Class: Memcached

Inherits:
Object
  • Object
show all
Defined in:
lib/memcached/memcached.rb,
lib/memcached.rb,
lib/memcached/auth.rb,
lib/memcached/rails.rb,
lib/memcached/behaviors.rb,
lib/memcached/exceptions.rb

Overview

The Memcached client class.

Direct Known Subclasses

Rails

Defined Under Namespace

Classes: Error, Rails, Server

Constant Summary collapse

Lib = 
Rlibmemcached
VERSION = 
File.read("#{File.dirname(__FILE__)}/../CHANGELOG")[/v([\d\.]+)\./, 1]
BEHAVIORS = 
load_constants("MEMCACHED_BEHAVIOR_")
BEHAVIOR_VALUES = 
{
  false => 0, 
  true => 1
}
HASH_VALUES = 
{}
DISTRIBUTION_VALUES = 
{}
DIRECT_VALUE_BEHAVIORS = 
[:retry_timeout, :connect_timeout, :rcv_timeout, :socket_recv_size, :poll_timeout, :socket_send_size, :server_failure_limit]
CONVERSION_FACTORS = 
{
  :rcv_timeout => 1_000_000,
  :poll_timeout => 1_000,
  :connect_timeout => 1_000
}
FLAGS = 
0x0
DEFAULTS = 
{
  :hash => :fnv1_32,
  :no_block => false,
  :distribution => :consistent_ketama,
  :ketama_weighted => true,
  :buffer_requests => false,
  :cache_lookups => true,
  :support_cas => false,
  :tcp_nodelay => false,
  :show_backtraces => false,
  :retry_timeout => 30,
  :timeout => 0.25,
  :rcv_timeout => nil,
  :poll_timeout => nil,
  :connect_timeout => 4,
  :prefix_key => '',
  :prefix_delimiter => '',
  :hash_with_prefix_key => true,
  :default_ttl => 604800,
  :default_weight => 8,
  :sort_hosts => false,
  :auto_eject_hosts => true,
  :server_failure_limit => 2,
  :verify_key => true,
  :use_udp => false,
  :binary_protocol => false,
  :credentials => nil,
  :exception_retry_limit => 5,
  :exceptions_to_retry => [
      Memcached::ServerIsMarkedDead,
      Memcached::ATimeoutOccurred,
      Memcached::ConnectionBindFailure,
      Memcached::ConnectionFailure,
      Memcached::ConnectionSocketCreateFailure,
      Memcached::Failure,
      Memcached::MemoryAllocationFailure,
      Memcached::ReadFailure,
      Memcached::ServerError,
      Memcached::SystemError,
      Memcached::UnknownReadFailure,
      Memcached::WriteFailure]
}
IGNORED =

:stopdoc:

0
ERRNO_HASH = 


EXCEPTIONS =



[]


EMPTY_STRUCT =



Rlibmemcached::MemcachedSt.new




Instance Attribute Summary collapse




Class Method Summary
collapse





Instance Method Summary
collapse






Constructor Details





#initialize(servers = nil, opts = {}) ⇒ Memcached







Create a new Memcached instance. Accepts string or array of server strings, as well an an optional configuration hash.


Memcached.new('localhost', ...) # A single server
Memcached.new(['web001:11212', 'web002:11212'], ...) # Two servers with custom ports
Memcached.new(['web001:11211:2', 'web002:11211:8'], ...) # Two servers with default ports and explicit weights



Weights only affect Ketama hashing. If you use Ketama hashing and don’t specify a weight, the client will poll each server’s stats and use its size as the weight.


Valid option parameters are:


:prefix_key



A string to prepend to every key, for namespacing. Max length is 127. Defaults to the empty string.


:prefix_delimiter



A character to postpend to the prefix key. Defaults to the empty string.


:hash



The name of a hash function to use. Possible values are: :crc, :default, :fnv1_32, :fnv1_64, :fnv1a_32, :fnv1a_64, :hsieh, :md5, and :murmur. :fnv1_32 is fast and well known, and is the default. Use :md5 for compatibility with other ketama clients.


:distribution



Either :modula, :consistent_ketama, :consistent_wheel, or :ketama. Defaults to :ketama.


:server_failure_limit



How many consecutive failures to allow before marking a host as dead. Has no effect unless :retry_timeout is also set.


:retry_timeout



How long to wait until retrying a dead server. Has no effect unless :server_failure_limit is non-zero. Defaults to 30.


