs:eval}}:
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.* Job services can be updated: If a new job service is registered, and if there is already outdated (e.g. because a job with the same idsupplied end time has been exceeded), the old entry it will be replacedremoved from the jobs file at startup time.
* The job definitions are stored in a {{Code|jobs.xml}} file in the database directory. It can also be edited manually.
=Basic Functions= ==jobs:current== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|jobs:current||xs:string}}|-| '''Summary'''|Returns the id of the current job.|} ==jobs:list== {| width='100%'|-| width='120' | '''Signatures'''|{{Func|jobs:list||xs:string*}}|-| '''Summary'''|Returns the ids of all jobs that are currently registered. The list includes scheduled, queued, running, stopped, and finished jobs with cached results.|-| '''Examples'''| <code>jobs:list()</code> returns the same job id as {{Function|Executing Jobs|jobs:current}} if no other job is registered.|} ==jobs:list-details==
==jobs:eval==
|-
| width='120' | '''Signatures'''
|{{Func|jobs:eval|$query as xs:stringanyAtomicItem|xs:string}}<br />{{Func|jobs:eval|$query as xs:stringanyAtomicItem, $bindings as map(*)?|xs:string}}<br />{{Func|jobs:eval|$query as xs:stringanyAtomicItem, $bindings as map(*)?, $options as map(*)?|xs:string}}<br />
|-
| '''Summary'''
|Schedules the evaluation of the supplied {{Code|$query}} ({{Code|xs:string}}, or of type {{Code|xs:anyURI}}, pointing to a resource), and returns a query id. The query will be queued, and the result will optionally be cached. Queries can be updating. Variables and the context items value can be declared via {{Code|$bindings}} (see [[XQuery Module#xquery:eval|xquery:eval]] for more details). The following {{Code|$options}} can be supplied:
* {{Code|cache}}: indicates if the query result will be cached or ignored (default: <code>false</code>):
** 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 the specified number is specifiedgreater than the elapsed 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(
map { },
map { 'start': 'PT5S' }
)
</presyntaxhighlight>
|}
==jobs:invokeresult== {{Mark|Introduced with Version 9.0:}} {| width='100%'|-| width='120' | '''Signatures'''|{{Func|jobs:invoke|$uri as xs:string|xs:string}}<br />{{Func|jobs:invoke|$uri as xs:string, $bindings as map(*)?|xs:string}}<br />{{Func|jobs:invoke|$uri as xs:string, $bindings as map(*)?, $options as map(*)?|xs:string}}<br />|-| '''Summary'''|Schedules the evaluation of the XQuery expression located at {{Code|$uri}} and returns a query id. For further details, see [[#jobs:eval|jobs:eval]].|-| '''Errors'''|{{Error|overflow|#Errors}} Query execution is rejected, because too many jobs are queued or being executed. {{Option|CACHETIMEOUT}} can be decreased if the default setting is too restrictive.<br/>{{Error|range|#Errors}} A specified time or duration is out of range.<br/>{{Error|id|#Errors}} The specified id is invalid or has already been assigned.<br/>{{Error|options|#Errors}} The specified options are conflicting.|-| '''Examples'''| Run XQuery expression that may perform some cleanups:<pre class='brush:xquery'>jobs:invoke("cleanup.xq", (), ())</pre>|}
{| width='100%'
| '''Summary'''
|Returns the cached result of a job with the specified job {{Code|$id}}:
* If the original job has raised an error, the cached error will be raised instead.
* Results can only be retrieved once. After retrieval, the cached result will be dropped.
