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HBase, mail # dev - skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner


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skipKVsNewerThanReadpoint in StoreFileScanner and MemStoreScanner
Vladimir Rodionov 2013-10-11, 21:18
>From HRegion:

synchronized(scannerReadPoints) {
        if (isolationLevel == IsolationLevel.READ_UNCOMMITTED) {
          // This scan can read even uncommitted transactions
          this.readPt = Long.MAX_VALUE;
          MultiVersionConsistencyControl.setThreadReadPoint(this.readPt);
        } else {
          this.readPt = MultiVersionConsistencyControl.resetThreadReadPoint(mvcc);
        }

If isolation level is READ_UNCOMMITTED than this method should never be called in both StoreFileScanner and MemStoreScanner
If isolation level is READ_COMMITTED than this method must be called only in MemStoreScanner, because HFiles are immutable no new KV's can be added
to HFile after StoreFileScanner was created.
Correct?
Best regards,
Vladimir Rodionov
Principal Platform Engineer
Carrier IQ, www.carrieriq.com
e-mail: [EMAIL PROTECTED]

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