:auto_eject_hosts



Whether to temporarily eject dead hosts from the pool. Defaults to true. Note that in the event of an ejection, :auto_eject_hosts will remap the entire pool unless :distribution is set to :consistent.


:exception_retry_limit



How many times to retry before raising exceptions in :exceptions_to_retry. Defaults to 5.


:exceptions_to_retry



Which exceptions to retry. Defaults to ServerIsMarkedDead, ATimeoutOccurred, ConnectionBindFailure, ConnectionFailure, ConnectionSocketCreateFailure, Failure, MemoryAllocationFailure, ReadFailure, ServerError, SystemError, UnknownReadFailure, and WriteFailure.


:cache_lookups



Whether to cache hostname lookups for the life of the instance. Defaults to true.


:support_cas



Flag CAS support in the client. Accepts true or false. Defaults to false because it imposes a slight performance penalty. Note that your server must also support CAS or you will trigger ProtocolError exceptions.


:tcp_nodelay



Turns on the no-delay feature for connecting sockets. Accepts true or false. Performance may or may not change, depending on your system.


:no_block



Whether to use pipelining for writes. Accepts true or false.


:buffer_requests



Whether to use an internal write buffer. Accepts true or false. Calling get or closing the connection will force the buffer to flush. Note that :buffer_requests might not work well without :no_block also enabled.


:show_backtraces



Whether NotFound and NotStored exceptions should include backtraces. Generating backtraces is slow, so this is off by default. Turn it on to ease debugging.


:connect_timeout



How long to wait for a connection to a server. Defaults to 2 seconds. Set to 0 if you want to wait forever.


:timeout



How long to wait for a response from the server. Defaults to 0.25 seconds. Set to 0 if you want to wait forever.


:default_ttl



The ttl to use on set if no ttl is specified, in seconds. Defaults to one week. Set to 0 if you want things to never expire.


:default_weight



The weight to use if :ketama_weighted is true, but no weight is specified for a server.


:hash_with_prefix_key



Whether to include the prefix when calculating which server a key falls on. Defaults to true.


:use_udp



Use the UDP protocol to reduce connection overhead. Defaults to false.


:binary_protocol



Use the binary protocol to reduce query processing overhead. Defaults to false.


:sort_hosts



Whether to force the server list to stay sorted. This defeats consistent hashing and is rarely useful.


:verify_key



Validate keys before accepting them. Never disable this.




Please note that when :no_block => true, update methods do not raise on errors. For example, if you try to set an invalid key, it will appear to succeed. The actual setting of the key occurs after libmemcached has returned control to your program, so there is no way to backtrack and raise the exception.















99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158




# File 'lib/memcached/memcached.rb', line 99

def initialize(servers = nil, opts = {})
  @struct = Lib.memcached_create(nil)

  # Merge option defaults and discard meaningless keys
  @options = DEFAULTS.merge(opts)
  @options.delete_if { |k,v| not DEFAULTS.keys.include? k }
  @default_ttl = options[:default_ttl]

  if servers == nil || servers == []
    if ENV.key?("MEMCACHE_SERVERS")
      servers = ENV["MEMCACHE_SERVERS"].split(",").map do | s | s.strip end
    else
      servers = "127.0.0.1:11211"
    end
  end

  if options[:credentials] == nil && ENV.key?("MEMCACHE_USERNAME") && ENV.key?("MEMCACHE_PASSWORD")
    options[:credentials] = [ENV["MEMCACHE_USERNAME"], ENV["MEMCACHE_PASSWORD"]]
  end

  options[:binary_protocol] = true if options[:credentials] != nil

  # Force :buffer_requests to use :no_block
  # XXX Deleting the :no_block key should also work, but libmemcached doesn't seem to set it
  # consistently
  options[:no_block] = true if options[:buffer_requests]

  # Disallow weights without ketama
  options.delete(:ketama_weighted) if options[:distribution] != :consistent_ketama

  # Disallow :sort_hosts with consistent hashing
  if options[:sort_hosts] and options[:distribution] == :consistent
    raise ArgumentError, ":sort_hosts defeats :consistent hashing"
  end

  # Read timeouts
  options[:rcv_timeout] ||= options[:timeout] || 0
  options[:poll_timeout] ||= options[:timeout] || 0

  # Set the prefix key. Support the legacy name.
  set_prefix_key(options.delete(:prefix_key) || options.delete(:namespace))

