Duo Zhang created HBASE-18059:
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Summary: 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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