package client;
// cc ScanCacheBatchExample Example using caching and batch parameters for scans
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.log4j.Appender;
import org.apache.log4j.AppenderSkeleton;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;
import org.apache.log4j.spi.LoggingEvent;
import util.HBaseHelper;
import java.io.IOException;
public class ScanCacheBatchExample {
private static HTable table = null;
// vv ScanCacheBatchExample
private static void scan(int caching, int batch) throws IOException {
Logger log = Logger.getLogger("org.apache.hadoop");
final int[] counters = {0, 0};
Appender appender = new AppenderSkeleton() {
@Override
protected void append(LoggingEvent event) {
String msg = event.getMessage().toString();
if (msg != null && msg.contains("Call: next")) {
counters[0]++;
}
}
@Override
public void close() {}
@Override
public boolean requiresLayout() {
return false;
}
};
log.removeAllAppenders();
log.setAdditivity(false);
log.addAppender(appender);
log.setLevel(Level.DEBUG);
Scan scan = new Scan();
scan.setCaching(caching); // co ScanCacheBatchExample-1-Set Set caching and batch parameters.
scan.setBatch(batch);
ResultScanner scanner = table.getScanner(scan);
for (Result result : scanner) {
counters[1]++; // co ScanCacheBatchExample-2-Count Count the number of Results available.
}
scanner.close();
System.out.println("Caching: " + caching + ", Batch: " + batch +
", Results: " + counters[1] + ", RPCs: " + counters[0]);
}
public static void main(String[] args) throws IOException {
// ^^ ScanCacheBatchExample
Configuration conf = HBaseConfiguration.create();
HBaseHelper helper = HBaseHelper.getHelper(conf);
helper.dropTable("testtable");
helper.createTable("testtable", "colfam1", "colfam2");
helper.fillTable("testtable", 1, 10, 10, "colfam1", "colfam2");
table = new HTable(conf, "testtable");
// vv ScanCacheBatchExample
scan(1, 1);
scan(200, 1);
scan(2000, 100); // co ScanCacheBatchExample-3-Test Test various combinations.
scan(2, 100);
scan(2, 10);
scan(5, 100);
scan(5, 20);
scan(10, 10);
}
// ^^ ScanCacheBatchExample
}