  # Set the behaviors and credentials on the struct
  set_behaviors
  set_credentials

  # Freeze the hash
  options.freeze

  # Set the servers on the struct
  set_servers(servers)

  # Not found exceptions
  unless options[:show_backtraces]
    @not_found = NotFound.new
    @not_found.no_backtrace = true
    @not_stored = NotStored.new
    @not_stored.no_backtrace = true
  end
end













Instance Attribute Details






#options ⇒ Object (readonly)







:startdoc:















55
56
57




# File 'lib/memcached/memcached.rb', line 55

def options
  @options
end













Class Method Details





.load_constants(prefix, hash = {}) ⇒ Object







:stopdoc:















6
7
8
9
10
11




# File 'lib/memcached/behaviors.rb', line 6

def self.load_constants(prefix, hash = {})
  Lib.constants.grep(/^#{prefix}/).each do |const_name|
    hash[const_name[prefix.length..-1].downcase.to_sym] = Lib.const_get(const_name)
  end
  hash
end













Instance Method Details





#add(key, value, ttl = @default_ttl, marshal = true, flags = FLAGS) ⇒ Object







Add a key/value pair. Raises Memcached::NotStored if the key already exists on the server. The parameters are the same as set.















325
326
327
328
329
330
331
332
333
334
335
336
337
338




# File 'lib/memcached/memcached.rb', line 325

def add(key, value, ttl=@default_ttl, marshal=true, flags=FLAGS)
  value = marshal ? Marshal.dump(value) : value.to_s
  begin
    check_return_code(
      Lib.memcached_add(@struct, key, value, ttl, flags),
      key
    )
  rescue => e
    tries ||= 0
    raise unless tries < options[:exception_retry_limit] && should_retry(e)
    tries += 1
    retry 
  end
end












#append(key, value) ⇒ Object







Appends a string to a key’s value. Accepts a String key and a String value. Raises Memcached::NotFound if the key does not exist on the server.


Note that the key must be initialized to an unmarshalled string first, via set, add, or replace with marshal set to false.















392
393
394
395
396
397
398
399
400
401
402
403




# File 'lib/memcached/memcached.rb', line 392

def append(key, value)
  # Requires memcached 1.2.4
  check_return_code(
    Lib.memcached_append(@struct, key, value.to_s, IGNORED, IGNORED),
    key
  )
rescue => e
  tries ||= 0
  raise unless tries < options[:exception_retry_limit] && should_retry(e)
  tries += 1
  retry 
end












#cas(key, ttl = @default_ttl, marshal = true, flags = FLAGS) ⇒ Object
Also known as:
compare_and_swap








Reads a key’s value from the server and yields it to a block. Replaces the key’s value with the result of the block as long as the key hasn’t been updated in the meantime, otherwise raises Memcached::NotStored. Accepts a String key and a block.


Also accepts an optional ttl value.


CAS stands for “compare and swap”, and avoids the need for manual key mutexing. CAS support must be enabled in Memcached.new or a Memcached::ClientError will be raised. Note that CAS may be buggy in memcached itself. :retry_on_exceptions does not apply to this method








Raises:


    

  • 
(ClientError)

    • 










425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455




# File 'lib/memcached/memcached.rb', line 425

def cas(key, ttl=@default_ttl, marshal=true, flags=FLAGS)
  raise ClientError, "CAS not enabled for this Memcached instance" unless options[:support_cas]

  begin
    value, flags, ret = Lib.memcached_get_rvalue(@struct, key)
    check_return_code(ret, key)
  rescue => e
    tries_for_get ||= 0
    raise unless tries_for_get < options[:exception_retry_limit] && should_retry(e)
    tries_for_get += 1
    retry 
  end
  
  cas = @struct.result.cas

  value = Marshal.load(value) if marshal
  value = yield value
  value = Marshal.dump(value) if marshal

  begin
    check_return_code(
      Lib.memcached_cas(@struct, key, value, ttl, flags, cas),
      key
    )
  rescue => e
    tries_for_cas ||= 0
    raise unless tries_for_cas < options[:exception_retry_limit] && should_retry(e)
    tries_for_cas += 1
    retry 
  end
end












#clone ⇒ Object
Also known as:
dup








Safely copy this instance. Returns a Memcached instance.


clone is useful for threading, since each thread must have its own unshared Memcached object.















