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Clear stale, cached connections left behind by defunct threads. Elimi…

…nate duplicate connection cache.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3729 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
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1 parent d8641ca commit 7568f18a2ac0813e0def5685bc272666b172a9dc @jeremy jeremy committed Mar 1, 2006
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@@ -1,5 +1,7 @@
*SVN*
+* Clear stale, cached connections left behind by defunct threads. [Jeremy Kemper]
+
* CHANGED DEFAULT: set ActiveRecord::Base.allow_concurrency to false. Most AR usage is in single-threaded applications. [Jeremy Kemper]
* Renamed the "oci" adapter to "oracle", but kept the old name as an alias #4017 [schoenm@earthlink.net]
@@ -1,3 +1,5 @@
+require 'set'
+
module ActiveRecord
class Base
class ConnectionSpecification #:nodoc:
@@ -7,70 +9,104 @@ def initialize (config, adapter_method)
end
end
- # Check connections for active? after +@@connection_cache_timeout+ seconds
- # defaults to 5 minutes
- cattr_accessor :connection_cache_timeout
- @@connection_cache_timeout = 300
-
+ # Check for activity after at least +verification_timeout+ seconds.
+ # Defaults to 0 (always check.)
+ cattr_accessor :verification_timeout
+ @@verification_timeout = 0
+
# The class -> [adapter_method, config] map
@@defined_connections = {}
# The class -> thread id -> adapter cache. (class -> adapter if not allow_concurrency)
- @@connection_cache = {}
+ @@active_connections = {}
- # retrieve the connection cache
- def self.connection_cache
- if @@allow_concurrency
- @@connection_cache[Thread.current.object_id] ||= {}
- else
- @@connection_cache
+ class << self
+ # Retrieve the connection cache.
+ def active_connections
+ if @@allow_concurrency
+ @@active_connections[Thread.current.object_id] ||= {}
+ else
+ @@active_connections
+ end
end
- end
-
- @connection_cache_key = nil
- def self.connection_cache_key
- @connection_cache_key ||=
- if active_connections[name] || @@defined_connections[name]
- name
- elsif self == ActiveRecord::Base
- nil
- else
- superclass.connection_cache_key
- end
- end
-
- def self.clear_connection_cache_key
- @connection_cache_key = nil
- subclasses.each{|klass| klass.clear_connection_cache_key }
- end
-
- # Returns the connection currently associated with the class. This can
- # also be used to "borrow" the connection to do database work unrelated
- # to any of the specific Active Records.
- def self.connection
- if (cache_key = @connection_cache_key) && (conn = connection_cache[cache_key])
- conn
- else
- conn = retrieve_connection # this will set @connection_cache_key
- connection_cache[@connection_cache_key] = conn
+
+ @active_connection_name = nil
+ def active_connection_name
+ @active_connection_name ||=
+ if active_connections[name] || @@defined_connections[name]
+ name
+ elsif self == ActiveRecord::Base
+ nil
+ else
+ superclass.active_connection_name
+ end
end
- end
- # Clears the cache which maps classes to connections.
- def self.clear_connection_cache!
- if @@allow_concurrency
- @@connection_cache.delete(Thread.current.object_id)
- else
- @@connection_cache = {}
+ def clear_active_connection_name
+ @active_connection_name = nil
+ subclasses.each { |klass| klass.clear_active_connection_name }
end
+
+ # Returns the connection currently associated with the class. This can
+ # also be used to "borrow" the connection to do database work unrelated
+ # to any of the specific Active Records.
+ def connection
+ if @active_connection_name && (conn = active_connections[@active_connection_name])
+ conn
+ else
+ # retrieve_connection sets the cache key.
+ active_connections[@active_connection_name] = retrieve_connection
+ end
+ end
+
+ # Clears the cache which maps classes to connections.
+ def clear_active_connections!
+ clear_cache!(@@active_connections)
+ end
+
+ # Verify active connections.
+ def verify_active_connections!
+ remove_stale_cached_threads!(@@active_connections) do |name, conn|
+ conn.disconnect!
