There are only two difficult problems in the traditional RDBMS domain: query optimization and concurrency control. This blog discuss various aspects of the latter in Mysql. Isolation levels The b...

Tricks Use class... Args to mimic Python *args and **kwargs. See example.

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. 2024-12-05 Thu I always came cross real models. For example today https://2023.splashcon.org/details/iwaco-2023-papers/5/Borrow-checking-Hylo. Stay focused and ...

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...