Category: MySQL Basics
-
CPU Components
CPU consists of 6 main components: 1. CU Control unit 2. ALU Arithmetic logic unit 3. Registers 4. Cache 5. Buses 6. Clock All the components work together to allow processing and system control. Control Unit (CU) It fetches, decodes, and executes instructions. It issues control signals that control hardware. It moves data around the…
-
Cache Memory
Hey guys, In this blog I am going to explain you about Cache Memory Cache is a small amount of high-speed random-access memory (RAM) built directly within the processor. It is used to temporarily hold data and instructions that the processor is likely to reuse. This allows for faster processing as the processor does not…
-
Slow query log purge in MySQL
There are manly 3 steps… 1. Rename existing log file with _old. 2. Connect mysqladmin using socket and use flush-logs. 3. Delete _old file created in first step. Get the show query log location: mysql> show variables like slow_query_log %’; Get the socket file location: mysql> show variables like ‘socket%’; In my case I got…
-
Enable Data Load Local InFile
We were getting below error at the time of loading data into MySQL. Error: Programming Error: 3948 (42000): Loading local data is disabled; this must be enabled on both the client and server sides. Solution: Check the status of local_infile variable in MySQL… > show variables like ‘%local%’; +—————+——-+ | Variable_name | Value | +—————+——-+ |…
-
MySQL master – slave replication setup
Hi guys, I hope you are doing great. Today here I am going to explain about MySQL master – slave replication setup. For the setup I have two servers clota-labl01 and clota-labl02. Here on clota-labl01 I am going to setup master and clota-labl02 as slave DB. Connect master server… ++++++++++++++++++++ clota-labl01 ++++++++++++++++++++ my.cnf configuration… =================…
-
Out of Memory Killer in Linux OS
In Linux systems, MySQL generally has a concept called Out of Memory killer OOM controlled by the kernel. This is to prevent the possible runaway process in OS to avoid race conditions and a server crash. Since MySQL and its optimized memory buffers are memory hogs, the OS may often kill the mysqld process to…
-
Deterministic and Nondeterministic Functions
Deterministic functions: Deterministic functions always result in the same output every time they are called with a fixed set of input values and given the same condition of the database. For example, AVG() function always results the same result given the qualifications stated above. Nondeterministic functions: Nondeterministic functions result in different output each time they…
-
Index in MySQL
Index Info… SELECT DISTINCT TABLE_NAME, INDEX_NAME,COLUMN_NAME, index_type FROM INFORMATION_SCHEMA.STATISTICS WHERE TABLE_SCHEMA =’thinklouder_optimization’; SHOW INDEXES FROM table_name IN database_name; —————————————————— OPTIMIZE TABLE tbl; will rebuild the indexes and do ANALYZE; it takes time. —————————————————— ANALYZE TABLE tbl; is fast for InnoDB to rebuild the stats. With 5.6.6 it is even less needed. —————————————————— Read the…
-
My SQL Innodb Cluster Setup
Server List clota-dbl05 @@version 8.0.32-commercial 192.168.0.156 My SQL root password Secure@123 ——————————————————————- ota-dbl06 <cota-dbl06> @@version 8.0.33 192.168.0.197 My SQL root password Secure@123 ——————————————————————- clota-dbl07 192.168.0.195 @@version @@version 8.0.33 My SQL root password Secure@321 ——————————————————————- Step 1: Modify /etc/hosts with IP and server_name on all the nodes… Like below vim /etc/hosts 192.168.0.156 clota-dbl05 192.168.0.197 ota-dbl06 192.168.0.195 clota-dbl07…