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POHbase read performance varying abnormally
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copied!<p>I've installed HBase 0.94.0. I had to improve my read performance through scan. I've inserted random 100000 records.</p> <p>When I set <code>setCache(100);</code> my performance was 16 secs for 100000 records.</p> <p>When I set it to <code>setCache(50)</code> my performance was 90 secs for 100000 records.</p> <p>When I set it to <code>setCache(10);</code> my performance was 16 secs for 100000 records</p> <pre><code>public class Test { public static void main(String[] args) { long start, middle, end; HTableDescriptor descriptor = new HTableDescriptor("Student7"); descriptor.addFamily(new HColumnDescriptor("No")); descriptor.addFamily(new HColumnDescriptor("Subject")); try { HBaseConfiguration config = new HBaseConfiguration(); HBaseAdmin admin = new HBaseAdmin(config); admin.createTable(descriptor); HTable table = new HTable(config, "Student7"); System.out.println("Table created !"); start = System.currentTimeMillis(); for(int i =1;i<100000;i++) { String s=Integer.toString(i); Put p = new Put(Bytes.toBytes(s)); p.add(Bytes.toBytes("No"), Bytes.toBytes("IDCARD"),Bytes.toBytes("i+10")); p.add(Bytes.toBytes("No"), Bytes.toBytes("PHONE"),Bytes.toBytes("i+20")); p.add(Bytes.toBytes("No"), Bytes.toBytes("PAN"),Bytes.toBytes("i+30")); p.add(Bytes.toBytes("No"), Bytes.toBytes("ACCT"),Bytes.toBytes("i+40")); p.add(Bytes.toBytes("Subject"), Bytes.toBytes("English"),Bytes.toBytes("50")); p.add(Bytes.toBytes("Subject"), Bytes.toBytes("Science"),Bytes.toBytes("60")); p.add(Bytes.toBytes("Subject"), Bytes.toBytes("History"),Bytes.toBytes("70")); table.put(p); } middle = System.currentTimeMillis(); Scan s = new Scan(); s.setCaching(100); ResultScanner scanner = table.getScanner(s); try { for (Result rr = scanner.next(); rr != null; rr=scanner.next()) { System.out.println("Found row: " + rr); } end = System.currentTimeMillis(); } finally { scanner.close(); } System.out.println("TableCreation-Time: " + (middle - start)); System.out.println("Scan-Time: " + (middle - end)); } catch (IOException e) { System.out.println("IOError: cannot create Table."); e.printStackTrace(); } } } </code></pre> <p>Why is this happening? </p>

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