The problem is that the database is growing much more than it should
(as if there was an uncommitted, long-running transaction - but there
isn't any). This is accompanied by "pageStore: Transaction log could
not be truncated" warning in *.trace.db. The problem disappears if I
manually force CHECKPOINT after every commit. As far as I know (I read
it some time ago in one of your posts:
https://groups.google.com/group/h2-database/browse_thread/thread/b26bbac61cc2a185)
manual checkpointing should not be neccessary.
I simplified the testcase. Please find it attached below:
package H2_Growing_txn_log_issue;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.Statement;
import java.util.Random;
import org.h2.jdbcx.JdbcDataSource;
public class H2_Growing_txn_log_issue
{
private static final String DATA_TABLE_NAME = "MATDB_DATA";
public static void main(String[] args) throws Exception
{
// create/open the DB
System.setProperty("h2.lobInDatabase", "true");
String dbUrl = "jdbc:h2:split:" +
System.getProperty("java.io.tmpdir") + "txn_log_issue";
JdbcDataSource ds = new JdbcDataSource();
ds.setURL(dbUrl);
Connection dbConn = ds.getConnection();
// create data table and a relevant precompiled insertion
statement
Statement st = null;
st = dbConn.createStatement();
st.executeUpdate("CREATE TABLE IF NOT EXISTS " +
DATA_TABLE_NAME + "(DATA BLOB)");
st.close();
PreparedStatement tableDataInsertSt =
dbConn.prepareStatement("INSERT INTO " + DATA_TABLE_NAME + "
VALUES(?)");
// do the test
Random random = new Random(0xBAD); // ensure full
repeatability
for (int i = 0; i < 1024; ++i) {
// start a transaction
dbConn.setAutoCommit(false);
// generate some data
byte[] data = new byte[(int)(random.nextDouble() *
102400)];
random.nextBytes(data);
// save the data in the DB
tableDataInsertSt.setBytes(1, data);
tableDataInsertSt.executeUpdate();
tableDataInsertSt.clearParameters();
// commit the transaction
dbConn.commit();
//st.executeUpdate("CHECKPOINT"); // if uncommented this
prevents the transaction log from growing
}
tableDataInsertSt.close();
// done
dbConn.close();
}
}
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