Here is my bench for large table scan if you want to try. Tell me if
you spot a mistake.
package org.h2.test.bench;
import java.sql.PreparedStatement;
import java.sql.SQLException;
/**
* Test the table scan performance for a table that fit in memory.
* Test also aggregation as it return the sum.
*/
public class BenchScanLarge implements Bench {
private Database db;
private int size;
/**
* Use a number not so small in order
* to not fit in memory
*/
public static int NUMBER_OF_FACTS = 10*1000*1000;
public void init(Database db, int size) throws SQLException {
this.db = db;
this.size = Math.max(1, size/1000);
db.start(this, "Init");
db.openConnection();
try{
db.update("CREATE TABLE FACTS_LARGE(ID INT NOT NULL
PRIMARY KEY,
FACT1 DECIMAL(15,2), FACT2 DECIMAL(15,2))");
PreparedStatement prep;
db.setAutoCommit(false);
int commitEvery = 1000;
prep = db.prepare("INSERT INTO
FACTS_LARGE(ID,FACT1,FACT2) VALUES
(?,?,?)");
for (int i = 0; i < NUMBER_OF_FACTS; i++) {
prep.setInt(1, i);
prep.setDouble(2, i);
prep.setDouble(3, i);
db.update(prep, "insertFacts");
if (i % commitEvery == 0) {
db.commit();
}
}
db.commit();
} catch(Exception e) {
// nothing to do, the table already exists, it's cool.
}
db.commit();
db.closeConnection();
db.end();
}
public void runTest() throws SQLException {
db.start(this, "Scanning");
db.openConnection();
processQuery();
db.closeConnection();
db.end();
db.openConnection();
processQuery();
db.logMemory(this, "Memory Usage");
db.closeConnection();
}
private void processQuery() throws SQLException {
PreparedStatement scan1 = db.prepare("SELECT SUM(FACT1) FROM
FACTS_LARGE");
db.setAutoCommit(false);
for (int i = 0; i < size; i++) {
db.queryReadResult(scan1);
db.commit();
}
scan1.close();
}
public String getName() {
return "ScanLarge";
}
}
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