Category: MySQL Basics
-
InnoDB Multi-Versioning
InnoDB is a multi-versioned storage engine: it keeps information about old versions of changed rows, to support transactional features such as concurrency and rollback. This information is stored in the tablespace in a data structure called a rollback segment (after an analogous data structure in Oracle). InnoDB uses the information in the rollback segment to perform the undo operations needed in a…
//
-
MySQL Physical (Raw) Vs Logical Backups
Physical backups consist of raw copies of the directories and files that store database contents. This type of backup is suitable for large, important databases that need to be recovered quickly when problems occur. Logical backups save information represented as logical database structure (CREATE DATABASE, CREATE TABLE statements) and content (INSERT statements or delimited-text files). This type of…
//
-
MySQL Full Vs Incremental Backups
A full backup includes all data managed by a MySQL server at a given point in time. An incremental backup consists of the changes made to the data during a given time span (from one point in time to another). MySQL has different ways to perform full backups, such as those described earlier in this…
//
-
MySQL Full Versus Point-in-Time (Incremental) Recovery
A full recovery restores all data from a full backup. This restores the server instance to the state that it had when the backup was made. If that state is not sufficiently current, a full recovery can be followed by recovery of incremental backups made since the full backup, to bring the server to a…
//
-
SHOW PROCESSLIST Statement
The MySQL process list indicates the operations currently being performed by the set of threads executing within the server. The SHOW PROCESSLIST statement is one source of process information. For a comparison of this statement with other sources, see Sources of Process Information. If you have the PROCESS privilege, you can see all threads, even those belonging to other users.…
//
-
MySQL Uptime
MySQL Uptime SELECT VARIABLE_VALUE AS Uptime_seconds, NOW() AS “Now”, NOW() – INTERVAL VARIABLE_VALUE SECOND AS “Up since”, DATEDIFF(NOW(), NOW() – INTERVAL VARIABLE_VALUE SECOND) AS “Uptime_days” FROM performance_schema.session_status WHERE VARIABLE_NAME = ‘Uptime’; Output Example: +—————-+———————+—————————-+————-+ | Uptime_seconds | Now | Up since …
//
-
MySQL join_buffer_size, sort_buffer_size, read_buffer_size and read_rnd_buffer_size
join_buffer_size, sort_buffer_size, read_buffer_size read_rnd_buffer_size These four buffers are allocated per connection. So think twice before alerting. For example, if you set join buffer size=2 M and max connections=800, MySQL will allocate an extra 2 M per connection (2 M x 800). The same is true for the remaining three buffers. Again, everything is per-connection. In almost…
//
-
innodb_change_buffer_max_size
With MySQL 5.6.2, you can set the maximum size of the change buffer as a percentage of the total size of the buffer pool using the innodb change buffer max size configuration option. The default value for innodb change buffer max size is 25. The maximum number of characters is 50. On a MySQL server…
//
Search
Categories
- Azure (7)
- About Us (1)
- Azure SQL Database (6)
- My SQL (53)
- About Us (1)
- DBMS Concepts (20)
- Handbook (1)
- MySQL Architecture (19)
- MySQL Basics (29)
- MySQL L1 (14)
- Oracle (34)
- PostgreSQL (37)
- About Us (1)
- DBMS Concepts (21)
- PG Hand Book (1)
- pg_ High Availability (4)
- pg_Backup (4)
- pg_basic (11)
- SQL Server (132)
- About Us (1)
- Azure SQL Database (4)
- Backup and Recovery (17)
- Backup Tools for SQL Server (3)
- DBA Worries Continued (27)
- DBMS Concepts (28)
- High Availability (12)
- Installation and Configuration (23)
- L1 DBA (59)
- Monitoring (17)
- Performance Tuning (29)
- Power Shell Script (6)
- Security (12)
- SQL DBA Hand Book (2)
- SQL Scripting (16)
- SQL Server Reporting Services (2)
- Uncategorized (3)