all-database-solutions

[all-database-solutions]

Basics of MySQL InnoDB Cluster #database #databases #databaseadministration #databasemanagementsystem #databaseadministrator #databaseadmin #mysql #mssqlserver #mysqlworkbench

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Add or Remove a node in MySQL Innodb Cluster 

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MySQL Architecture - Part 2 - Locking and Concurrency #database #databases 

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MySQL Architecture - Part 1 - Basics

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Basic/Architecture SQL Server - Introduction #database 

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Oracle Partial recovery of Oracle database using RMAN #database #databases 

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Oracle Block Corruption - Detection and Resolution Any kind of corruption in database can lead to stand still operation of the organization and can cause sever impact to organisation. 

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Oracle Recovery scenario with Conventional hot backup Though ,Most of the Oracle DBA use RMAN to take backup but sometime understanding and knowing conventional hot backup recovery scenario will help to understand actual recovery process and improve knowledge and troubleshooting skills. 

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Backup & Recovery of Pluggable and Container database in 12c & 19C

With Oracle 12C onwards ,Oracle have come up with concept of multitenant database and with that there are multiple question with respect to taking backup & recovery of Container and

Pluggable database

. 

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Rebuild a corrupted/filed MySQL InnoDB Node 

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MSSQL Server Database’s Transaction Log Shrink 

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Oracle offers to unplug a PDB from one CDB and then plug into a different CDB. This will be another additional feature of PDB to give the highest availability and scalability the database systems may need in a cloud infrastructure environment. 

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For MySQL DBA its a common issue that one of the MySQL InnoDB Cluster node got corrupted. In that case we need to restore MySQL cluster node from mysqlbackup. Usually backup in MySQL InnoDB cluster is taken from one of the node in the cluster, if the node corrupted and backup node are same then you can simply restore the backup and start group replication.

[all-database-solutions]

Restoring a Failed member in InnoDB Cluster

Restoring a Failed member in InnoDB Cluster For MySQL DBA its a common issue that one of the MySQL InnoDB Cluster node got corrupted. In that case we need to restore MySQL cluster node from mysqlbackup. Usually backup in MySQL InnoDB cluster is taken from one of the node in the cluster, if the node corrupted and backup node are same then you can simply restore the backup and start group replication. But if the backup is node taken from the corrupted node ,We need to take some additional steps. In this blog we will discuss about the same scenario. Assume that we have three MySQL node mysqlhost01,mysqlhost02 & mysqlhost03. And the node which got corrupted is mysqlhost03 and backup is taken from the mysqlhost02.We will follow below steps to restore failed node mysqlhost03: 1) Move the MySQL backup from mysqlhost02 to mysqlhost03. 2) Change parameter group_replication_start_on_boot to false.set parameter group_replication_start_on_boot to false so that post MySQL restart Group replication services are not started automatically. Connect to mysqlhost03Server: mysql>select * from performance_schema.persisted_variables where variable_name like 'group_replication_start_on_boot%'; mysql>set persist group_replication_start_on_boot=false; 3) Stop MySQL on node mysqlhost03 and take backup of the existing auto.cnf and mysqld-auto.cnf . This is required to preserve the UUID for the mysqlhost03. 4) Remove all the data file and other database related files.Check the variables innodb_data_home_dir, innodb_log_group_home_dir, and innodb_undo_directory and make sure there is no files in these directory else backup restoration might fail. 5) Restore the backup mysqlhost02 to mysqlhost03. (Using Restore MySQL InnoDB Cluster from mysqlbackup) mysqlbackup --defaults-file=/etc/my.cnf \ --datadir=/var/lib/mysql \ --backup-image=/backups/my.mbi_2206_1429  \ --backup-dir=/tmp/restore_`date +%d%m_%H%M` copy-back-and-apply-log The command above assumes that the binary logs and relay logs on mysqlhost02 and mysqlhost03 have the same base name and are at the same location on the two servers. If these conditions are not met, you should use the --log-bin and --relay-log options to restore the binary log and relay log to their original file paths on mysqlhost03 . For example, if you know that on mysqlhost03  the binary log's base name is mysqlhost03 -bin and the relay-log's base name is mysqlhost03 -relay-bin, your restore command should look like:mysqlbackup --defaults-file=/etc/my.cnf \  --datadir=/var/lib/mysql \  --backup-image=/backups/my.mbi_***_****  \  --log-bin=mysqlhost03-bin --relay-log=mysqlhost03-relay-bin \  --backup-dir=/tmp/restore_`date +%d%m_%H%M` copy-back-and-apply-log 6) Restore auto.cnf and mysqld-auto.cnf files backed up step 3.For automatic rejoining of the restore node mysqlhost03 the UUID and other system variable must be same as is was before restore. In order to achieve same we need to restore the auto.cnf and mysqld-auto.cnf file. 7) Start MySQL on mysqlhost03 and verify parameter gtid_execute.MySQL> systemctl start mysqld Check the value of the gtid_execute and gtid in the backup_gtid_executed.sql file . These two values must be same, In order to start replication from the correct gtid value. If these value are not same,then the change the gtid_execute value to same as that of the value in the backu_gtid_executed.sql. mysql> SET SQL_LOG_BIN=OFF; mysql> SOURCE backup_gtid_executed.sql mysql> SET SQL_LOG_BIN=ON; Continue Reading... 

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Install MySQL 8.0 on ubuntu Server #database #databases 

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How to Clone Pluggable database within same Container Database

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Oracle convert Non-Container database to Pluggable database