Celery has a AMQP broker and an consumer backend. kombu Kombu is a messaging library that supports AMQP, redis, etc. It is basically an AMQP broker. I feel reading its user guide is super helpful...

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...

Template Argument Deduction For Function Calls The ultimate source of truth is temp.deduct.call. Let’s take a few examples. Example 1: cv-qualifier and reference type template <typename T>...

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...