checkpoint vsec

help us reduce the size of the edits file and get an up-to-date Fsimage file, which will also reduce the pressure on the namenode. and secondary namenode is to help solve the above problems proposed, its responsibility is to merge Namenode edits to fsimage file. ：Working principle, I also repeat here: First, it periodically goes to Namenode to get edits, and updates to Fsimage. Once it has a new fsimage file, it copies it back to the Namenode. Namenode will use this new Fsimage

CPU speed and disk speed. The buffer pool is a large area of memory, which directly affects the overall performance of the DBMS. We strongly recommend that you install it in a 64-bit operating system to exceed the 32-bit maximum of 3G memory. A. the read record operation will FIX the page read from the disk to the buffer pool. When you read the same page again next time, check whether the buffer pool hits the page. Otherwise, read the disk. B. Write record operations first modify pages in the b

When talking about the transaction log, you have to talk about the Checkpoint, or CKP for short. The transaction log and the Checkpoint both exist for the rapid recovery of the database. We need to know what the checkpoint is and what it has to do with the transaction log. What does CKP do? In summary, data changes are not directly written to the mdf/ndf data fil

files in the current log group are not deletedAfter you force the log switch, you can delete the newly added log files.The following restrictions apply to deleting redo log files? You cannot delete a member of the current group to delete a command that performs a mandatory switchover redo log first: alter SYSTEM switch logfile? Activity log members cannot be deleted? Log members that are not archived cannot be deleted? Only one member of the current log group is or cannot be deletedLog group sw

Tags: Configure let yourself copy register with settings execution statement[Call Sqlplus.txt in 20170617]vim--//previously wrote an Emacs downgrade with Sqlplus article, has been wanted to learn Emacs, limited own vim, to learn it no interest, the original link is as follows:--//http://blog.itpub.net/267265/viewspace-1309032/--//actually VIM also has plug-in connection database, I feel not good, has not been so used.--//today when it comes to setting up vim-related settings, I find myself defin

transferred from: http://www.mongoing.com/archives/2540Mongodb-3.2 has been wiredtiger set up for the default storage engine, recently by reading the Wiredtiger source code (without understanding its internal implementation, reading code is very difficult, the code is too large, it is strongly recommended that the official more than the introduction of the article), Clarify the general principle of wiredtiger, and simple summary, do not guarantee that the content is correct, if there are questio

Generated in MySQL Cluster". Event logs is of the types listed here: Cluster log: Keeps a record of all desired reportable events for the Cluster as a whole. node log: A separate log which is also kept for each individual Node. Event log: The MySQL cluster generates logs by the kind (startup, shutdown, error, checkpoint, and so on), priority and severity events. A listener for a complete, reported event can be found in the section 1

that all the tables created by the script use the default names. You can also modify the default names of these tables. Iii. Test Note: (1) The user name and Object Name of the target database can be different from that of the source database. The key is that the configuration file must be correctly matched. (2) configure the source and target tnsnames to maintain interconnection. (Remember to start lsnrctl) Gg1: SQL> create user ssgg identified by oracle default tablespace users temporary tabl

Select name, checkpoint_change # from V $ database; Select name, checkpoint_change # from V $ datafile; Select name, last_change # from V $ datafile; Select name, checkpoint_change # from V $ datafile_header; select. name,. checkpoint_change #, B. checkpoint_change # from V $ datafile A, V $ datafile_header B where. name = B. name (+); select * from V $ tablespace; select * from V $ controlfile;/* Detailed description of the Oracle database SCN number: System

[In-depth analysis-eygle] Study Notes 1.1 buffer pool Principle Buffer cache is an important part of Oracle SGA. Generally, data access and modification must be completed through buffercache.When a process needs to access data, first determine whether the data exists in the memory. If the data exists in the buffer, you need to determine whether the data can be accessed directly or whether consistent reading needs to be constructed based on the data status;If the data does not exist in the buff

periodically wakes up and checks whether it needs to be used.Pmon is responsible for cleaning up and releasing resources and rolling back uncommitted transactions after a connection is aborted with an exception.Pmon is also responsible for monitoring other Oracle background processes and restarting these background processes if necessary.Pmon also registers the instance with the Oracle TNS Listener. Iii. dbwrDbwr (Database writing program) background processes are responsible for managing the c