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https://issues.apache.org/jira/browse/PHOENIX-3744?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16023273#comment-16023273
]
ASF GitHub Bot commented on PHOENIX-3744:
-----------------------------------------
Github user JamesRTaylor commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/239#discussion_r118313746
--- Diff:
phoenix-core/src/main/java/org/apache/phoenix/mapreduce/PhoenixInputFormat.java
---
@@ -185,7 +184,7 @@ private QueryPlan getQueryPlan(final JobContext
context, final Configuration con
scan.setAttribute(BaseScannerRegionObserver.TX_SCN,
Bytes.toBytes(Long.valueOf(txnScnValue)));
}
// Initialize the query plan so it sets up the parallel scans
- queryPlan.iterator(MapReduceParallelScanGrouper.getInstance());
+
queryPlan.iterator(TableMRParallelScanGrouper.init(configuration));
--- End diff --
Can't this just instantiate a TableMRParallelScanGrouper and the init
method can be invoked in the constructor so that it doesn't need to be exposed
in the interface?
> 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
>
>
> 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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