Multi-Tenant on FromDual GmbH

Sharding with MariaDB MaxScale

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 19 Mar 2024 17:02:58 +0000

Overview

This feature should more or less work with MariaDB MaxScale 6.x.y, 22.08.x, 23.02.x, 23.08.x and 24.02.x. We have tested it with the latest MaxScale version 23.08.05, as we encountered problems with an older version (MXS-5026).

Sharding do-it-yourself

oli.sennhauser@fromdual.com (Oli Sennhauser) — Tue, 15 Feb 2022 12:18:26 +0000

As already mentioned earlier, we roughly have a hand full of customers which are playing with the though of sharding solutions. They typically have many different customers (clients, tenants) and the number of customers becomes so huge (thousands to millions) that one machine cannot cope with the load any more.

Sharding solutions

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 24 Jan 2022 15:38:51 +0000

Once in a year or so we get a request of a customer about MariaDB/MySQL sharding solutions. So here we have a list of sharding solutions we are currently aware of:

Table definition cache too small

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 15 Jul 2015 06:08:36 +0000

The number of table definitions (SHOW CREATE TABLE<br>G) that can be stored in the table definition cache (table_definition_cache). If you have a large number of tables (
> 400) in your database instance, you should consider a larger table definition cache to increase your database throughput and decrease your query latency.
The command SELECT COUNT(*) FROM information_schema.tables; shows you how many tables and thus table definitions you have. The global status Open_table_definitions is the current amount of open table definitions.

Table open cache too small

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 15 Jul 2015 06:04:36 +0000

The Table Open Cache (table_open_cache or old name table_cache) is a cache to store file handles for all threads. The actual value of cache entries can be seen with the global status of open tables (Open_tables).
Increasing table_open_cache increases the number of file descriptors (open_files_limit) that MySQL requires.
You can check whether you need to increase the Table Open Cache by checking Open_tables and Opened_tables. If the value of Opened_tables is large and you do not use FLUSH TABLES often (which just forces all tables to be closed and reopened), then you should increase the value of the table_open_cache variable.

How MySQL behaves with many schemata, tables and partitions

oli.sennhauser@fromdual.com (Oli Sennhauser) — Wed, 30 Nov 2011 15:35:28 +0000

Introduction

Recently a customer claimed that his queries were slow some times and sometimes they were fast.

Configuration of MySQL for Shared Hosting

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 22 Apr 2011 13:03:31 +0000

If you ask around about shared hosting setups with MySQL everybody is frightened. In fact it looks like shared hosting is one of the most difficult setups you can get.