[
https://issues.apache.org/jira/browse/YARN-5715?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15591602#comment-15591602
]
Varun Saxena commented on YARN-5715:
------------------------------------
Thanks [~rohithsharma] for the patch. Patch looks fine to me.
Few observations.
# Instead of saying "Advantages of setting idPrefix is entities are stored in
natural ascending/descending order." in the javadoc, can we say "Entities will
be stored in the order of id prefix specified". I feel this directly indicates
that prefix id is used for ordering. Thoughts ?
# We should add it in documentation too but as we discussed in another JIRA,
maybe this can be done on YARN-5744. A comment can be left there to update this
part as well so that we dont miss it.
# Regarding Li's comment, we should have a constant like DEFAULT_ENTITY_PREFIX
irrespective of whether it is to be used by clients or not. If it is intended
to be used by clients, we should probably have it inside TimelineEntity.
Checkstyle is related.
> introduce entity prefix for return and sort order
> -------------------------------------------------
>
> Key: YARN-5715
> URL: https://issues.apache.org/jira/browse/YARN-5715
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: timelineserver
> Reporter: Sangjin Lee
> Assignee: Rohith Sharma K S
> Priority: Critical
> Attachments: YARN-5715-YARN-5355.01.patch,
> YARN-5715-YARN-5355.02.patch, YARN-5715-YARN-5355.03.patch,
> YARN-5715-YARN-5355.04.patch
>
>
> While looking into YARN-5585, we have come across the need to provide a sort
> order different than the current entity id order. The current entity id order
> returns entities strictly in the lexicographical order, and as such it
> returns the earliest entities first. This may not be the most natural return
> order. A more natural return/sort order would be from the most recent
> entities.
> To solve this, we would like to add what we call the "entity prefix" in the
> row key for the entity table. It is a number (long) that can be easily
> provided by the client on write. In the row key, it would be added before the
> entity id itself.
> The entity prefix would be considered mandatory. On all writes (including
> updates) the correct entity prefix should be set by the client so that the
> correct row key is used. The entity prefix needs to be unique only within the
> scope of the application and the entity type.
> For queries that return a list of entities, the prefix values will be
> returned along with the entity id's. Queries that specify the prefix and the
> id should be returned quickly using the row key. If the query omits the
> prefix but specifies the id (query by id), the query may be less efficient.
> This JIRA should add the entity prefix to the entity API and add its handling
> to the schema and the write path. The read path will be addressed in
> YARN-5585.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
