MySQL 5.7.10 issues with Ruby on OSX 10.11.3 - mysql

Question

I successfully installed mySQL 5.7.10 and the mySQL gem for Ruby on my OSX 10.11.3 based system. I am trying now to run following code:
require 'mysql'
require 'cgi'
class MysqlSaver
def saveWordStats(globalWordStats,time)
con = Mysql.new 'localhost', 'x', 'x', 'x'
i = 0
for word in globalWordStats.keys[0..10000]
print "#{i}\r"
i+=1
stat = globalWordStats[word]
time = time
escaped_word = Mysql.escape_string(word)
begin
escaped_word = escaped_word.gsub("\\","")
escaped_word = escaped_word.gsub("/","")
escaped_word = escaped_word.gsub("-","")
escaped_word = "#{escaped_word}_word"
con.query("CREATE TABLE IF NOT EXISTS #{escaped_word}(percent DOUBLE, time INT)")
con.query("INSERT INTO #{escaped_word}(percent,time) VALUES('#{stat}','#{time}')")
rescue
puts "#{$!}"
end
end
con.close
puts "DONE"
end
end
This code works without any errors. I'am able to create tables and store values in my mySQL database. But however, if I try to create/store >= ≈10.000 values in my database with this code I am no longer able to connect to my mySQL server, after the script finished running:
mySQL.rb:5:in `new': Lost connection to MySQL server at 'reading initial communication packet', system error: 102 (Mysql::Error)
from /Users/david/Desktop/Birta2/mySQL.rb:5:in `saveWordStats'
from run.rb:84:in `<main>'
Also a restart of the mySQL server doesn't help (only a restart of my entire mac helps!).
After the error occurs I can find this strange line in the mySQL log file:
2016-02-11T18:20:51.177054Z 0 [Warning] File Descriptor 1098 exceedeed FD_SETSIZE=1024
Is there any way to fix this error?

Answer 1

FD_SETSIZE is the maximum number of files you can have open at once. If you're using InnoDB, each mysqld process keeps one file open per table in the active database, so it's easy to exceed if you have a large number of tables or a large number of processes. You can change some settings in my.cnf to fix this.
table_open_cache is the number of tables MySQL will try to keep open at once:
table_open_cache = 1000
max_connections is the maximum number of simultaneous connections (mysqld processes) to allow:
max_connections = 25
If your database has N tables, it's best to keep N * table_open_cache * max_connections less than FD_SETSIZE.