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Clear stale, cached connections left behind by defunct threads. Eliminate duplicate connection cache.

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git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3729 5ecf4fe2-1ee6-0310-87b1-e25e094e27de
This commit is contained in:
Jeremy Kemper
2006-03-01 22:05:41 +00:00
parent d8641ca34f
commit 7568f18a2a
3 changed files with 113 additions and 78 deletions
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2
activerecord/CHANGELOG
View File

@@ -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]

187
activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb
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@@ -1,3 +1,5 @@
require 'set'
module ActiveRecord
class Base
class ConnectionSpecification #:nodoc:
@@ -7,70 +9,104 @@ module ActiveRecord
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
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
# 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 = {}
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 @@ module ActiveRecord
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 @@ module ActiveRecord
# 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 @@ module ActiveRecord
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 @@ module ActiveRecord
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

2
activerecord/lib/active_record/fixtures.rb
View File

@@ -526,7 +526,7 @@ module Test #:nodoc:
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