job-queue | Enterprise queue solutions for PHP | Job Scheduling library
kandi X-RAY | job-queue Summary
kandi X-RAY | job-queue Summary
There is job queue component build on top of a transport. It provides some additional features like: unique job, sub jobs, dependent job and so. Read more about it in documentation.
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Top functions reviewed by kandi - BETA
- Process a message
- Save a job
- Run a unique job .
- Calculates the root job .
- Calculate the root job status .
- Run a delayed job
- Find or create a root job
- Find or create a child job
- Finds a job by id
- Save dependent jobs
job-queue Key Features
job-queue Examples and Code Snippets
Community Discussions
Trending Discussions on job-queue
QUESTION
I was wondering what happens when two transactions execute a SELECT ... FOR UPDATE query in parallel. The background is that I want to implement a job queue using SELECT ... FOR UPDATE with SKIP LOCKED, as shown here: https://vladmihalcea.com/database-job-queue-skip-locked/. But in this article the queries are quite trivial.
An example with two transactions T1 and T2 (transaction isolation level is set to READ_COMMITTED):
- T1 starts
- T1 executes
SELECT ... FOR UPDATE, searching for NEW rows, which requires some time. - T2 starts
- T2 executes
SELECT ... FOR UPDATEwith same WHERE clause and parameters as T1, which also takes some time. - T1 finally finds all rows, locks them
- T1 starts updating the rows (e.g. by marking them as now being IN_PROGRESS)
- T2 finally finds rows => what happens now?
Some questions:
- I would assume that T1 locks the rows in an atomic operation. Is this correct?
- So when T2 finally finds it's result set and tries to lock the rows it cannot do it? How does T2 react in this case? My assumption would be that it waits until T1 releases the locks (when not using NOWAIT).
- What if T2 finishes the query before T1 makes any changes (e.g. changing a job status from NEW to IN_PROGRESS)? Can both transaction find the same result set?
- If T1 somehow marks the locked rows (e.g. by changing a status column from NEW to IN_PROGRESS) and T2 looks for the original status (NEW), would T2 then, with
SKIP LOCKED, skip the marked rows? Will T2 re-evaluate it's result set after the changes made by T1?
ANSWER
Answered 2021-Apr-20 at 15:15Each transaction locks the rows as it finds them, so locking is not atomic. It could happen that T1 locks a couple of rows and T2 locks some other rows.
Since each transaction locks rows immediately when it finds them, this cannot happen. Either a row is locked, in which case it is skipped, or it is not locked, in which case it is locked.
If T1 commits before T2 is done scanning the table, T2 will happily lock all rows that were already processed by T1.
Yes, that will work. T2 will fetch the most current version of each row before it checks the condition and locks the row.
QUESTION
I'm trying to use Dask job-queue on our HPC system. And this is the code I'm using:
...ANSWER
Answered 2021-Apr-08 at 07:55The main problem is with an incorrect specification of shebang:
QUESTION
Please do correct me if I'm wrong about anything:
The JS runtime engine agents are driven by an event loop, which collects any user and other events, enqueuing tasks to handle each callback.
The event loop runs continuously and has the following thought process:
- Is the execution context stack (commonly referred to as the call stack) empty?
- If it is, then insert any microtasks in the microtask queue (or job queue) into the call stack. Keep doing this until the microtask queue is empty.
- If microtask queue is empty, then insert the oldest task from the task queue (or callback queue) into the call stack
So there are two key differences b/w how tasks and microtasks are handled:
- Microtasks (e.g. promises use microtask queue to run their callbacks) are prioritised over tasks (e.g. callbacks from othe web APIs such as setTimeout)
- Additionally, all microtasks are completed before any other event handling or rendering or any other task takes place. Thus, the application environment is basically the same between microtasks.
Promises were introduced in ES6 2015. I assume the microtask queue was also introduced in ES6.
My questionWhat was the motivation for introducing the microtask queue? Why not just keep using the task queue for promises as well?
Update #1 - I'm looking for a definite historical reason(s) for this change to the spec - i.e. what was the problem it was designed to solve, rather than an opinionated answer about the benefits of the microtask queue.
References:- In depth: Microtasks and the JavaScript runtime environment
- HTML spec event loop processing model
- Javascript-hard-parts-v2
- loupe - Visualisation tool to understand JavaScript's call stack/event loop/callback queue interaction
- Using microtasks in JavaScript with queueMicrotask()
ANSWER
Answered 2021-Feb-13 at 22:49One advantage is fewer possible differences in observable behavior between implementations.
If these queues weren't categorized, then there would be undefined behavior when determining how to order a setTimeout(..., 0) callback vs. a promise.then(...) callback strictly according to the specification.
I would argue that the choice of categorizing these queues into microtasks and "macro" tasks decreases the kinds of bugs possible due to race conditions in asynchronicity.
This benefit appeals particularly to JavaScript library developers, whose goal is generally to produce highly optimized code while maintaining consistent observable behavior across engines.
