bitsCN.com
MySQL死锁导致无法查询解决
最近在维护数据库时,解析数据时候,数据一直不能入库。原因知道,是因为MySQL的事务产生了死锁,前几次我直接重启MySQL。
最近发现频繁的出现。所以找到一种方法。
SELECT * FROM INFORMATION_SCHEMA.INNODB_TRX;
trx_id trx_state trx_started trx_requested_lock_id trx_wait_started trx_weight trx_mysql_thread_id trx_query trx_operation_state trx_tables_in_use trx_tables_locked trx_lock_structs trx_lock_memory_bytes trx_rows_locked trx_rows_modified trx_concurrency_tickets trx_isolation_level trx_unique_checks trx_foreign_key_checks trx_last_foreign_key_error trx_adaptive_hash_latched trx_adaptive_hash_timeouttrx_id trx_state trx_started trx_requested_lock_id trx_wait_started trx_weight trx_mysql_thread_id trx_query trx_operation_state trx_tables_in_use trx_tables_locked trx_lock_structs trx_lock_memory_bytes trx_rows_locked trx_rows_modified trx_concurrency_tickets trx_isolation_level trx_unique_checks trx_foreign_key_checks trx_last_foreign_key_error trx_adaptive_hash_latched trx_adaptive_hash_timeout
查看事件比较久的事物。如何当前时间select sysdate();AM 10:07而事物开始的时间是:AM 9:50,显示是不正常的。根据这个事物的线程ID(trx_mysql_thread_id)。
执行命令:
kill 线程ID
数据库修复正常。
查看正在锁的事务
SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCKS;
查看等待锁的事务
SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCK_WAITS;
bitsCN.com

MySQL processes data replication through three modes: asynchronous, semi-synchronous and group replication. 1) Asynchronous replication performance is high but data may be lost. 2) Semi-synchronous replication improves data security but increases latency. 3) Group replication supports multi-master replication and failover, suitable for high availability requirements.

The EXPLAIN statement can be used to analyze and improve SQL query performance. 1. Execute the EXPLAIN statement to view the query plan. 2. Analyze the output results, pay attention to access type, index usage and JOIN order. 3. Create or adjust indexes based on the analysis results, optimize JOIN operations, and avoid full table scanning to improve query efficiency.

Using mysqldump for logical backup and MySQLEnterpriseBackup for hot backup are effective ways to back up MySQL databases. 1. Use mysqldump to back up the database: mysqldump-uroot-pmydatabase>mydatabase_backup.sql. 2. Use MySQLEnterpriseBackup for hot backup: mysqlbackup--user=root-password=password--backup-dir=/path/to/backupbackup. When recovering, use the corresponding life

The main reasons for slow MySQL query include missing or improper use of indexes, query complexity, excessive data volume and insufficient hardware resources. Optimization suggestions include: 1. Create appropriate indexes; 2. Optimize query statements; 3. Use table partitioning technology; 4. Appropriately upgrade hardware.

MySQL view is a virtual table based on SQL query results and does not store data. 1) Views simplify complex queries, 2) Enhance data security, and 3) Maintain data consistency. Views are stored queries in databases that can be used like tables, but data is generated dynamically.

MySQLdiffersfromotherSQLdialectsinsyntaxforLIMIT,auto-increment,stringcomparison,subqueries,andperformanceanalysis.1)MySQLusesLIMIT,whileSQLServerusesTOPandOracleusesROWNUM.2)MySQL'sAUTO_INCREMENTcontrastswithPostgreSQL'sSERIALandOracle'ssequenceandt

MySQL partitioning improves performance and simplifies maintenance. 1) Divide large tables into small pieces by specific criteria (such as date ranges), 2) physically divide data into independent files, 3) MySQL can focus on related partitions when querying, 4) Query optimizer can skip unrelated partitions, 5) Choosing the right partition strategy and maintaining it regularly is key.

How to grant and revoke permissions in MySQL? 1. Use the GRANT statement to grant permissions, such as GRANTALLPRIVILEGESONdatabase_name.TO'username'@'host'; 2. Use the REVOKE statement to revoke permissions, such as REVOKEALLPRIVILEGESONdatabase_name.FROM'username'@'host' to ensure timely communication of permission changes.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Atom editor mac version download
The most popular open source editor

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft

Notepad++7.3.1
Easy-to-use and free code editor

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function
