General Query Log on FromDual GmbH

MariaDB Connection ID

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 29 Nov 2021 15:09:27 +0000

The MariaDB Connection ID exists since long ago. So why bother about the Connection ID? Because it is interesting and you can do some interesting things with the Connection ID like tracking statements in your connections and find where they come from your application code.

MariaDB Log Rotation

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 25 Nov 2019 17:46:40 +0000

Modern Linux Systems have a mechanism called logrotate to rotate different log files.

Enable General Query Log per Connection in MariaDB

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 10 Jul 2019 20:27:58 +0000

The General Query Log in MariaDB is a Log (file or table) that logs every statement sent from the Application to the MariaDB Database Server from the Connect Command to the Quit Command. A simple example you can find here:

How to recover deleted tablespace?

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 14 Nov 2014 22:56:17 +0000

Sometimes, MySQL tablespace file(s) might be deleted by mistake, e.g. delete the shared tablespace (ibdata1) or an individual tablespace (table_name.ibd).

Impact of General Query Log on MySQL Performance

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 08 Apr 2014 11:19:06 +0000

Sometimes, it is required to enable the General Query Log (which is disabled by default). If the General Query Log is enabled the server writes to this log information when clients connect or disconnect, and each SQL statement received from the client.

General Query Log & Slow query log is not working

oli.sennhauser@fromdual.com (Oli Sennhauser) — Thu, 20 Mar 2014 11:48:10 +0000

I have enabled the General Query Log and the Slow Query Log in MySQL 5.6.13 in windows server. File is created but sql statement are not capturing. This is production server now its not possible to restart.

user password change date

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 30 Oct 2013 11:37:23 +0000

Dear friends, Is there is any command to check when user and password created in MySQL user table. I want command for user logins last password change date and password created date. in MSSQL we are able to take where as in MySQL unable to take. Kindly help me

MySQL Query Cache does not work with Complex Queries in Transactions

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 29 Jun 2011 13:28:27 +0000

We did recently a review of one of our customers systems and we found that the Query Cache was disabled even thought it had significant more read than write queries.
When we asked the customer why he has not enabled the Query Cache he mentioned a review that was done a few years ago and which stated that the Query Cache hit ratio was non optimal.
This was verified on a testing system which had the Query Cache enabled by accident.

MySQL Server Error Codes and Messages 1650 - 1699

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 06 Dec 2010 11:59:20 +0000

1600 - 1649 1700 - 1749

Error: 1650 SQLSTATE: HY000 (ER_SLAVE_IGNORE_SERVER_IDS)

Quick links to the MySQL documentation

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 15 Mar 2010 15:50:27 +0000

MySQL Statement Syntax

Data Definition Language (DDL) Statements

ALTER DATABASE	ALTER EVENT	ALTER LOGFILE GROUP	ALTER FUNCTION
ALTER PROCEDURE	ALTER SERVER	ALTER TABLE	ALTER TABLESPACE
ALTER VIEW	CREATE DATABASE	CREATE EVENT	CREATE FUNCTION
CREATE INDEX	CREATE LOGFILE GROUP	CREATE PROCEDURE	CREATE FUNCTION
CREATE SERVER	CREATE TABLE	CREATE TABLESPACE	CREATE TRIGGER
CREATE VIEW	DROP DATABASE	DROP EVENT	DROP FUNCTION
DROP INDEX	DROP LOGFILE GROUP	DROP PROCEDURE	DROP FUNCTION
DROP SERVER	DROP TABLE	DROP TABLESPACE	DROP TRIGGER
DROP VIEW	RENAME DATABASE	RENAME TABLE

Data Manipulation Language (DML) Statements

CALL	DELETE	DO	HANDLER
INSERT	LOAD DATA INFILE	REPLACE	SELECT
TRUNCATE TABLE	UPDATE

MySQL Utility Statements

MySQL Transactional and Locking Statements

START TRANSACTION	COMMIT	ROLLBACK	SAVEPOINT
ROLLBACK TO SAVEPOINT	LOCK TABLES	UNLOCK TABLES	SET TRANSACTION
XA Transactions

Account Management Statements

CREATE USER	DROP USER	GRANT	RENAME USER
REVOKE	SET PASSWORD

Table Maintenance Statements

ANALYZE TABLE	BACKUP TABLE	CHECK TABLE	CHECKSUM TABLE
OPTIMIZE TABLE	REPAIR TABLE	RESTORE TABLE

Plugin and User-Defined Function Statements

SHOW Statements

SHOW AUTHORS

Limitations of MySQL

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 15 Mar 2010 11:01:40 +0000

Often asked but informations are spread around: The limitations of MySQL.

MySQL Federated Storage Engine

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 13 Mar 2010 13:32:56 +0000

What is a Federated Table?

A Federated Table is a table which points to a table in an other MySQL database instance (mostly on an other server). It can be seen as a view to this remote database table. Other RDBMS have similar concepts for example database links.

FromDual consulting tool collection

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sat, 13 Mar 2010 11:37:13 +0000

The following tools we use sometimes for our consulting engagements…

We build a data warehouse from the General Query Log

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 31 Jan 2024 16:41:13 +0100

The design of a data warehouse differs from relational design. Data warehouses are often designed according to the concept of the star schema.