Open_files_limit on FromDual GmbH

Increase file limit of a running process

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 19 Jun 2020 18:53:03 +0000

Asking stupid questions and googling for them is fun some times…

Linux system calls of MySQL process

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 15 Mar 2019 17:06:24 +0000

We had the problem today that a MySQL Galera Cluster node with the multi-tenancy pattern caused a lot of system time (sy 75%, load average about 30 (you really must read this article by Brendan Gregg, it is worth it!)) so we wanted to find what system calls are being used to see what could cause this issue (to verify if it is a TOC or a TDC problem:

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.

Could not increase number of max_open_files

oli.sennhauser@fromdual.com (Oli Sennhauser) — Sun, 28 Dec 2014 15:37:36 +0000

Hello all, on some Linux systems I get the following warning during my MySQL database start-up:

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.

MySQL trouble shooting

oli.sennhauser@fromdual.com (Oli Sennhauser) — Mon, 15 Mar 2010 11:46:39 +0000

Systemd related stuff for MariaDB and MySQL

oli.sennhauser@fromdual.com (Oli Sennhauser) — Fri, 06 Jan 2023 19:05:06 +0100

Systemd Notizen

Systemd paged per default nach less. Das ist ungewohnt und doof, weil es gegen allgemeines Linux-Verhalten verstösst. Abhilfe schafft: