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

["James Taylor (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/PHOENIX-3744?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16035636#comment-16035636 ] 

James Taylor edited comment on PHOENIX-3744 at 6/2/17 11:52 PM:
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Would you mind attaching a patch that applies to 4.x-HBase-0.98 branch, [~akshita.malhotra]?

Also, for 4.x-HBase-1.1 branch, I get the following compilation error. Would you mind attaching a patch that'll work for that branch?
{code}
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.0:compile (default-compile) on project phoenix-core: Compilation failure: Compilation failure:
[ERROR] /home/jtaylor/dev/apache/phoenix/phoenix-core/src/main/java/org/apache/phoenix/iterate/TableSnapshotResultIterator.java:[60,53] incompatible types
[ERROR] required: org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper.RestoreMetaChanges
[ERROR] found:    void
[ERROR] /home/jtaylor/dev/apache/phoenix/phoenix-core/src/main/java/org/apache/phoenix/iterate/TableSnapshotResultIterator.java:[63,20] cannot find symbol
[ERROR] symbol:   method getTableDescriptor()
[ERROR] location: variable meta of type org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper.RestoreMetaChanges
[ERROR] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException
[ERROR] 
[ERROR] After correcting the problems, you can resume the build with the command
[ERROR]   mvn <goals> -rf :phoenix-core
{code}

FYI, looks fine on master and 4.x-HBase-1.2 branches, so I've committed it there.


was (Author: jamestaylor):
Would you mind attaching a patch that applies to 4.x-HBase-0.98 branch, [~akshita.malhotra]?

> 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.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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