Compatibility with segment replication

[dreamer-89]

Coming from #936 (comment) and with core now supporting real time reads for segment replication enabled indices (opensearch-project/OpenSearch#8536), we can revert #948 which enforces DOCUMENT replication strategy.

CC @kaituo @ohltyler

Request owners to label this issue with 2.10.0 release.

[kaituo]

will respond later.

[jackiehanyang]

revert change pr created - #999

@dreamer-89 do you have any instruction on how to test this to ensure the core side change is working well with AD?

[dreamer-89]

revert change pr created - #999

@dreamer-89 do you have any instruction on how to test this to ensure the core side change is working well with AD?

Thanks @jackiehanyang for working on this change. I commented on revert PR #999

[kaituo]

I've conducted a comprehensive review of our backend and would like to share my insights on two key components:

1. State Index Query:

• The real-time performance is satisfactory, especially since it primarily supports the profile API. The RAW feature is not required.
• For historical detectors, a change may or may not be necessary. Interestingly, ml-commons has no reported issues and historical detectors have implementation similar to ml-commons. You can refer to Issue #1023 which Yaliang has reviewed and signed off on. Should any modifications be required, TaskManager.getAndExecuteOnLatestTasks should prioritize primary shards to locate the most recent task.

2. Result Index Query from Alerting:

As indicated in Issue #974, there's a slight delay of a few seconds. However, given that we operate with a minute-level delay, I believe this won't pose any significant concerns.

In light of the above, I am inclined to approve Pull Request #999 . This should allow us to finalize the seg replication compatibility.

[dreamer-89]

Thanks @kaituo for the summary and explanation. Do we need anything else other than merging PR #999 ? If not, do you mind merging #999 and closing this issue.

[kaituo]

We do need another approver.

[dreamer-89]

@kaituo @jackiehanyang : As PR #999 is merged and backported. Do you mind closing this issue if nothing else is pending.

[dreamer-89]

@kaituo @owaiskazi19 @jackiehanyang : Mind closing this issue if nothing else is pending