sql deadlock

Recently, the data migration tool is almost completed. Today, the connection pool is changed to C3P0, and a problem is found, A deadlock occurs when C3P0 of multiple data sources is configured to obtain connections of different data sources at the same time. 1. Run the following code and use JProfiler for testing. The Code packagecom. highgo. test. c3p0dea is deadlocked. Recently, the data migration tool is almost completed. Today, the connection pool

1. Critical Area problem of Process Synchronization and Peterson Algorithm 2. semaphore mechanism (pv operation) for Process Synchronization and three typical synchronization problems This article introduces many issues of process synchronization in process management. The following describes the deadlock issues in process management and their solutions.1. What is a deadlock? In a multi-channel programming

Solve a deadlock problem in mysql Here we are talking about innodb deadlocks! I have found a lot of other commands on the Internet to view the deadlock information. This can be used later: Show engine innodb status; (varies with the mysql version) If there is a deadlock after this command is executed on the mysql Command Line The following section appears: -----

with 4 threads: Thread 2 locks B, waits for C thread 3locks C, Waits for D thread 4locks D, waits for A Thread 1 waits for thread 2, thread 2 waits for thread 3, thread 3 waits for thread 4, thread 4 waits for thread 1.deadlock of the databaseA more complex deadlock scenario occurs in a database transaction. A database transaction may consist of multiple

Recently learn to test MyBatis, a single deletion and change check are no problem, the last use MVN test when found a few problems: 1.update failed because of database deadlock 2.select waiting because the connection connection pool was used up and needed to wait Get 1. To dare to explore, perseverance is victory. Just see the error when the direct Meng, because the error can not see out, belong to the frame internal error, in hesitation is not di

). Insert and update concurrency, with nonclustered indexes.The deadlock principle is the same as 4.(6) Delete and update concurrency.Principle of the same 2.Deadlock Case Connection:InnoDB Next-key Lock-triggered deadlock:Http://www.cnblogs.com/xhan/p/3701459.htmlDeadlock caused by unique key:Http://www.cnblogs.com/sunss/p/3166550.htmlDelete deadlock in MySQLhtt

is to solve deadlocks.Deadlock Handling Method Mysql-uxxx-pxxx-h Server ip Address -- port = server port; (if the server is configured with ip address and port access, it must contain ip address and port) Mysql> show processlist; # view the SQL statement being executed (show full processlist; view all SQL statements)Mysql> kill id # kill the SQL process;If too m

lock wait time. The lock wait is different from the DB2 deadlock. the deadlock is caused by improper program concurrency. You need to adjust the program concurrency mechanism. The lock wait is a performance problem and may need to adjust the SQL statement of the program. Whether it is a deadlock or lock wait, the dat

of various locks Table-level locks are more suitable for queries, and only a few applications update data based on index conditions, such as Web applications. Row-level locks are more suitable for applications with a large number of concurrent data updates based on index conditions and concurrent queries, such as some online transaction processing systems. 4. deadlock Two or more processes are waiting for each other due to resource competition duri