QUESTION
I'm using a SQL table as a job queue very similar to the article here: https://vladmihalcea.com/database-job-queue-skip-locked/
My problem is that I'm using Entity Framework 6 with Database First code and from what I can tell, EF6 doesnt' support the skip locked command. Here is my table class and I'm using each computer as a worker to handle the task I'm passing it.
...ANSWER
Answered 2021-Jan-27 at 08:13You can write custom queries in EF Core, see here. So you could do something like this:
QUESTION
Trying to follow GNU Parallel as job queue with named pipes with GNU parallel 20201222, I run into issues of parallel not executing the last commands piped into it via tail -n+0 -f.
To demonstrate, I have 3 terminals open:
...ANSWER
Answered 2021-Jan-13 at 13:40From man parallel:
There is a a small issue when using GNU parallel as queue system/batch manager: You have to submit JobSlot number of jobs before they will start, and after that you can submit one at a time, and job will start immediately if free slots are available. Output from the running or completed jobs are held back and will only be printed when JobSlots more jobs has been started (unless you use --ungroup or --line-buffer, in which case the output from the jobs are printed immediately). E.g. if you have 10 jobslots then the output from the first completed job will only be printed when job 11 has started, and the output of second completed job will only be printed when job 12 has started.
In other words: The jobs are running. Output is delayed. It is easier to see if you instead of using echo in your example use touch unique-file-name.
QUESTION
I've been running Airflow using helm chart. The object of airflow is to invoke AWS Batch Job in the DAGs like below.
...ANSWER
Answered 2020-Dec-01 at 09:09in case you are running airflow on AWS, you should be able to attach an IAM role to the instance (EC2), tasks (ECS) or pod (EKS) so that credentials are not taken into account but rather the IAM role attached.
Also, AWS has a managed airflow service: https://aws.amazon.com/blogs/aws/introducing-amazon-managed-workflows-for-apache-airflow-mwaa/
QUESTION
I am having a problem with validating the file existence in this script. The script fails when there is not a file in the ADDITION or the DELETIONS path.
How can I validate that there is a file in the ADDITION or DELETION path?
I'm doing my first steps with bash and Makefile so any help will be appreciated.
...ANSWER
Answered 2020-Sep-08 at 15:07you have to make this a huge, single bash command; make executes each line separately in the shell and variables are not available in later steps. To improve readability/maintainability, I would replace the test -f ... && xxx statements here by if blocks.
E.g.
QUESTION
I have the following function from my odd-jobs job-queue library. There are a bunch of configuration parameters where the default implementation depends on another config parameter. For example:
cfgJobToHtmldepends oncfgJobType, which defaults todefaultJobType. However, after callingdefaultConfig, the user may choose to override the value forcfgJobTypewithout changingcfgJobToHtml. The expected behaviour is thatcfgJobToHtmlshould now use the user-provided value instead ofdefaultJobType.- Similarly,
cfgAllJobTypesdepends oncfgJobTypeSql, which in-turn defauls todefaultJobTypeSql. Again, after callingdefaultConfig, if the user overrides the value forcfgJobTypeSql, thencfgAllJobTypesshould use the overridden value, notdefaultJobTypeSql.
The code below does not work the way I'm expecting it to. If you change cfgJobType the change is not picked up by cfgJobToHtml. Similarly, for cfgJobTypeSql.
What is the best way to have these "dependent" default values?
...ANSWER
Answered 2020-May-05 at 15:25People often implement it using builder pattern.
In your example, you first fill the defaults and then let user override some fields if she wants. With builder it's other way around: you let user fill the data she wants to override, then you fill the rest.
Specifically, you make an intermediate data type to hold a partially filled config, ConfigUnderConstruction. All fields there are optional. User can specify all the fields she is interested in, then you assemble the config, filling all the defaults:
QUESTION
I know it probably has something to do with a misconfiguration, but unfortunately the most info I get is
The function runtime is unable to start. Session Id: b939c608ae424150878a55eeac6e7d36 Timestamp: 2018-10-04T18:05:22.023Z
My function looks like
...ANSWER
Answered 2018-Oct-05 at 03:06Without any further info, I assume you may forget to add MyServiceBusConnection in Application settings on Azure portal, which will cause same error you have seen.
If it's not the case, you could go to https://.scm.azurewebsites.net/DebugConsole and navigate to D:\home\LogFiles\Application\Functions\Host to see function runtime logs.
QUESTION
I am writing a cloudformation template for creating an aws step function and statemachine. Following is the part of my template which is causing the error
...ANSWER
Answered 2019-Aug-31 at 11:36AWS cloudformation errors are sometimes quite wierd and its difficult to debug them. But I found the error. It was 9th line JobQueue: arn:aws:batch:${AWS::Region}:${AWS::AccountId}:job-queue/${QueueName and one can easily see that I missed } at the end. So it was a syntax error
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Install job-queue
PHP requires the Visual C runtime (CRT). The Microsoft Visual C++ Redistributable for Visual Studio 2019 is suitable for all these PHP versions, see visualstudio.microsoft.com. You MUST download the x86 CRT for PHP x86 builds and the x64 CRT for PHP x64 builds. The CRT installer supports the /quiet and /norestart command-line switches, so you can also script it.
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