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https://issues.apache.org/jira/browse/HDDS-3354?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17093754#comment-17093754
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Bharat Viswanadham commented on HDDS-3354:
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Hi [~elek]
Thanks for reviewing design doc.
{quote}What is the performance impact of turning on sync of write. It seems
that we make the restart faster but making the production run slower. Is it
true? Do you have numbers of the additional cost of the sync write?{quote}
We don't sync to be turned on. As rockdb batch put is an atomic operation.
After a OM restart, we can read transaction information from the table, and use
this as last applied Index.
To add more info, even sync write also does not impact write request
performance, as this is running in background thread, and write does not wait
for the flush to be completed. But now any way for HA, we don't need sync to be
turned on.
{quote}It's not clear the structure of the new table. You wrote "For this, we
can have a new table in rocks db with key as timestamp and value as largest
transaction index in that batch flush to DB." But you mentioned a String->long
table. And in the document you mentioned that only one key will be used. What
will be the content of the table?{quote}
During implementation figured that we need both term and log index. So modified
it during the implementation.
Table -> ratislogTable.
Key = TRANSACTIONINFO
value = currentTerm-transactionIndex
I will update the doc also, as during implementation figured few more things.
> OM HA replay optimization
> -------------------------
>
> Key: HDDS-3354
> URL: https://issues.apache.org/jira/browse/HDDS-3354
> Project: Hadoop Distributed Data Store
> Issue Type: Improvement
> Reporter: Bharat Viswanadham
> Assignee: Bharat Viswanadham
> Priority: Major
> Attachments: OM HA Replay.pdf
>
>
> This Jira is to improve the OM HA replay scenario.
> Attached the design document which discusses about the proposal and issue in
> detail.
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