[jira] [Updated] (PHOENIX-3744) Support snapshot scanners for MR-based queries

["Akshita Malhotra (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PHOENIX-3744?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Akshita Malhotra updated PHOENIX-3744:
--------------------------------------
    Attachment: PHOENIX-3744-4.x-HBase-0.98.patch

> Support snapshot scanners for MR-based queries
> ----------------------------------------------
>
>                 Key: PHOENIX-3744
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-3744
>             Project: Phoenix
>          Issue Type: Bug
>            Reporter: James Taylor
>            Assignee: Akshita Malhotra
>         Attachments: PHOENIX-3744-4.x-HBase-0.98.patch, PHOENIX-3744.patch, PHOENIX-3744.patch, PHOENIX-3744.patch
>
>
> HBase support scanning over snapshots, with a SnapshotScanner that accesses the region directly in HDFS. We should make sure that Phoenix can support that.
> Not sure how we'd want to decide when to run a query over a snapshot. Some ideas:
> - if there's an SCN set (i.e. the query is running at a point in time in the past)
> - if the memstore is empty
> - if the query is being run at a timestamp earlier than any memstore data
> - as a config option on the table
> - as a query hint
> - based on some kind of optimizer rule (i.e. based on estimated # of bytes that will be scanned)
> Phoenix typically runs a query at the timestamp at which it was compiled. Any data committed after this time should not be seen while a query is running.



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