lock8

According to the description in oracledocument, V $ sysstat stores the resource usage of the entire instance (instance-wide) from the moment the database instance runs. Similar to V $ sesstat, this view stores the following statistics:1>. Event Occurrence Count statistics (for example, user commits)2>. Total column of data generation, access, or operation (such as redo size)3>. If the value of timed_statistics is true, the total time spent on the operation is counted (for example, CPU used by

source=1;//Resource access Lock8 9 writer ()Ten { One while(1) A { - P (W_mutux); - if(write_count==0) theP (rw);//the acquisition will not be released as long as the write process comes in . -write_count++; - V (W_mutux) - +P (resouce);//write-time mutex must be a resource exclusive lock - writing sth; + V (resouce); A at P (W_mutux); -write_count--; - if(write_count==0) - V (rw); - V (W_mutux); - } in } -

the content of this article:1.paramiko module Use2. Introduction to Processes and threads3.python Methods for calling Threads4.join-Waiting for thread execution5. Daemon Threads6.GIL-Global Interpreter lock7. Mutual exclusion Lock8. Signal Volume9. Events10. QueuesOne, Paramiko module useIntroduction to 1.paramiko Modules? Paramiko is an SSH-based connection to a remote server and performs related operations (Sshclient and Sftpclinet, one is a remote

of TIMED_STATISTICS is true, the total time spent on the operation is counted (for example, CPU used by this session)Common columns in the v $ sysstat View:L STATISTIC #: IDL NAME: Statistical Item NAMEL VALUE: resource usageThis view also has a column of class-statistical categories, which are rarely used. The following information is displayed:1. Example Activity2 represents the Redo buffer Activity4 represents the lock8 indicates data buffer Activ

lock8 indicates data buffer Activity16 represents OS Activity32 represents parallel activities64 represents Table Access128 indicates debugging information [Q] how to kill a specific database session[A] alter system kill session 'sid, serial #';OrAlter system disconnect session 'sid, serial # 'immediate;In Windows, Oracle can also be used to kill a thread (an oracle process)On Linux/Unix, kill can be used directly to kill the OS process correspondi

The so-called Singleton is: an application (APP) has only one instantiation object, this object is a singleton, generally used for music player and Tool classHere we teach you how to create a singleton manually, one is to use mutexes, and the other is to take advantage of Dispatch's one-time execution.1//Create a singleton by mutual exclusion lock2+(instancetype) Sharednetworktools3 {4 //static modifier5 StaticNetworktools *tools =Nil;6 //To determine if an instantiated object exists

Learned from dynamic performance tablesFirst Article --v$sysstat 2007.5.23As described in Oracledocument, V$sysstat stores the resource usage of the cumulative full instance (Instance-wide) Since the moment the DB instance runs.similar to V$sesstat , the view stores the following statistics:1>: Statistics on the number of occurrences (e.g. user commits)2> The total column of data generation, access, or operation (e.g. redo size)3> If the Timed_statistics value is true, the total time spent execu

/Heavyweight lockjdk1.5 introduces the lock escalation mechanism to achieve efficient synchronizedBiased lock: If one of the synchronization code is accessed by a thread, the thread acquires the lock automaticallyLightweight Lock: When the lock is biased, another thread accesses the synchronization code, the bias lock rises to a lightweight lock, and the other thread acquires the lock in the spin form, without blockingHeavy lock, Lock is a lightweight lock, another thread spins a certain number

state3. Can stop the thread--exception method4. Stop in slumber5. The thread that can stop--the violence stops6. Method Stop () and Java.lang.ThreadDeath exception7. Bad consequences of releasing the lock8. Use return to stop the threadEight, suspend thread1.suspend and the use of the Resume method2.suspend and the disadvantage of the resume method--monopoly3.suspend and the disadvantage of the resume method--out of syncNine, Yield () methodX. Priori

1. Use sp_lock to see if the output information LockType contains-BLK characters, indicating that the lock on the page table_id the current table is blocking other processes2. By viewing master. Syslocks system tableCasesID dbid page Type SPID class FID context row loid----------- ------ ----------- ------ ------ -----512004855 6 0 3 Non Cursor Lock 0 0 0 26512004855 6 0 4 Non Cursor Lock 0 0 0 24512004855 6 0 3 Non Cursor Lock 0 0 0 20512004855 6 793 261 Non Cursor lock 0 8 0 26 The current blo

1 /// 2 ///Conditional Variable Mode3 ///let threads execute on condition4 /// 5 Public Sealed classConditionvariablepattern6 {7 //two threads using the same lock8 Private ReadOnly ObjectM_lock =New Object();9 Ten //Compound condition (here is just a simple Boolean type) One Private BOOLM_condition =false; A - Public voidThread1 () - { the //acquires an exclusive lo

1. Why should we use Spring ?2. Explain the IOC3. Introduce SPRINGMVC4. The difference betweenMybatis and Hibernate5. Describe the transactions and indexes of the database6. transaction level of the database7. Introduce the locking of the database, such as optimistic lock , pessimistic lock8. How to design database tables to store billions of data9.linux Library functions and kernel callsLinux Basic instructions11. What is a Java Virtual machine12.jav

execute.Thread.setpriority (): Sets the priority of the thread. Priority, the longer the CPU is scheduled.Max = 10Normal = 5Min = 0;The value range is between 0---10.Thread.seleep (): The Sleep of the thread. Unlike yield, it is dormant. Can be awakened.Methods to stop a thread: The old way of realizing it before Stop/destory method. Causes deadlocks (to understand deadlocks in a way that combines iterators and collections) Now the new way: 6: Why to use

Tags: ATI nbsp nap RAC Status LOB snapshot control masterOpen General_log log, get mysqldump EXECUTE statement Show VARIABLES like ' general_log% ' set GLOBAL general_log=on Execute backup command Mysqldump--single-transaction-uroot-pdmysqlbadmin--master-data=2-a -r-e >/data/test.sql Get General_log Log 161109 14:48:25 8 Connect [email protected] On 8 query/*!40100 set @ @SQL_MODE = ' * */8 Query/*!40103 SET Time_zone= ' +00:00 ' */8 query FLUSH/*!40101 LOCAL */TABLES 8 QueryFLUSH TABLES with R