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https://issues.apache.org/jira/browse/HBASE-18059?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16013103#comment-16013103
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Appy commented on HBASE-18059:
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yes sir. It was a part of HBASE-15236.
bq. But in CompactingMemStore and DefaultMemStore, the scanner order for
memstore scanner is also start from 0, which will be messed up with
StoreFileScanners.
Yes, if memstorescanners start from 0, it'll be bug.
But i see following in CompactingMemStore,
{noformat}
long order = 1 + pipelineList.size() + snapshotList.size();
{noformat}
Didn't dig around enough to make sure if it'll ensure that lowest number
assigned to memstore is more than number of store files.
> The scanner order for memstore scanners are wrong
> -------------------------------------------------
>
> Key: HBASE-18059
> URL: https://issues.apache.org/jira/browse/HBASE-18059
> Project: HBase
> Issue Type: Bug
> Components: regionserver, scan, Scanners
> Affects Versions: 2.0.0
> Reporter: Duo Zhang
> Fix For: 2.0.0
>
>
> This is comments for KeyValueScanner.getScannerOrder
> {code:title=KeyValueScanner.java}
> /**
> * Get the order of this KeyValueScanner. This is only relevant for
> StoreFileScanners and
> * MemStoreScanners (other scanners simply return 0). This is required for
> comparing multiple
> * files to find out which one has the latest data. StoreFileScanners are
> ordered from 0
> * (oldest) to newest in increasing order. MemStoreScanner gets LONG.max
> since it always
> * contains freshest data.
> */
> long getScannerOrder();
> {code}
> As now we may have multiple memstore scanners, I think the right way to
> select scanner order for memstore scanner is to ordered from Long.MAX_VALUE
> in decreasing order.
> But in CompactingMemStore and DefaultMemStore, the scanner order for memstore
> scanner is also start from 0, which will be messed up with StoreFileScanners.
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