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https://issues.apache.org/jira/browse/IGNITE-27019?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Daria Usova reassigned IGNITE-27019:
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Assignee: Daria Usova
> Update documentation for Partition API usage in Compute Jobs
> ------------------------------------------------------------
>
> Key: IGNITE-27019
> URL: https://issues.apache.org/jira/browse/IGNITE-27019
> Project: Ignite
> Issue Type: Improvement
> Components: documentation ai3
> Affects Versions: 3.1
> Reporter: Tiago Marques Godinho
> Assignee: Daria Usova
> Priority: Major
> Labels: ignite-3
>
> The documentation must be made more clear regarding usages of Partitions
> inside compute jobs, specially when broadcasted to table partitions.
> What to do:
> # Make sure we have examples for TableBroadcast Job targets. Using
> jobContext.partition() and passing it to SQL inside the job.
> # MapReduce that works with table partitions.
> # Add a section to the migration guide about collocated computes and
> partition and local node queries. The documentation must clearly answer:
> ** How can I do `setPartition` in ignite 3 ?
> *** Show an example of a Map/Reduce job or a compute job (with TableBroadcast
> Job targets) fetching the context.partition() and injecting in it a SQL Query
> using the `__PARTITION_ID` column.
> ** How can I do a local query ?
> *** The user should prefer Map/Reduce or compute jobs (with TableBroadcast
> Job targets) to guarantee local execution of queries.
> *** Alternatively, the user can manually select local partitions using the
> Partition Distribution API, however, this performs in a best-effort basis
> since reassignments can happen concurrently. Nonetheless, might be good for
> debugging/prototyping (not production code).
> Notes:
> Example 1:
> {code:java}
> // Map/Reduce style example (TableJobTarget)
> submitAsync(BroadcastJobTarget.table(QualifiedName.of(null, "foo")),
> jobDescriptor,args)
> // Compute job implementation
> CompletableFuture<R> executeAsync(JobExecutionContext context, @Nullable T
> arg) {
> Partition part = context.partition();
> ignite.sql().execute("SELECT * FROM foo WHERE foo.__PARTITION_ID = ?",
> part.id());
> ...
> }
> {code}
> Example 2:
> Similar to example 1 but using the MapReduce API.
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