logback dbappender very slow - performance

Question

I have a custom DB Appender which extends the logback DBAppender. My application has 100 parallel threads. These threads also log the events into database through the custom db appender while processing the requests.
The performance of the logback is so slow that with the logs disabled, the execution finishes in 20 mins. Whereas with the logs enabled, it takes almost 5 hours to finish most of the time waiting for the logs to be written to proceed to the next step as my logging is synchronous.
At first I thought the slow performance could be due to the synchronized doAppend method of logback appender. However, I later noticed that DB appender extends the
UnsynchronizedAppenderBase(public abstract class DBAppenderBase<E>
/* */ extends UnsynchronizedAppenderBase<E>).
Can anyone help me understand what could be the reason for this poor performance?
My DB Appender:
package com.test;
import java.io.StringReader;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map;
import org.omg.CORBA.TRANSACTION_UNAVAILABLE;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import ch.qos.logback.classic.db.DBAppender;
import ch.qos.logback.classic.spi.ILoggingEvent;
public class CustomDBAppender extends DBAppender {
final static Logger logger = LoggerFactory.getLogger("com.test");
protected String insertPropertiesSQL;
protected String insertExceptionSQL;
protected String insertSQL;
private CustomDBNameResolver dbNameResolver;
// default constructor
public CustomDBAppender() {
logger.debug("DB Appender instantiated");
}
// set dbNameResolver for getting table information
public void setCsiDbNameResolver(CustomDBNameResolver dbNameResolver) {
this.dbNameResolver = dbNameResolver;
}
#Override
public void start() {
super.start();
if (dbNameResolver == null)
dbNameResolver = new CustomDBNameResolver();
insertSQL = CustomSQLBuilder.buildInsertSQL(dbNameResolver);
}
#Override
protected void subAppend(ILoggingEvent event, Connection connection, PreparedStatement insertStatement)
throws Throwable {
logEvents(insertStatement, event);
// System.out.println("=== INSERT STATEMENT === " +
// insertStatement.toString());
int updateCount = -1;
try {
updateCount = insertStatement.executeUpdate();
} catch (Exception e) {
logger.error(" ERROR ");
e.printStackTrace();
}
logger.info(" updateCount = " + updateCount);
if (updateCount != 1) {
logger.error(" ERROR IT IS ");
addWarn("Failed to insert loggingEvent");
}
}
protected void secondarySubAppend(ILoggingEvent event, Connection connection, long eventId) throws Throwable {
}
// #override
private void logEvents(PreparedStatement stmt, ILoggingEvent event) throws SQLException {
logData(event, stmt);
}
private void logData(ILoggingEvent event, PreparedStatement stmt) throws SQLException {
try {
if (null != event && null != logMsgArgs && (event.getLoggerName().indexOf("com.test.beans.") != -1)) {
payload = null == logMsgArgs[0] ? "NA"
: (logMsgArgs[0].toString()).substring(0,
(logMsgArgs[0].toString().length() >= 4000 ? 3999 : logMsgArgs[0].toString().length()));
msgHeader = null == logMsgArgs[1] ? "NA"
: (logMsgArgs[1].toString()).substring(0,
(logMsgArgs[1].toString().length() >= 4000 ? 3999 : logMsgArgs[1].toString().length()));
currentStage = null == logMsgArgs[2] ? -1 : Integer.parseInt(logMsgArgs[2].toString());
currentEvent = null == logMsgArgs[3] ? null : logMsgArgs[3].toString();
trxId = null == logMsgArgs[4] ? null : logMsgArgs[4].toString();
batchId = null == logMsgArgs[5] ? null : logMsgArgs[5].toString();
headerId = null == logMsgArgs[6] ? null : logMsgArgs[6].toString();
}
stmt.setString(1, logLevel);
stmt.setObject(2, trxId);
stmt.setString(3, logMessage);
stmt.setDate(4, getSqlDate());
stmt.setString(5, event.getLoggerName());
stmt.setString(6, event.getThreadName());
stmt.setString(7, event.getLoggerContextVO().getName());
stmt.setString(8, logMessage.substring(0, logMessageLength));
stmt.setString(9, payload);
stmt.setString(10, msgHeader);
stmt.setInt(11, currentStage);
stmt.setString(12, currentEvent);
stmt.setString(13, batchId);
stmt.setString(14, headerId);
} catch (Exception e) {
// TODO Auto-generated catch block
System.out.println("Exception while printing log:" + e.getMessage());
e.printStackTrace();
} finally {
}
}
private Object nvl(Object input) {
if (null == input) {
return null;
}
return input;
}
private java.sql.Date getSqlDate() {
Date now = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSSX");
String nowDateStr = sdf.format(now);
logger.info("nowDateStr = " + nowDateStr);
java.sql.Date toDB = null;
try {
toDB = new java.sql.Date(sdf.parse(nowDateStr).getTime());
logger.info("toDB = " + toDB);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return toDB;
}
#Override
protected String getInsertSQL() {
return insertSQL;
}
protected void insertProperties(Map<String, String> mergedMap, Connection connection, long eventId)
throws SQLException {
}
}
/* End of appender */