[HBASE-18019] Close redundant memstore scanners

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0
• Fix Version/s: 2.0.0
• Hadoop Flags: Reviewed
• Assignee: Chia-Ping Tsai
• Reporter: Chia-Ping Tsai
• Created: 09/May/17 19:14
• Updated: 01/Jul/22 20:26
• Resolved: 18/May/17 08:08

Description

The HBASE-17655 remove the MemStoreScanner and it causes that the MemStore#getScanner(readpt) returns multi KeyValueScanner which consist of active, snapshot and pipeline. But StoreScanner only remove one mem scanner when refreshing current scanners.

    for (int i = 0; i < currentScanners.size(); i++) {
      if (!currentScanners.get(i).isFileScanner()) {
        currentScanners.remove(i);
        break;
      }
    }

The older scanners kept in the StoreScanner will hinder GC from releasing memory and lead to multiple scans on the same data.

Issue Links

• relates to: HBASE-18145 The flush may cause the corrupt data for reading