QEP: query execution plan Join straight join It is kind of option that forbid reordering tables when joining. According to official doc, This can be used for those (few) cases for which the ...

Some random thoughts or learnings. 2025-06-01 From “F. E. Allen. Control flow analysis. SIGPLAN Notices, 5(7):1–19, July 1970. Proceedings of a Symposium on Compiler Optimization.”: is this a...

Questions What is Mysql iterator executor

I am reading a good book “Database internals” by Alex Petrov. Below are some useful papers I read Ubiquitous b-tree Some useful resources: Alibaba’s database engine blogs http://mysql.ta...

Stored Procedures (sp). One trick of loading a stored procedure in a mysql shell is to use sourece command. You can check if a sp exists by show create procedure MY_PROC. This is a good post abo...

Mini transaction

Metadata lock #0 open_tables_for_query (thd=0xffff2c001050, tables=0xffff2c0fdd58, flags=0) at /code/mysql-server/sql/sql_base.cc:6729 #1 0x0000aaaaae2e4b80 in Sql_cmd_dml::prepare (this=0xf...

The literature seems have different meaning for DDL. Some refers it as Data Definition Language. Others may refer it data dictionary language. Online DDL Online DDL refers to do db migration with...

Configurations Mysql binary log is rotated. The threshold is controlled by max_binlog_size option. AWS RDS uses a stored procedure to control the retention period of binary logs CALL mysql.rds_sho...

File system: block vs sector Sector is the smallest unit a disk can read/write, so writing a sector is atomic. Sector size is usually 512 bytes. On the other hand, block size refers to the allocat...