Homebrew installed MariaDb too many open files

Submitted by clemens on Fri, 2020/11/13 - 9:08am

MariaDB broken

I did brew update/upgrade a while ago then weeks after that restarted MariaDB then days later tried to access MariaDB.

MariaDb too many open files

Trying to get info over the config file seems not easy.

ps -aef | grep maria

/usr/local/opt/mariadb/bin/mariadbd
 --basedir=/usr/local/opt/mariadb
 --datadir=/usr/local/var/mysql
 --plugin-dir=/usr/local/opt/mariadb/lib/plugin
 --log-error=/usr/local/var/mysql/Clemenss-MacBook-Pro.local.err
 --open-files-limit=2048
 --pid-file=Clemenss-MacBook-Pro.local.pid

Open files == 2048 ?

Brew config for MariaDB

Reading output from

brew services --help

Global it is not but let's check for sure

ls -l /Library/LaunchDaemons/

is interestingly showing OLD stuff but no MariaDb.

User specific

ls -l ~/Library/LaunchAgents/
...
homebrew.mxcl.mariadb.plist

contains

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>KeepAlive</key>
  <true/>
  <key>Label</key>
  <string>homebrew.mxcl.mariadb</string>
  <key>ProgramArguments</key>
  <array>
    <string>/usr/local/opt/mariadb/bin/mysqld_safe</string>
    <string>--datadir=/usr/local/var/mysql</string>
  </array>
  <key>RunAtLoad</key>
  <true/>
  <key>WorkingDirectory</key>
  <string>/usr/local/var</string>
</dict>
</plist>

That content does not match the result from the ps command ... huh?!?

brew services --debug --verbose start mariadb

showed indeed the same configuration.

Start MariaDB manually

Let's try to start from the command-line having `--open-files-limit=8192*

brew services stop mariadb

/usr/local/opt/mariadb/bin/mariadbd --basedir=/usr/local/opt/mariadb --datadir=/usr/local/var/mysql --plugin-dir=/usr/local/opt/mariadb/lib/plugin --log-error=/usr/local/var/mysql/Clemenss-MacBook-Pro.local.err --open-files-limit=8192 --pid-file=Clemenss-MacBook-Pro.local.pid
2020-11-13 11:32:59 0 [Note] /usr/local/opt/mariadb/bin/mariadbd (mysqld 10.5.5-MariaDB) starting as process 73990 ...
2020-11-13 11:32:59 0 [Warning] Could not increase number of max_open_files to more than 256 (request: 32190)
2020-11-13 11:32:59 0 [Warning] Changed limits: max_open_files: 256  max_connections: 151 (was 151)  table_cache: 200 (was 2000)
2020-11-13 11:32:59 0 [Warning] Setting lower_case_table_names=2 because file system for /usr/local/var/mysql/ is case insensitive

Make sure to kill mariadb nicely.

Fixing

Requires the following

Make ulimit settings system wide

launchctl limit maxfiles 30000 unlimited

vi /Library/LaunchDaemons/limit.maxfiles.plist
vi /Library/LaunchDaemons/limit.maxproc.plist

Add the same to your shell environment

launchctl limit maxfiles
    maxfiles    256            unlimited

The answer is puzzling ... the hard limit is unlimited.

Soft limits of 256 seems a little few for a database server

SELECT @@open_files_limit;
+--------------------+
| @@open_files_limit |
+--------------------+
|                256 |
+--------------------+

or IMHO nicer

SHOW VARIABLES LIKE 'open_files_limit';
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| open_files_limit | 256   |
+------------------+-------+

References

homebrew

mariadb

mysql

clemens's blog