223
224
225
226
227
228
229
230




# File 'lib/memcached/memcached.rb', line 223

def clone
  # FIXME Memory leak
  # memcached = super
  # struct = Lib.memcached_clone(nil, @struct)
  # memcached.instance_variable_set('@struct', struct)
  # memcached
  self.class.new(servers, options.merge(:prefix_key => prefix_key))
end












#decrement(key, offset = 1) ⇒ Object
Also known as:
decr








Decrement a key’s value. The parameters and exception behavior are the same as increment.















357
358
359
360
361
362
363
364
365
366




# File 'lib/memcached/memcached.rb', line 357

def decrement(key, offset=1)
  ret, value = Lib.memcached_decrement(@struct, key, offset)
  check_return_code(ret, key)
  value
rescue => e
  tries ||= 0
  raise unless tries < options[:exception_retry_limit] && should_retry(e)
  tries += 1
  retry 
end












#delete(key) ⇒ Object







Deletes a key/value pair from the server. Accepts a String key. Raises Memcached::NotFound if the key does not exist.















462
463
464
465
466
467
468
469
470
471
472




# File 'lib/memcached/memcached.rb', line 462

def delete(key)
  check_return_code(
    Lib.memcached_delete(@struct, key, IGNORED),
    key
  )
rescue => e
  tries ||= 0
  raise unless tries < options[:exception_retry_limit] && should_retry(e)
  tries += 1
  retry 
end












#destroy_credentials ⇒ Object










2
3
4
5
6




# File 'lib/memcached/auth.rb', line 2

def destroy_credentials
  if options[:credentials] != nil
    check_return_code(Lib.memcached_destroy_sasl_auth_data(@struct))
  end
end












#flush ⇒ Object







Flushes all key/value pairs from all the servers.















475
476
477
478
479
480
481
482
483
484




# File 'lib/memcached/memcached.rb', line 475

def flush
  check_return_code(
    Lib.memcached_flush(@struct, IGNORED)
  )
rescue => e
  tries ||= 0
  raise unless tries < options[:exception_retry_limit] && should_retry(e)
  tries += 1
  retry 
end












#get(keys, marshal = true) ⇒ Object







Gets a key’s value from the server. Accepts a String key or array of String keys.


Also accepts a marshal value, which defaults to true. Set marshal to false if you want the value to be returned directly as a String. Otherwise it will be assumed to be a marshalled Ruby object and unmarshalled.


If you pass a String key, and the key does not exist on the server, Memcached::NotFound will be raised. If you pass an array of keys, memcached’s multiget mode will be used, and a hash of key/value pairs will be returned. The hash will contain only the keys that were found.


The multiget behavior is subject to change in the future; however, for multiple lookups, it is much faster than normal mode.


Note that when you rescue Memcached::NotFound exceptions, you should use a the block rescue syntax instead of the inline syntax. Block rescues are very fast, but inline rescues are very slow.















498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526




# File 'lib/memcached/memcached.rb', line 498

def get(keys, marshal=true)
  if keys.is_a? Array
    # Multi get
    ret = Lib.memcached_mget(@struct, keys);
    check_return_code(ret, keys)

    hash = {}
    keys.each do
      value, key, flags, ret = Lib.memcached_fetch_rvalue(@struct)
      break if ret == Lib::MEMCACHED_END
      if ret != Lib::MEMCACHED_NOTFOUND
        check_return_code(ret, key)
        # Assign the value
        hash[key] = (marshal ? Marshal.load(value) : value)
      end
    end
    hash
  else
    # Single get
    value, flags, ret = Lib.memcached_get_rvalue(@struct, keys)
    check_return_code(ret, keys)
    marshal ? Marshal.load(value) : value
  end
rescue => e
  tries ||= 0
  raise unless tries < options[:exception_retry_limit] && should_retry(e)
  tries += 1
  retry 
end












#increment(key, offset = 1) ⇒ Object
Also known as:
incr








Increment a key’s value. Accepts a String key. Raises Memcached::NotFound if the key does not exist.


Also accepts an optional offset paramater, which defaults to 1. offset must be an integer.


Note that the key must be initialized to an unmarshalled integer first, via set, add, or replace with marshal set to false.