* If the original job result has raised an error, the cached error will be raised instead.|-| '''Errors'''|{{Error|running|#Errors}} the job is still running.<br/>{{Error|unknown|#Errors}} the supplied id is unknown: The id is unknownalready been retrieved, or the result if it has already not been retrievedcached, an empty sequence is returned.<br/>
|-
| '''Examples'''
|
* The following [[RESTXQ]] function will either return the result of a previously started job or raise an error:
<pre classsyntaxhighlight lang='brush:"xquery'">
declare %rest:path('/result/{$id}') function local:result($id) {
jobs:result($id)
};
</presyntaxhighlight>* The following query demonstrates how the results of an asynchronously 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 $query := jobs:eval('(1 to 10000000)[. = 1]', map{}, map{ 'cache': true() })
return (
jobs:wait($query),
jobs:result($query)
)
</presyntaxhighlight>Please note that queries Queries of this kind can cause deadlocks. For example, if both ! If the original query and the new query to be executed asynchronously perform updates on the same database, the second query would will only be run after the first one has been executed, and the first query will wait for the second query forever. This is why you You should avoid this pattern in practice and resort to [[XQuery Module#xquery:fork-join|xquery:fork-join]] if you want to do things in have full control on parallelquery execution.
|}
| '''Errors'''
|{{Error|self|#Errors}} The current job is addressed.<br/>
|}
=Listing Jobs=
==jobs:current==
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|jobs:current||xs:string}}
|-
| '''Summary'''
|Returns the id of the current job.
|}
==jobs:list==
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|jobs:list||xs:string*}}
|-
| '''Summary'''
|Returns the ids of all jobs that are currently registered. The list includes scheduled, queued, running, stopped, and finished jobs with cached results.
|-
| '''Examples'''
| <code>jobs:list()</code> returns the same job id as {{Function|Jobs|jobs:current}} if no other job is registered.
|}
==jobs:list-details==
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|jobs:list-details||element(job)*}}<br/>{{Func|jobs:list-details|$id as xs:string|element(job)*}}
|-
| '''Summary'''
|Returns information on all jobs that are currently registered, or on a job with the specified {{Code|$id}} (or an empty sequence if this job is not found). The list includes scheduled, queued, running jobs, and cached jobs. A string representation of the job, or its URI, will be returned as value. The returned elements have additional attributes:
* <code>id</code>: job id
* <code>type</code>: type of the job (command, query, REST, RESTXQ, etc.)
* <code>state</code>: current state of the job: <code>scheduled</code>, <code>queued</code>, <code>running</code>, <code>cached</code>
* <code>user</code>: user who started the job
* <code>duration</code>: evaluation time (included if a job is running or if the result was cached)
* <code>start</code>: next start of job (included if a job will be executed repeatedly)
* <code>time</code>: time when job was registered
|-
| '''Examples'''
| <code>jobs:list-details()</code> returns information on the currently running job and possibly others:
<syntaxhighlight lang="xml">
<job id="job1" type="XQuery" state="running" user="admin" duration="PT0.001S">
XQUERY jobs:list-details()
</job>
</syntaxhighlight>
|}
==jobs:bindings==
{{Mark|Introduced with Version 10.0}}
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|jobs:bindings|$id as xs:string|map(*)}}
|-
| '''Summary'''
|Returns the variable bindings of an existing job with the specified {{Code|$id}}. If no variables have been bound to this job, an empty map is returned.
|}
==jobs:finished==
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|jobs:finished|$id as xs:string|xs:boolean}}
|-
| '''Summary'''
|Indicates if the evaluation of an already running job with the specified {{Code|$id}} has finished. As the ids of finished jobs will usually be discarded, unless caching is enabled, the function will also return <code>true</code> for unknown jobs.
* <code>false</code> indicates that the job id is scheduled, queued, or currently running.
* <code>true</code> will be returned if the job has either finished, or if the id is unknown (because the ids of all finished jobs will not be cached).
|}
==jobs:services==
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|jobs:services||element(job)*}}
|-
| '''Summary'''
|Returns a list of all jobs that have been persistently registered as [[#Services|Services]].
|-
| '''Errors'''
|{{Error|services|#Errors}} Registered services cannot be parsed.<br/>
|}
|{{Code|service}}
| Registered services cannot be parsed, added or removed.
|}
=Changelog=
;Version 10.0
* Added: {{Function|Jobs|jobs:bindings}}
;Version 9.7
* Updated: {{Function|Jobs|jobs:result}}: return empty sequence if no result is cached.
;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 {{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.
