checkpoint 13500

written and guaranteed to be rolled back, making it possible to roll back all modifications if the commit fails. The redo information here is actually the redo information of the rollback segment. Write-priority protocols guarantee the atomicity of transactions in the database transaction layer. 3.3 Transaction Submission When a transaction commits, a SCN is assigned and a redo log record containing that SCN submission is established. The commit process does not end when some redo records (i

MySQL Engine Features-InnoDB redo log roamingPreface InnoDB has two very important logs: undo log and redo log. The former is used to ensure the atomicity of transactions and the MVCC of InnoDB, and the latter is used to ensure transaction persistence. Like most relational databases, InnoDB records physical changes to data files and ensures that logs are always logged first, that is, the so-called WAL, before the persistent data files, ensure that the previous redo logs have been written to the

large extent. 34 what is the difference between temporary tablespace and permanent tablespace?A: A temporary tablespace is used for temporary objects such as sorting structures and permanent tablespacesUsed to store the 'true' objects (such as tables and rollback segments) 35. What is the name of the tablespace automatically created when a database is created?Answer: System tablespace. 36. In Oracle databases, there are three types of checkpoints Based on the execution time. First, the databa

DBWn: the Database Block Writer is responsible for the background process of writing dirty blocks to the disk. CKPT: The Checkpoint Process is only the header of the file for updating the data file to assist in creating the Checkpoint Process (DBWn ). LGWR: Log Writer is responsible for refresh and output the content in the SGA to the disk. In fact, these three processes are designed to better accomplish on

file information. Redo logs and archive logs. Backup set and backup file information Check Point and SCN information. When the database is shut down normally, the SCN value in the control file In the data file information section of the control file, each data file has a Checkpoint SCN and Stop SCN, which must be verified when the database is started. We know how the database controls the SCN in the file when the consistency is disabled? 1. Close t

process writes dirty cache blocks to data files; C. When a checkpoint LGWR process occurs, it notifies the DBWn process to perform write operations; D. When a tablespace is in the backup mode, offline, or read-only state; E. When the DBWn process times out (Time_out), that is, it is not started in about 3 seconds. Ü role: A. Manage High-Speed buffers to ensure that the server process can always find idle cache blocks to save data blocks read from dat

the reader to view the number of Wals that the continuous running database has committed the changes to at the same time. the transaction can also be appended to the end of a single Wal File Operation Of course, the append of a transaction to be finally transmitted to the wal file is copied back to the original database. Moving the wal file back to the database is called a "checkpoint" Another method is that the difference between rollback and the Wi

a single extraction process4, the transmission process and the extraction process needs one by one correspondence;2.3. Splitting steps1. Stop Extract Process2. Stop DataPump ProcessGgsci> INFO Datapump_nameEXTRACTDPEF last Started 2011-01-28 12:34 Status RUNNINGCheckpoint Lag 00:00:00 (updated 00:00:05 ago)Log Read Checkpoint File./dirdat/ef0000102011-01-28 12:47:45.000000 RBA 148645Until the RBA number does not change, can stop3. Stop Replicat Proce

This articleArticleThis is the second article in the series, in case you have not read the first article. The address of the previous article is as follows: Transaction logs in SQL Server (I)-physical and logical architecture of transaction logs Introduction Each SQL Server database records the corresponding logs to the log files according to the order of the modified data (insert, update, delete. SQL Server uses the write-Ahead Logging Technology to ensure the atomicity and durability of

When using Microsoft Exchange Server 2003, you must note the differences between recovery and recovery. Restoration refers to the restoration of databases and log files to the server. Restoration refers to the replay of transaction logs to the recovered database. There are two forms of recovery: Soft Recovery refers to the log replay process when the database is reloaded unexpectedly after it is stopped, or when the transaction log is replayed to the offline backup of the database. The replay p