345
346
347
348
349
350
351
352
353
354




# File 'lib/memcached/memcached.rb', line 345

def increment(key, offset=1)
  ret, value = Lib.memcached_increment(@struct, key, offset)
  check_return_code(ret, key)
  value
rescue => e
  tries ||= 0
  raise unless tries < options[:exception_retry_limit] && should_retry(e)
  tries += 1
  retry 
end












#prefix_key ⇒ Object
Also known as:
namespace








report the prefix_key















213
214
215




# File 'lib/memcached/memcached.rb', line 213

def prefix_key
  @struct.prefix_key[0..-1 - options[:prefix_delimiter].size] if @struct.prefix_key.size > 0
end












#prefix_key=(key) ⇒ Object
Also known as:
namespace=








change the prefix_key after we’re in motion















264
265
266
267
268
269
270
271




# File 'lib/memcached/memcached.rb', line 264

def prefix_key=(key)
  unless key.size < Lib::MEMCACHED_PREFIX_KEY_MAX_SIZE
    raise ArgumentError, "Max prefix_key size is #{Lib::MEMCACHED_PREFIX_KEY_MAX_SIZE - 1}"
  end
  check_return_code(
    Lib.memcached_callback_set(@struct, Lib::MEMCACHED_CALLBACK_PREFIX_KEY, "#{key}#{options[:prefix_delimiter]}")
  )
end












#prepend(key, value) ⇒ Object







Prepends a string to a key’s value. The parameters and exception behavior are the same as append.















406
407
408
409
410
411
412
413
414
415
416
417




# File 'lib/memcached/memcached.rb', line 406

def prepend(key, value)
  # Requires memcached 1.2.4
  check_return_code(
    Lib.memcached_prepend(@struct, key, value.to_s, IGNORED, IGNORED),
    key
  )
rescue => e
  tries ||= 0
  raise unless tries < options[:exception_retry_limit] && should_retry(e)
  tries += 1
  retry 
end












#quit ⇒ Object







Disconnect from all currently connected servers















248
249
250
251




# File 'lib/memcached/memcached.rb', line 248

def quit
  Lib.memcached_quit(@struct)
  self
end












#replace(key, value, ttl = @default_ttl, marshal = true, flags = FLAGS) ⇒ Object







Replace a key/value pair. Raises Memcached::NotFound if the key does not exist on the server. The parameters are the same as set.















374
375
376
377
378
379
380
381
382
383
384
385
386
387




# File 'lib/memcached/memcached.rb', line 374

def replace(key, value, ttl=@default_ttl, marshal=true, flags=FLAGS)
  value = marshal ? Marshal.dump(value) : value.to_s
  begin
    check_return_code(
       Lib.memcached_replace(@struct, key, value, ttl, flags),
      key
    )
  rescue => e
    tries ||= 0
    raise unless tries < options[:exception_retry_limit] && should_retry(e)
    tries += 1
    retry 
  end
end












#reset(current_servers = nil, with_prefix_key = true) ⇒ Object







Reset the state of the libmemcached struct. This is useful for changing the server list at runtime.















233
234
235
236
237
238
239
240
241
242
243
244
245




# File 'lib/memcached/memcached.rb', line 233

def reset(current_servers = nil, with_prefix_key = true)
  # Store state and teardown
  current_servers ||= servers
  prev_prefix_key = prefix_key

  # Create
  # FIXME Duplicates logic with initialize()
  @struct = Lib.memcached_create(nil)
  set_prefix_key(prev_prefix_key) if with_prefix_key
  set_behaviors
  set_credentials
  set_servers(current_servers)
end












#server_by_key(key) ⇒ Object







Return the server used by a particular key.















531
532
533
534
535
536
537
538
539




# File 'lib/memcached/memcached.rb', line 531

def server_by_key(key)
  ret = Lib.memcached_server_by_key(@struct, key)
  if ret.is_a?(Array)
    check_return_code(ret.last)
    inspect_server(ret.first)
  else
    check_return_code(ret)
  end
end












#servers ⇒ Object







Return the array of server strings used to configure this instance.















191
192
193
194
195




# File 'lib/memcached/memcached.rb', line 191

def servers
  server_structs.map do |server|
    inspect_server(server)
  end
end












#set(key, value, ttl = @default_ttl, marshal = true, flags = FLAGS) ⇒ Object







Set a key/value pair. Accepts a String key and an arbitrary Ruby object. Overwrites any existing value on the server.


Accepts an optional ttl value to specify the maximum lifetime of the key on the server. ttl can be either an integer number of seconds, or a Time elapsed time object. 0 means no ttl. Note that there is no guarantee that the key will persist as long as the ttl, but it will not persist longer.


