Difference between revisions of "Job Module"
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* <code>jobs:list()</code> returns the same job id as [[#jobs:current|jobs:current]] if no other job is running. | * <code>jobs:list()</code> returns the same job id as [[#jobs:current|jobs:current]] if no other job is running. | ||
* <code>jobs:list()[. != jobs:current()] ! jobs:stop(.)</code> stops and invalidates all asynchronous queries and results except for the current one. | * <code>jobs:list()[. != jobs:current()] ! jobs:stop(.)</code> stops and invalidates all asynchronous queries and results except for the current one. | ||
+ | |} | ||
+ | |||
+ | ==jobs:list-details== | ||
+ | |||
+ | {| width='100%' | ||
+ | |- | ||
+ | | width='120' | '''Signatures''' | ||
+ | |{{Func|jobs:list-details||element(job)*}}<br/>{{Func|jobs:list-details|$id as xs:string|element(job)*}} | ||
+ | |- | ||
+ | | '''Summary''' | ||
+ | |Returns information on all jobs that are currently queued or executed. | ||
+ | |- | ||
+ | | '''Examples''' | ||
+ | | | ||
+ | * <code>jobs:list-details()</code> returns information on the currently running job and possibly others: | ||
+ | <pre class="brush:xml"> | ||
+ | <job id="job76" duration="PT0S" type="XQuery">XQUERY jobs:list-details()</job> | ||
+ | </pre> | ||
|} | |} | ||
Revision as of 17:45, 29 June 2016
This XQuery Module provides functions for organizing running commands and queries (…more to come).
Contents
Conventions
All functions in this module are assigned to the http://basex.org/modules/jobs
namespace, which is statically bound to the jobs
prefix. Errors will be bound to the same prefix.
Functions
jobs:current
Signatures | jobs:current() as xs:string
|
Summary | Returns the id of the current job. |
jobs:list
Signatures | jobs:list() as xs:string*
|
Summary | Returns the ids of all jobs that are currently queued or executed. |
Examples |
|
jobs:list-details
Signatures | jobs:list-details() as element(job)* jobs:list-details($id as xs:string) as element(job)*
|
Summary | Returns information on all jobs that are currently queued or executed. |
Examples |
<job id="job76" duration="PT0S" type="XQuery">XQUERY jobs:list-details()</job> |
jobs:finished
Signatures | jobs:finished($id as xs:string) as xs:boolean
|
Summary | Indicates if the evaluation of a job with the specified $id has finished:
|
jobs:stop
Signatures | jobs:stop($id as xs:string) as empty-sequence()
|
Summary | Cancels the execution of a job with the specified $id , or drops the cached result of a query. Unknown ids are ignored. All jobs are gracefully stopped; it is up to the process to decide when it is safe to shut down.
|
Asynchronous Execution
Asynchronous query execution is recommendable if a client does not, or cannot, wait until a request is fully processed. This is e. g. the case with web browsers, which will usually cancel a request after a specific timeout. In such cases, you can use asynchronous execution to trigger another server-side process, which will start the time-consuming process, and fetch the result later on as soon as it is available.
jobs:eval
Signatures | jobs:eval($query as xs:string) as xs:string jobs:eval($query as xs:string, $bindings as map(*)) as xs:string jobs:eval($query as xs:string, $bindings as map(*), $options as map(xs:string, xs:string)) as xs:string |
Summary | Prepares the supplied $query string for asynchronous execution and returns a query id. The query will be queued as described in the article on Transaction Management, and the result will be cached in main-memory until it is fetched via jobs:result, or until CACHETIMEOUT is exceeded. Queries may be updating.Variables and context items can be declared via $bindings (see xquery:eval for more details). The $options parameter contains evaluation options:
|
Errors | overflow : Too many queries or query results are queued. CACHETIMEOUT can be decreased if the default setting is too restrictive. |
Examples |
declare %rest:POST("{$query}") %rest:path('/eval') function local:eval($query) { jobs:eval($query) }; |
jobs:result
Signatures | jobs:result($id as xs:string) as item()*
|
Summary | Returns the cached result of a query with the specified job $id :
|
Errors | running : the query is still running.unknown : the supplied query id is unknown: The query result may already have been retrieved, or query execution may have been stopped. |
Examples |
declare %rest:path('/result/{$id}') function local:result($id) { jobs:result($id) };
let $query := jobs:eval('(1 to 10000000)[. = 1]') return ( hof:until( function($result) { jobs:finished($query) }, function($curr) { prof:sleep(10) }, () ), jobs:result($query) ) |
jobs:results
Signatures | jobs:results() as xs:string*
|
Summary | Returns the ids of all jobs for which results are cached. |
Errors
Code | Description |
---|---|
unknown
|
The supplied query id is unknown or not available anymore. |
running
|
A query is still running. |
overflow
|
Too many queries or query results are queued. |
Changelog
The module was introduced with Version 8.5.