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Fix the race condition caused by with_new_connections_blocked

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`with_new_connections_blocked` was introduced at #14938.
But the method sometimes causes `@new_cons_enabled = false` then never
toggled to true.
This commit is contained in:
Ryuta Kamizono 2016-11-16 05:24:45 +09:00
parent 3a558aa2bc
commit 700639e4f6
1 changed files with 4 additions and 8 deletions
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12
activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
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@ -350,8 +350,7 @@ module ActiveRecord
# currently in the process of independently establishing connections to the DB. # currently in the process of independently establishing connections to the DB.
@now_connecting = 0 @now_connecting = 0
# A boolean toggle that allows/disallows new connections. @new_cons_blocks = 0
@new_cons_enabled = true
@available = ConnectionLeasingQueue.new self @available = ConnectionLeasingQueue.new self
end end
@ -700,13 +699,10 @@ module ActiveRecord
end end
def with_new_connections_blocked def with_new_connections_blocked
previous_value = nil synchronize { @new_cons_blocks += 1 }
synchronize do
previous_value, @new_cons_enabled = @new_cons_enabled, false
end
yield yield
ensure ensure
synchronize { @new_cons_enabled = previous_value } synchronize { @new_cons_blocks -= 1 }
end end
# Acquire a connection by one of 1) immediately removing one # Acquire a connection by one of 1) immediately removing one
@ -758,7 +754,7 @@ module ActiveRecord
# and increment @now_connecting, to prevent overstepping this pool's @size # and increment @now_connecting, to prevent overstepping this pool's @size
# constraint # constraint
do_checkout = synchronize do do_checkout = synchronize do
if @new_cons_enabled && (@connections.size + @now_connecting) < @size if @new_cons_blocks.zero? && (@connections.size + @now_connecting) < @size
@now_connecting += 1 @now_connecting += 1
end end
end end