When using Microsoft Exchange Server 2003, you must note the differences between recovery and recovery. Restoration refers to the restoration of databases and log files to the server. Restoration refers to the replay of transaction logs to the recovered database.There are two forms of recovery:Soft Recovery refers to the log replay process when the database is reloaded unexpectedly after it is stopped, or when the transaction log is replayed to the offline backup of the database.The replay proce

About the SCN understanding System Checkpoint SCN (V$database (checkpoint_change#)) Data file Checkpoint (V$datafile (checkpoint_change#)) Data file termination SCN (V$datafile (last_change#)) Checkpoints stored in data files Start SCN (V$datafile_header (checkpoint_change#) 1. System Checkpoint SCN When a checkpoint

MySQL InnoDB log mechanism in-depth analysishttp://blog.csdn.net/yunhua_lee/article/details/65678691.1.Log CheckpointInnoDB transaction log refers to redo log, which is called log, stored in the log file ib_logfile* inside. InnoDB There is another log of undo logs, but the undo log is stored in the shared tablespace (ibdata* file).Because log and checkpoint are closely related, these two parts are analyzed together.Noun Explanation: LSN, log sequence

1. Example of a calculator (manually add and write the result to the log file) systemutil. run "C: \ windows \ system32 \ calc.exe", "", "C: \ WINDOWS \ System32", "open" window ("Calculator "). winbutton ("1 "). click window ("Calculator "). winbutton ("+ "). click window ("Calculator "). winbutton ("2 "). click window ("Calculator "). winbutton ("= "). click 'Insert --> output value --> standard output value -->... window ("Calculator "). winedit ("edit "). output

Brush to backpack, backpack is a kind of problem, open a total knot record affixed1 01 knapsack problemTest instructions: There are n items and a backpack with a capacity of V. The cost of placing the article I is CI, the value is WI. Solve what items are loaded into the backpack to maximize the valueidea: define the state with sub-problem: f[i,v] means the maximum value that the first I item can get in a backpack with a capacity of V. The state transfer equation is:F[i,v]=max (F[I,V],F[I-1,V-CI

A. Practical Byzantine fault tolerance 1. What's its checkpoint? We will refer to the States produced by the execution of these requests as checkpoints and we will say that a checkpoint with a proof is a stable checkpoint. when the replication code invokes the make_checkpoint upcall, snfsd gets all the copy-on-write bits and creates a (volatile)

simultaneously write these two log files, LGWR will not write different groups of log files at the same time.In different cases, when the redo log is invalid, the LGWR lock uses the following actions:1) LGWR can write at least one member file in the group: The write operation is completed normally. LGWR writes accessible member files to the group and ignores inaccessible member files.2) during log switching, LGWR cannot access the next group because the group needs to be archived: temporarily s

:/u01/11.2.0/grid/crs/install/crsconfig_paramsUser ignored prerequisites during installationFailed to write the checkpoint: ' Rootcrs_stack ' with Status:start. ErrorCode is 256Failed to add (property/value):(' version/' 11.2.0.3.0 ') forCheckpoint:rootcrs_stack. Error Code is 256Failed to write the checkpoint: ' Rootcrs_param ' with Status:start. ErrorCode is 256Failed to write contents of Pfile:/u01/11.2.

().-Consistency issues with logical logsThe consistency of the logical log is very complex, and why does the undo log use logical logging?Since redo log uses physiological logs and MTR, you can guarantee that the redo log will be re-completed upon recovery.Data is consistent. When you do undo, you don't have to think about it.04–checkpointTheoretically, if the MySQL database InnoDB storage engine buffer is large enough, you do not need to persist the data itself. Re-execute all redo logs againY

recovery Command provided by the systemThe specific recovery operation is still completed by the DBMS.Two ProblemsSearching the entire log takes a lot of timeREDO processing: Re-execution wastes a lot of timeCheckpoint Recovery TechnologyAdd a checkpoint record to the log file)Add a file to start againThe recovery subsystem dynamically maintains logs during logon log filesCheckpoint Record Content1. Create a list of all ongoing transactions at the