Created
November 19, 2009 20:00
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MySQL server has gone away fix
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# If your workers are inactive for a long period of time, they'll lose | |
# their MySQL connection. | |
# | |
# This hack ensures we re-connect whenever a connection is | |
# lost. Because, really. why not? | |
# | |
# Stick this in RAILS_ROOT/config/initializers/connection_fix.rb (or somewhere similar) | |
# | |
# From: | |
# http://coderrr.wordpress.com/2009/01/08/activerecord-threading-issues-and-resolutions/ | |
module ActiveRecord::ConnectionAdapters | |
class MysqlAdapter | |
alias_method :execute_without_retry, :execute | |
def execute(*args) | |
execute_without_retry(*args) | |
rescue ActiveRecord::StatementInvalid => e | |
if e.message =~ /server has gone away/i | |
warn "Server timed out, retrying" | |
reconnect! | |
retry | |
else | |
raise e | |
end | |
end | |
end | |
end |
Oops -- that should have been:
Resque.after_fork do
ActiveRecord::Base.clear_active_connections!
end
For anyone running into this while forking in Rails, try clearing the existing connections before forking and then establish a new connection for each fork, like this:
# Clear existing connections before forking to ensure they do not get inherited.
::ActiveRecord::Base.clear_all_connections!
fork do
# Establish a new connection for each fork.
::ActiveRecord::Base.establish_connection
# The rest of the code for each fork...
end
See this StackOverflow answer here: https://stackoverflow.com/a/8915353/293280
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This should do the trick:
This would work both before & after forking the child, since it wouldn't close active connections, but it would check everything back in to the connection pool, and checking back out from the pool verifies the connections.