Changes

With {{Version|9.0}} of BaseX, jobs A job can 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}} and {{Function|Jobs|jobs:invoke}}:

(: register job, which as service; will be run every day at 1 am :)

'''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services will be scheduled for evaluation when the BaseX server or BaseX HTTP server is started.* If a job service is outdated (e.g. because a supplied end time has been exceeded), it will be removed from the jobs file at startup time.

* <code>state</code>: current state of the job (: <code>scheduled</code>, <code>queued</code>, <code>running</code>, or <code>cached)</code>* <code>user</code>: the user who started the job* <code>duration</code>: evaluation time (for included if a job is running and or if the result was cached jobs)* <code>start</code>: dateTime string with next start of job (for jobs that included if a job will be executed repeatedly)* <code>time</code>: time when job was registered

|{{Func|jobs:servicesfinished|$id as xs:string|element(job)*xs:boolean}}

|Returns a list Indicates if the evaluation of all jobs that have been persistently registered as [[#Services|Services]].|-| '''Errors'''|an already running job with the specified {{ErrorCode|services|#Errors$id}} Registered services cannot has finished. As the ids of finished jobs will usually be parseddiscarded, unless caching is enabled, the function will also return <code>true</code> for unknown jobs.* <code>false<br/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:finishedservices==

|{{Func|jobs:finishedservices|$id as xs:string|xs:booleanelement(job)*}}

|Indicates if the evaluation Returns a list of an already running job with the specified all jobs that have been persistently registered as [[#Services|Services]].|-| '''Errors'''|{{CodeError|$idservices|#Errors}} has finished. As the ids of finished jobs will usually Registered services cannot be discarded, unless caching is enabled, the function will also return <code>true</code> for unknown jobsparsed.* <code>false<br/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).

Asynchronous query execution is recommendable if There are cases in which a client does not, or cannot, wait until a request is fully processed. This is e. g. the case with web browsersThe client may be a browser, which will usually cancel a sends an HTTP request after a specific timeout. In such cases, you can use asynchronous execution to trigger another the server-side process, which will in order to start the another time-consuming processquery job. The functions in this section allow you to register a new query job from a running query. Jobs can be executed immediately (i.e., and fetch the result later on as soon as the [[Transaction Management#Concurrency Control|Concurrency Control]] allows it is available) or scheduled for repeated execution. Each registered job gets a job id, and the id can be used to retrieve a query result, stop a job, or wait for its termination.

|{{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 />

|Schedules the evaluation of the supplied {{Code|$query}} and returns a query id. The query will be queued, and the result will optionally be cached. Queries can be updating. Variables The query can be a URI or a string, and variables and context items can be declared via {{Code|$bindings}} (see [[XQuery Module#xquery:eval|xquery:eval]] for more details). The following {{Code|$options}} can be supplied:

* {{Code|service}}: additionally registers the job as [[#Services|Serviceservice]]. Registered services must have no variable bindings.

* The query in the specified file will be evaluated once:<pre class='brush:xquery'>jobs:eval(xs:anyURI('cleanup.xq'))</pre>* The following expression, if stored as in a file, calls and evaluates itself will be evaluated every 5 seconds:

file:read-text(static-base-uri()),

* 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):

let $query := jobs:eval('(1 to 10000000)[. = 1]', map{}, map{ 'cache': true() })

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.