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https://issues.apache.org/jira/browse/CAMEL-11223?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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TEIKITEETINI-VAYSSE Loic updated CAMEL-11223:
---------------------------------------------
Description:
Deploying 4 instances of the same app containing a camel-jpa consumer polling
on the same database, I noticed that several servers can consume the same
entities.
The polling is currently done as follow :
# Poll without lock on the `maxResult` first rows
# On each row :
## Apply a lock _select ... for update (NOWAIT)_
## Consume entity
## Release the lock (commit)
## New Transaction
## Process exchange
## End Transaction
What can happen with several instances of the consuming on the same database is
:
# {color:green}Server 1 polls the 10 first rows{color}
# {color:red}Server 2 polls the same 10 first rows{color}
# {color:green}Server 1 locks row 1 for update and consume it{color}
# {color:red}Server 2 locks row 1 for update as the previous lock is already
released and consumes it{color}
This demand is related to my previous post on the user forum :
http://camel.465427.n5.nabble.com/JPA-consumer-component-is-not-handling-multiple-server-concurrent-polling-td5797937.html
was:
Deploying 4 instances of the same app containing a camel-jpa consumer polling
on the same database, I noticed that several servers can consume the same
entities.
The polling is currently done as follow :
# Poll without lock on the `maxResult` first rows
# On each row :
## Apply a lock _select ... for update (NOWAIT)_
## Consume entity
## Release the lock (commit)
What can happen with several instances of the consuming on the same database is
:
# {color:green}Server 1 polls the 10 first rows{color}
# {color:red}Server 2 polls the same 10 first rows{color}
# {color:green}Server 1 locks row 1 for update and consume it{color}
# {color:red}Server 2 locks row 1 for update as the previous lock is already
released and consumes it{color}
One fix could be to add a _@IsConsumed_ annotation defining a method to check
whether or not the entity has already been consumed. This method would be
called at the beginning of the _batchProcess_. That is the work around we
applied on our project but directly in our route ie without modifying the
component.
This demand is related to my previous post on the user forum :
http://camel.465427.n5.nabble.com/JPA-consumer-component-is-not-handling-multiple-server-concurrent-polling-td5797937.html
> camel-jpa doesn't handle exclusive locks for concurrent consumers when
> setting consumeDelete to false
> -----------------------------------------------------------------------------------------------------
>
> Key: CAMEL-11223
> URL: https://issues.apache.org/jira/browse/CAMEL-11223
> Project: Camel
> Issue Type: Improvement
> Components: camel-jpa
> Affects Versions: 2.18.3
> Environment: Java JDK 1.8.0_121
> Spring 4 (reproduced with Spring Boot 1.5.3)
> RedHat RHEL 7.1 x86_64
> Oracle 11G
> Reporter: TEIKITEETINI-VAYSSE Loic
>
> Deploying 4 instances of the same app containing a camel-jpa consumer polling
> on the same database, I noticed that several servers can consume the same
> entities.
> The polling is currently done as follow :
> # Poll without lock on the `maxResult` first rows
> # On each row :
> ## Apply a lock _select ... for update (NOWAIT)_
> ## Consume entity
> ## Release the lock (commit)
> ## New Transaction
> ## Process exchange
> ## End Transaction
> What can happen with several instances of the consuming on the same database
> is :
> # {color:green}Server 1 polls the 10 first rows{color}
> # {color:red}Server 2 polls the same 10 first rows{color}
> # {color:green}Server 1 locks row 1 for update and consume it{color}
> # {color:red}Server 2 locks row 1 for update as the previous lock is already
> released and consumes it{color}
> This demand is related to my previous post on the user forum :
> http://camel.465427.n5.nabble.com/JPA-consumer-component-is-not-handling-multiple-server-concurrent-polling-td5797937.html
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