Error Code: 23 Out of resources when opening file - mysql

Question

When I execute a query in MySQL, I get this error:
Error Code: 23
Out of resources when opening file '.\test\sample_table#P#p364.MYD' (Errcode: 24 - Too many open files)
MySQL version details:
VERSION 5.6.21
version_comment MySQL Community SERVER (GPL)
version_compile_machine x86_64
version_compile_os Win64
How to solve this problem?

Answer 1

The mysql error: Out of resources when opening file... (Errcode: 24) indicates that the number of files that msyql is permitted to open has been exceeded.
This limit is controlled by the variable open_files_limit. You can read this in phpMyAdmin (or the MySQL command line utility) with the statement:
SHOW VARIABLES LIKE 'open%'
To set this variable to a higher number, edit the /etc/my.cnf file and add the lines:
[mysqld]
open_files_limit = 5000

Answer 2

This answer explains the error code 24 (which is at the end of your error message).

Answer 3

If you happen (like me) to be doing some hacky server maintenance by running a single insert query for 35k rows of data, upping the open_files_limit is not the answer. Try breaking up your statement into multiple bite-sized pieces instead.
Here's some python code for how I solved my problem, to illustrate:
headers = ['field_1', 'field_2', 'field_3']
data = [('some stuff', 12, 89.3), ...] # 35k rows worth
insert_template = "\ninsert into my_schema.my_table ({}) values {};"
value_template = "('{}', {}, {})"
start = 0
chunk_size = 1000
total = len(data)
sql = ''
while start < total:
end = start + chunk_size
values = ", \n".join([
value_template.format(*row)
for row in data[start:end]
])
sql += template.format(headers, values)
start = end
Note that I do not recommend running statements like this as a rule; mine was a quick, dirty job, neglecting proper cleansing and connection management.