Also accepts a marshal value, which defaults to true. Set marshal to false if you want the value to be set directly.















308
309
310
311
312
313
314
315
316
317
318
319
320
321
322




# File 'lib/memcached/memcached.rb', line 308

def set(key, value, ttl=@default_ttl, marshal=true, flags=FLAGS)
  value = marshal ? Marshal.dump(value) : value.to_s
  begin
    check_return_code(
      Lib.memcached_set(@struct, key, value, ttl, flags),
      key
    )
  rescue => e
    tries ||= 0
    retry if e.instance_of?(ClientError) && !tries
    raise unless tries < options[:exception_retry_limit] && should_retry(e)
    tries += 1
    retry 
  end
end












#set_prefix_key(key) ⇒ Object
Also known as:
set_namespace








Set the prefix key.















198
199
200
201
202
203
204
205
206
207
208
209




# File 'lib/memcached/memcached.rb', line 198

def set_prefix_key(key)
  check_return_code(
    if key
      key += options[:prefix_delimiter]
      raise ArgumentError, "Max prefix key + prefix delimiter size is #{Lib::MEMCACHED_PREFIX_KEY_MAX_SIZE - 1}" unless
        key.size < Lib::MEMCACHED_PREFIX_KEY_MAX_SIZE
      Lib.memcached_callback_set(@struct, Lib::MEMCACHED_CALLBACK_PREFIX_KEY, key)
    else
      Lib.memcached_callback_set(@struct, Lib::MEMCACHED_CALLBACK_PREFIX_KEY, "")
    end
  )
end












#set_servers(servers) ⇒ Object







Set the server list. FIXME Does not necessarily free any existing server structs.















162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188




# File 'lib/memcached/memcached.rb', line 162

def set_servers(servers)
  server_structs.each do |server|
    Lib.memcached_server_remove(server)
  end
  Array(servers).each_with_index do |server, index|
    # Socket
    check_return_code(
      if server.is_a?(String) and File.socket?(server)
        args = [@struct, server, options[:default_weight].to_i]
        Lib.memcached_server_add_unix_socket_with_weight(*args)
      # Network
      elsif server.is_a?(String) and server =~ /^[\w\d\.-]+(:\d{1,5}){0,2}$/
        host, port, weight = server.split(":")
        args = [@struct, host, port.to_i, (weight || options[:default_weight]).to_i]
        if options[:use_udp]
          Lib.memcached_server_add_udp_with_weight(*args)
        else
          Lib.memcached_server_add_with_weight(*args)
        end
      else
        raise ArgumentError, "Servers must be either in the format 'host:port[:weight]' (e.g., 'localhost:11211' or  'localhost:11211:10') for a network server, or a valid path to a Unix domain socket (e.g., /var/run/memcached)."
      end
    )
  end
  # For inspect
  @servers = send(:servers)
end












#should_retry(e) ⇒ Object







Should retry the exception















254
255
256
257




# File 'lib/memcached/memcached.rb', line 254

def should_retry(e)
  options[:exceptions_to_retry].each {|ex_class| return true if e.instance_of?(ex_class)}
  false
end












#stats(subcommand = nil) ⇒ Object







Return a Hash of statistics responses from the set of servers. Each value is an array with one entry for each server, in the same order the servers were defined.















542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576




# File 'lib/memcached/memcached.rb', line 542

def stats(subcommand = nil)
  stats = Hash.new([])

  stat_struct, ret = Lib.memcached_stat(@struct, subcommand)
  check_return_code(ret)

  keys, ret = Lib.memcached_stat_get_keys(@struct, stat_struct)
  check_return_code(ret)

  keys.each do |key|
     server_structs.size.times do |index|

       value, ret = Lib.memcached_stat_get_rvalue(
         @struct,
         Lib.memcached_select_stat_at(@struct, stat_struct, index),
         key)
       check_return_code(ret, key)

       value = case value
         when /^\d+\.\d+$/ then value.to_f
         when /^\d+$/ then value.to_i
         else value
       end

       stats[key.to_sym] += [value]
     end
  end

  Lib.memcached_stat_free(@struct, stat_struct)
  stats
rescue Memcached::SomeErrorsWereReported => _
  e = _.class.new("Error getting stats")
  e.set_backtrace(_.backtrace)
  raise e
end