checkpoint vsec

CKPTQ: The data block in the Checkpoint Queue records the LRBA address of each data block. RBA: Redo Block Address (Address of the Redo log Block, which is equivalent to the rowid in the data file. You can use this Address to locate the Redo log Block) Consists of three parts: 4 byte + 4 byte + 2 byte Logfile sequence number (log file serial number) Logfile block number (Log File block number) Byte offset into the block (number of starting offset b

1. Sybase ASE transaction log Each database of Sybase ASE, whether it is a system database (master, model, sybsystemprocs, tempdb) or a user database, has its own transaction log, and each database has a syslogs table. Logs record user operations on the database, so if you do not need to clear the log, the log will continue to grow until the occupied space. You can run the dump transaction command to clear logs, or use the trunc log on chkpt option to clear logs automatically at intervals. Manag

the memo object, which is the "on" state. Because the initiator object's inner class memento implements the Mementoif interface, this inner class is the true type of the incoming memo object, so the initiator object can read out the internal state of the object using the private interface of the inner class memento.Multiple checkpointsThe schematic implementations of the white box and the black box given above are simple implementations that store only a single state, or they can be called only

only the latest SCN number, After a commit, this transaction slot can be used by another transaction. If the user roolback, the server process reconstructs the corresponding modified copy based on the transaction list and the SCN and the rollback segment address of the block in the data file block and DB buffer, and uses the original values to restore the modified but uncommitted changes in the current data file. If there are multiple "front images", the server process finds the rollback segme

Xlog file corresponding to the log can also be inferred from Current_xlog_location:Timeline 0000000000000045----> 000000010000000000000045(iii) LSN when used for recovery1) Use Pg_controldata to obtain control information from the controls file:Appledemacbook-pro-2:pg_xlog apple$ Pg_controldataPg_control version number:942Catalog version number:201510051Database system identifier:6451705940496018968Database Cluster State:in ProductionPg_control Last Modified: 4/9 10:52:12 2018Latest

file, it is also temporarily written to Redo Log_buffer, and then a certain event triggered before synchronization to the file.The size of the transaction log file is very much related to the overall IO performance of the Innodb. Theoretically, the larger the log file, the less refreshing the buffer pool needs to do, and the higher the performance. However, we can not overlook another thing, that is, when the system crash after the recovery.every modification to the data and indexes in the data

BackgroundIn Flink 1.5 above, it provides a new Kafka producer implementation:flinkkafkaproducer011, aligning with Kafka 0.11 above that supports transaction. Kafka transaction allows multiple Kafka messages sent by producer to deliver on an atomic the-and either all success or All fail. The messages can belong to different partitions. Before Flink 1.5, it provides exact once semantics only for its internal state via check point. However, if you write the stream state to external storage such as

As an important mechanism in Oracle, SCN (system Chang number) plays an important role in data recovery, data guard, streams replication, and synchronization between RAC nodes. Understanding the operating mechanism of SCN can help you gain a deeper understanding of the above functions. Before understanding SCN, Let's first look at how data changes in Oracle transactions write data files: 1. Start the transaction; 2. Find the required data block in the buffer cache. If no data block is found,

results allow the application to process the information background process. The processes used by the Oracle DB system are collectively referred to as "background processes". An Oracle DB instance can have multiple background processes. Common background processes in non-RAC and non-ASM environments-DBWn database write process-LGWR log write process-CKPT Checkpoint Process-SMON system monitoring process-PMON process monitoring process-RECO restorer

Tags: understanding of roll-forward and rollback for Oracle instance RecoverySome of the understanding of Oracle instance recovery, has been a misunderstanding, today by looking at relevant information and discussion with students, found their own mistakes, the results are as follows:Instance recovery: When the database is not properly shut down (power off or Shu abort, etc.), when you start the database, the database-related process automatically perform instance recovery without human interven

① DefinitionGrep is a row-level device that analyzes a row of information. If there is any information we need, the whole row is returned.② FunctionCompares string data to print the strings that meet your needs.③ FormatGrep [-acinv] [-- color = auto] 'query string' filenameParameters:-A: searches for data in the format of a binary file and a text file.-C: calculates the number of times a 'query string' is found.-I: case-insensitive-N: Output row number-V: displays the row without the 'query stri

Sybase ase transaction log Each database of sybase ase, whether it is a system database master, model, sybsystemprocs, tempdb) or a user database, has its own transaction log, and each database has a syslogs table. Logs record user operations on the database, so if you do not need to clear the Log, the log will continue to grow until the occupied space. You can run the dump transaction command to clear logs, or use the trunc log on chkpt option to clear logs automatically at intervals. Managing

-- color = auto: color of the keyword ④ example www.2cto.com eg01: find the flag of a checkpoint event [SQL] [oracle @ localhost bdump] $ grep-in -- color = auto 'checkpoint' alert_orcl.log 64: checkpoint is 446074 66: checkpoint is 446074 69: checkpoint is 446074 72:

TCP/IP to the target system. Capturing the process after each read data changes in the log and after the data is transferred to the target system, will write checkpoints, record the current completion of the capture log location, Checkpoint can make the capture process can be aborted and recovered from the checkpoint location to continue copying; The target system accepts data changes and caches it into th

Every database in Sybase SQL Server, whether it is a system database (Master,model, Sybsystemprocs, tempdb), or a user database, has its own transaction log, each of which has a syslogs table. Log records the user's modifications to the database, so if the command is not cleared, the log will grow up to fill up the space. Clear Log Available DUMP TRANSACTION command, or Open database option trunc Log on chkpt, the database automatically clears log at intervals. Managing database log is one aspec

Introduction to Oracle Goldengate Learning goldengate (2012-10-02-17:07:27) Tags: checkpoint data transfer Queue process Category: Goldengate Goldengate IntroductionGoldenGate TDM (transaction data management) software is a log-based structured data replication software, which through the analysis of the source database online log or archive log to obtain data deletion and change, and then apply these changes to the tar

startupFor DNA, the Oracle database control file is a very important file, which is a binary file that is automatically generated when the database is created, which records the status information of the database. No other user can modify the control file, and the database instance may modify the information in the control file only while the database is running. The control file mainly includes the following content:Database name, a control file can belong to only one database.Database creatio

bottleneck of HDFS operations, hadoop adopts the following method: No snapshot of the current file system is persisted, the list of actions for HDFS for the last period will be saved to an Editlog file in namenode. When the namenode is restarted, in addition to the load fsImage accident, the HDFS operation recorded in the EditLog file will be replaced to restore the final state before the HDFS restart. SecondaryNameNode periodically merges the HDFS operations recorded in the EditLog into a

Oraclesavepoint Introduction: by creating a checkpoint, we can roll back to any transaction that has created a checkpoint before the transaction is committed. The checkpoint does not exist after the transaction is committed. Oracle savepoint Introduction: by creating a checkpoint, we can roll back to any transaction th

Each database of Sybase SQL Server, whether it is a system database master, model, sybsystemprocs, tempdb) or a user database, has its own transaction log, and each database has a syslogs table. Logs record user operations on the database, so if you do not need to clear the Log, the log will continue to grow until the occupied space. You can run the dump transaction command to clear logs, or use the trunc log on chkpt option to clear logs automatically at intervals. Managing database logs is a m