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https://issues.apache.org/jira/browse/TEPHRA-99?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16167543#comment-16167543
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Micael Capitão commented on TEPHRA-99:
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Well the thing here is: when the client first requests a page I'm opening a new
scan, fetch records until a certain limit and then return the records plus the
last row and the tx (the scan is closed). On the next pages the client provides
me the last row and the tx info and I repeat the procedure but starting the
scan at the last row (excluded) and injecting the tx info from the first page
(that is the part that I'm going to do now).
The truth is I don't really want to start a transaction on the pages after the
first one (and on the first page I do have to start a transaction and commit
it). I only need the transaction info to go with the scan so the Thephra
coprocessor can do its job at filtering anything that should not be seen by the
tx I've injected. So in reality there should be no issues at all or am I
missing something here?
> Make "long running" transactions usable with TransactionContext
> ---------------------------------------------------------------
>
> Key: TEPHRA-99
> URL: https://issues.apache.org/jira/browse/TEPHRA-99
> Project: Tephra
> Issue Type: Improvement
> Components: core
> Reporter: Gary Helmling
> Assignee: Gary Helmling
>
> "Long running" transactions (type == LONG) are supported by the Tephra
> {{TransactionManager}}, but {{TransactionContext}} does not expose any way
> for clients to interact with them. I think this will require a couple
> changes:
> * add a {{startLong()}} method to TransactionContext
> * add a constructor to TransactionContext that takes an existing
> {{Transaction}} instance. Since long running transactions are often used in
> map reduce processing, the process committing the transaction may be
> different from the process that started the transaction. In this situation,
> we need a way to pass the serialized transaction all the way through to the
> other process.
> Regarding map reduce support, we could use additional utilities or support in
> place to make transactions easier to use with map reduce. But this would at
> least serve as a first step.
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