If you can make your hobby your profession, you never have to work another day in your life. —Anonymous

Sure, here’s a suggested outline for a deep dive technical blog post in Markdown format to help solve problems related to lock wait timeout exceptions and data persistence issues:

Troubleshooting Lock Wait Timeout Exceptions and Data Persistence Issues

Introduction

In this blog post, we’ll provide a comprehensive guide for troubleshooting lock wait timeout exceptions and data persistence issues. These problems can significantly impact application performance and data integrity, making it crucial to understand their root causes and effective troubleshooting techniques.

Enabling Detailed Logging

Detailed logging is essential for troubleshooting issues in your application. Here’s how you can enable detailed logging in Spring, Hibernate, and MySQL:

Spring and Hibernate

logging:
  level:
    ROOT: INFO
    org:
      springframework:
        jdbc: TRACE
      hibernate: TRACE

MySQL

datasource:
  master:
    platform: mysql
    driverClass: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mydb?useUnicode=true&characterEncoding=UTF-8&useUnicode=true&serverTimezone=Asia/Hong_Kong&useLegacyDatetimeCode=false&logger=com.mysql.cj.log.StandardLogger&profileSQL=true
    jdbcUrl: jdbc:mysql://localhost:3306/mydb?useUnicode=true&characterEncoding=UTF-8&useUnicode=true&serverTimezone=Asia/Hong_Kong&useLegacyDatetimeCode=false&logger=com.mysql.cj.log.StandardLogger&profileSQL=true

Commit Operations in JPA

Understanding the commit process in JPA and Spring’s TransactionAspectSupport class is crucial for troubleshooting data persistence issues. Here’s an example of the commitTransactionAfterReturning method:

protected void commitTransactionAfterReturning(@Nullable TransactionInfo txInfo) {
    if (txInfo != null && txInfo.getTransactionStatus() != null) {
        if (logger.isTraceEnabled()) {
            logger.trace("Completing transaction for [" + txInfo.getJoinpointIdentification() + "]");
        }
        txInfo.getTransactionManager().commit(txInfo.getTransactionStatus());
    }
}

Testing with autoCommit = false

When autoCommit is set to false, your application may exhibit different behavior. Here’s an example log excerpt and code snippet illustrating this scenario:

Thu May 16 20:21:08 AEST 2024 INFO: [QUERY] rollback [Created on: Thu May 16 20:21:08 AEST 2024, duration: 1, connection-id: 2225, statement-id: -1, resultset-id: 0,   at com.zaxxer.hikari.pool.ProxyConnection.close(ProxyConnection.java:257)]

{
    if (isCommitStateDirty && !isAutoCommit) {
        delegate.rollback();

Local Debugging

Local debugging is a powerful tool for troubleshooting issues in your application. Here’s an example log excerpt from a local debugging session:

2024-05-16 18:52:43.626 [] [UnfiyXPScheduler_Worker-14] DEBUG c.zaxxer.hikari.pool.ProxyConnection - HikariPool-2 - Executed rollback on connection com.mysql.cj.jdbc.ConnectionImpl@59282dc6 due to dirty commit state on close().

Customization and Data Persistence

In some cases, customization data may not persist correctly. Here’s an example log excerpt and code snippet related to this issue:

2024-05-16 19:18:30.013 [] [http-nio-8080-exec-1] DEBUG o.s.jdbc.core.JdbcTemplate - Executing prepared SQL statement [INSERT INTO UserCart (`uuid`, `storeUuid`, `salesChannelUuid`, `shoppingCartUuid`, `salesChannelProductUuid`, `productUuid`, `salePrice`, `amount`, `currencyCode`, `discountPrice`, `totalPrice`, `discountUuids`, `seq`, `customisation`, `checked`, `deleted`, `valid`, `createdBy`, `modifiedBy`, `type`, `discountCodes`, `discountDetails`, `flashSale`, `subscribed`, `subscription`, `subscriptionBuyUuid`, `subscriptionBuyDiscount`, `totalTax`, `voucherUuids`, `discountUuid`, `parentUuid`, `flashSaleUuid`, `flashSaleDiscount`, `orderLineItemUuid`, `flashSaleEndTime`, `originalPrice`, `voucherDiscount`, `deletedStatus`, `customisationSplit`) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?) ON DUPLICATE KEY UPDATE `shoppingCartUuid` = ?, `salesChannelProductUuid` = ?, `productUuid` = ?, `salePrice` = ?, `amount` = ?, `currencyCode` = ?, `discountPrice` = ?, `totalPrice` = ?, `discountUuids` = ?, `seq` = ?, `customisation` = ?, `checked` = ?, `deleted` = ?, `valid` = ?, `modifiedBy` = ?, `type` = ?, `discountCodes` = ?, `discountDetails` = ?, `flashSale` = ?, `subscribed` = ?, `subscription` = ?, `subscriptionBuyUuid` = ?, `subscriptionBuyDiscount` = ?, `totalTax` = ?, `voucherUuids` = ?, `discountUuid` = ?, `parentUuid` = ?, `flashSaleUuid` = ?, `flashSaleDiscount` = ?, `orderLineItemUuid` = ?, `flashSaleEndTime` = ?, `originalPrice` = ?, `voucherDiscount` = ?, `deletedStatus` = ?, `customisationSplit` = ?, `modifiedDate` = now() ;]

size = 39
customisation is null
// ...
setNull:253, StatementCreatorUtils (org.springframework.jdbc.core)

Transaction Management and Commit Process

Understanding the transaction management process in Spring and Hibernate is crucial for troubleshooting data persistence issues. Here are some relevant code snippets and explanations:

// TransactionAspectSupport
protected Object invokeWithinTransaction(...)
    -> commitTransactionAfterReturning(txInfo);

// JpaTransactionManager
doCommit(...)
    -> jdbcResourceTransaction.commit()

// JdbcResourceLocalTransactionCoordinatorImpl
commit()
    // Commit the JDBC resource

Connection Management and Rollback

Connection management and the conditions under which a rollback occurs are also important factors to consider. Here’s an example code snippet from the ProxyConnection class in the HikariCP library:

if (isCommitStateDirty && !isAutoCommit) {
    delegate.rollback();
    lastAccess = currentTime();
    LOGGER.debug("{} - Executed rollback on connection {} due to dirty commit state on close().", poolEntry.getPoolName(), delegate);
}

Conclusion

In this blog post, we’ve covered several aspects of troubleshooting lock wait timeout exceptions and data persistence issues, including enabling detailed logging, understanding commit operations in JPA, testing with autoCommit = false, local debugging, customization and data persistence, transaction management and commit processes, and connection management and rollback.

By following the best practices for transaction management, connection handling, and logging, you can prevent and effectively troubleshoot similar issues in your application. Remember to always review your application’s logs and code carefully, as they can provide valuable insights into the root cause of the problem.

–HTH–

Updated:

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