With generic asynchronous MySQL Replication we often use skip_slave_counter to tackle / skip anonymous transactions which creates errors or halt MySQL Replication. But if we try to skip slave counter whilst GTID_MOD is ON we get following error. ERROR 1858 (HY000): sql_slave_skip_counter can not be set when the server is running with @@GLOBAL.GTID_MODE = ON. […]
MySQL replication by default is asynchronous. The master writes events to its binary log but does not know whether or when a slave has retrieved and processed them. With asynchronous replication, if the master crashes, transactions that it has committed might not have been transmitted to any slave. Consequently, failover from master to slave in […]
Memory Allocation in UNIX: UNIX uses C dynamic memory allocation libraries for memory allocation. Namely malloc, realloc, calloc and free are used. Functions of these liberaries are given below. Function Description malloc allocates the specified number of bytes realloc Increases or decreases the size of the specified block of memory. Reallocates it if needed calloc allocates the specified number […]
The following system variables, status variables, and options have been deprecated in MySQL 8.0. Deprecated : expire_logs_days: Purge binary logs after this many days. Added: binlog_expire_logs_seconds: Sets the binary log expiration period in seconds.This is to replace the expire_logs_days. Deprecated : innodb_undo_tablespaces: The number of tablespace files that rollback segments are divided between. Deprecated as […]
Invisible Indexes Invisible indexes is new feature added in MySQL 8.0. This feature can help us to mark an index as unavailable for use by optimizer. This means that index will still be maintained and kept up to date in metadata dictionary as data is modified. These marked indexes are not permitted to be used […]
Reduce startup and shutdown time by using warm up innodb buffer pool For database servers having large memory utilisation and have big innodb_buffer_pool_size , it takes longer to stop and start the instance. This is because more data and indexes stored in huge innodb_buffer_pool. This data and indexes are used by queries running on the […]
Few issues I came across when dealing with MySQL performance. Let us go through these problems one by one. Swap usage: MySQL loves memory as almost all databases do but MySQL tries to utilise all the possible available memory. In order to restrict MySQL to use allocated memory resources we should implement following:- Swapiness Swappiness […]
Oracle VS MySQL file architecture For Oracle database administrator, when it comes to learn new technology it always starts from comparison with respect to physical or logical architecture. Physical file architecture comparison is given below , I hope it will be very useful for Oracle or MySQL database administrators who want to learn either of […]
mysql_config_editor (utility to configure authentication information for connecting to MySQL server) Introduction: Normally we connect to MySQL using username , password , socket or host etc as shown below. bash-4.2$ mysql -uroot -p -h testmysql -S /var/log/mysql.sock Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 40974 […]
Read files using arrays in Bash script I have following file with some numeric contents in it bash-4.2$ cat /tmp/araytest.txt 1 2 3 4 5 6 7 8 9 10 11 12 13 14 If we would like save the file contents in Array. We can using following method. while read LINE do ARRAY+=(“$LINE”) done […]