+ end
+
+ active_connections.each_value do |connection|
+ connection.verify!(@@connection_cache_timeout)
+ end
+ end
+
+ private
+ def clear_cache!(cache, thread_id = nil, &block)
+ if cache
+ if @@allow_concurrency
+ thread_id ||= Thread.current.object_id
+ thread_cache, cache = cache, cache[thread_id]
+ return unless cache
+ end
+
+ cache.each(&block) if block_given?
+ cache.clear
+ end
+ ensure
+ if thread_cache && @@allow_concurrency
+ thread_cache.delete(thread_id)
+ end
+ end
+
+ # Remove stale threads from the cache.
+ def remove_stale_cached_threads!(cache, &block)
+ stale = Set.new(cache.keys)
+
+ Thread.list.each do |thread|
+ stale -= t.object_id if t.alive?
+ end
+
+ stale.each do |thread_id|
+ clear_cache!(cache, thread_id, &block)
+ end
+ end
end
-
- # Verify connection cache.
- def self.verify_connection_cache!
- timeout = @@connection_cache_timeout
- connection_cache.each_value { |connection| connection.verify!(timeout) }
- end
-
+
# Returns the connection currently associated with the class. This can
# also be used to "borrow" the connection to do database work that isn't
# easily done without going straight to SQL.
@@ -111,8 +147,8 @@ def self.establish_connection(spec = nil)
raise AdapterNotSpecified unless defined? RAILS_ENV
establish_connection(RAILS_ENV)
when ConnectionSpecification
- clear_connection_cache_key
- @connection_cache_key = name
+ clear_active_connection_name
+ @active_connection_name = name
@@defined_connections[name] = spec
when Symbol, String
if configuration = configurations[spec.to_s]
@@ -143,27 +179,26 @@ def self.active_connections #:nodoc:
# opened and set as the active connection for the class it was defined
# for (not necessarily the current class).
def self.retrieve_connection #:nodoc:
- cache_key = connection_cache_key
- # cache_key is nil if establish_connection hasn't been called for
- # some class along the inheritance chain up to AR::Base yet
- raise ConnectionNotEstablished unless cache_key
- if conn = active_connections[cache_key]
- # Verify the connection.
- conn.verify!(@@connection_cache_timeout)
- return conn
- elsif conn = @@defined_connections[cache_key]
- # Activate this connection specification.
- klass = cache_key.constantize
- klass.connection = conn
- return active_connections[cache_key]
- else
- raise ConnectionNotEstablished
+ # Name is nil if establish_connection hasn't been called for
+ # some class along the inheritance chain up to AR::Base yet.
+ if name = active_connection_name
+ if conn = active_connections[name]
+ # Verify the connection.
+ conn.verify!(@@verification_timeout)
+ elsif spec = @@defined_connections[name]
+ # Activate this connection specification.
+ klass = name.constantize
+ klass.connection = spec
+ conn = active_connections[name]
+ end
end
+
+ conn or raise ConnectionNotEstablished
end
# Returns true if a connection that's accessible to this class have already been opened.
def self.connected?
- active_connections[connection_cache_key] ? true : false
+ active_connections[active_connection_name] ? true : false
end
# Remove the connection for this class. This will close the active
@@ -174,7 +209,6 @@ def self.remove_connection(klass=self)
spec = @@defined_connections[klass.name]
konn = active_connections[klass.name]
@@defined_connections.delete_if { |key, value| value == spec }
- connection_cache.delete_if { |key, value| value == konn }
active_connections.delete_if { |key, value| value == konn }
konn.disconnect! if konn
spec.config if spec
@@ -192,14 +226,13 @@ def self.connection=(spec)
establish_connection spec
end
end
-
+
# connection state logging
def self.log_connections
if logger
logger.info "Defined connections: #{@@defined_connections.inspect}"
logger.info "Active connections: #{active_connections.inspect}"
- logger.info "Connection cache: #{connection_cache.inspect}"
- logger.info "Connection cache key: #{@connection_cache_key}"
+ logger.info "Active connection name: #{@active_connection_name}"
end
end
end
@@ -526,7 +526,7 @@ def teardown_with_fixtures
ActiveRecord::Base.connection.rollback_db_transaction
ActiveRecord::Base.unlock_mutex
end
- ActiveRecord::Base.clear_connection_cache!
+ ActiveRecord::Base.clear_active_connections!
end
alias_method :teardown, :teardown_with_fixtures

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