目次 †

↑

はじめに †

パフォーマンスが要求されるようなケースや大量のアクセスを捌く必要があるケースでは Lambda＆RDSはアンチパターン である事を認識しておく。
※コールドスタート時、VPC内に配置したLambda起動時にはENIアタッチが発生する為、Lambdaの起動に時間がかかる。
※インスタンスが持続して残る訳ではないので、コネクションプールがあまり意味を持たない為、結局はDBへの接続コストがかかる。
　（大量のアクセスを捌く場合は最大接続数も問題になる）

DB参考URL(同時接続数)
MySQLhttps://dev.mysql.com/doc/refman/5.6/ja/too-many-connections.html
AuroraMySQLhttps://docs.aws.amazon.com/ja_jp/AmazonRDS/latest/AuroraUserGuide/AuroraMySQL.Managing.Performance.html#AuroraMySQL.Managing.MaxConnections
↑

環境など †

・Lambda側のメモリは 128M、タイムアウトは1分に設定。
・EC2のインスタンスタイプは micro。
・リクエストは ローカル端末の Apache Bench で発行。
・Spring Boot 側のコネクションプール数は MAX:10、Initial:5 とした。
・計測前に何回かのリクエストを発行してウォームーアップを実施。（特に Lambda は Warm start できるように）
・それぞれの処理は テーブルから 数件のデータを読み出して返却するだけ。（Lambda側は3件、spring側は4件にした）

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結果(概要) †

以下、現時点(2017/10時点)の結果概要を記載する。

Aurora は MySQLベースらしいので、接続負荷もたいした事はないと踏んでいたが、やはりある程度は遅くなる事がわかった。

ただ、この結果を「全然使えない」と考えるか、「この程度であれば許容範囲」と考えるのかは要件しだいだと思う。
※DBがOracle だった場合、この程度の差ではすまない。

以下の記事で作成した Lambda関数と、コネクションプール有りの Spring Boot で検証した結果では 2〜4倍近く(※)の差が出たが、
ケースによってはもっと差が出るかもしれないし、出ないかもしれない。

↑

結果(詳細) †

特に Lambda は結果にバラつきが目立ったが、平均値で見ると Lambda と Spring Boot(EC2) では 約2-4倍の差が出た。

◆lambda に 10ユーザが1回ずつアクセス

Document Path:          /example/lambda-rds-access1
Document Length:        731 bytes

Concurrency Level:      10
Time taken for tests:   0.410 seconds
Complete requests:      10
Failed requests:        0
Total transferred:      11750 bytes
HTML transferred:       7310 bytes
Requests per second:    24.36 [#/sec] (mean)
Time per request:       410.499 [ms] (mean)
Time per request:       41.050 [ms] (mean, across all concurrent requests)
Transfer rate:          27.95 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:      144  163  18.1    169     190
Processing:    74  117  49.9    105     241
Waiting:       74  117  49.9    105     241
Total:        219  280  55.9    279     410

Percentage of the requests served within a certain time (ms)
  50%    279
  66%    296
  75%    297
  80%    319
  90%    410
  95%    410
  98%    410
  99%    410
 100%    410 (longest request)

◆spring に 10ユーザが1回ずつアクセス

Document Path:          /api/books
Document Length:        585 bytes

Concurrency Level:      10
Time taken for tests:   0.181 seconds
Complete requests:      10
Failed requests:        0
Total transferred:      7040 bytes
HTML transferred:       5850 bytes
Requests per second:    55.14 [#/sec] (mean)
Time per request:       181.346 [ms] (mean)
Time per request:       18.135 [ms] (mean, across all concurrent requests)
Transfer rate:          37.91 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:       93  102   3.4    103     104
Processing:    58   73   6.0     75      77
Waiting:       57   71   5.8     75      77
Total:        150  176   9.2    179     181

Percentage of the requests served within a certain time (ms)
  50%    179
  66%    179
  75%    181
  80%    181
  90%    181
  95%    181
  98%    181
  99%    181
 100%    181 (longest request)

◆lambda に 10ユーザが10回ずつアクセス

Document Path:          /example/lambda-rds-access1
Document Length:        569 bytes

Concurrency Level:      10
Time taken for tests:   3.743 seconds
Complete requests:      100
Failed requests:        0
Total transferred:      101300 bytes
HTML transferred:       56900 bytes
Requests per second:    26.72 [#/sec] (mean)
Time per request:       374.308 [ms] (mean)
Time per request:       37.431 [ms] (mean, across all concurrent requests)
Transfer rate:          26.43 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:      130  173  43.6    158     322
Processing:    71  185 117.1    149     563
Waiting:       71  185 117.1    148     563
Total:        224  359 154.7    312     839

Percentage of the requests served within a certain time (ms)
  50%    312
  66%    335
  75%    359
  80%    377
  90%    788
  95%    790
  98%    807
  99%    839
 100%    839 (longest request)

◆spring に 10ユーザが10回ずつアクセス

Document Path:          /api/books
Document Length:        585 bytes

Concurrency Level:      10
Time taken for tests:   1.324 seconds
Complete requests:      100
Failed requests:        0
Total transferred:      70400 bytes
HTML transferred:       58500 bytes
Requests per second:    75.54 [#/sec] (mean)
Time per request:       132.383 [ms] (mean)
Time per request:       13.238 [ms] (mean, across all concurrent requests)
Transfer rate:          51.93 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:       29   56  26.6     48     135
Processing:    38   70  18.7     68     112
Waiting:       37   68  18.1     67     105
Total:         79  126  38.3    116     241

Percentage of the requests served within a certain time (ms)
  50%    116
  66%    124
  75%    136
  80%    142
  90%    166
  95%    230
  98%    241
  99%    241
 100%    241 (longest request)

◆lambda に 100ユーザが10回ずつアクセス

Document Path:          /example/lambda-rds-access1
Document Length:        731 bytes

Concurrency Level:      100
Time taken for tests:   14.781 seconds
Complete requests:      1000
Failed requests:        0
Total transferred:      1175000 bytes
HTML transferred:       731000 bytes
Requests per second:    67.65 [#/sec] (mean)
Time per request:       1478.142 [ms] (mean)
Time per request:       14.781 [ms] (mean, across all concurrent requests)
Transfer rate:          77.63 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:      210  986 555.2    920    5907
Processing:    88  390 173.9    364    2383
Waiting:       87  380 171.0    357    2375
Total:        408 1376 585.8   1329    6320

Percentage of the requests served within a certain time (ms)
  50%   1329
  66%   1420
  75%   1461
  80%   1496
  90%   2000
  95%   2535
  98%   3300
  99%   3979
 100%   6320 (longest request)

◆spring に 100ユーザが10回ずつアクセス

Document Path:          /api/books
Document Length:        585 bytes

Concurrency Level:      100
Time taken for tests:   7.620 seconds
Complete requests:      1000
Failed requests:        0
Total transferred:      704000 bytes
HTML transferred:       585000 bytes
Requests per second:    131.24 [#/sec] (mean)
Time per request:       761.955 [ms] (mean)
Time per request:       7.620 [ms] (mean, across all concurrent requests)
Transfer rate:          90.23 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:       37  317  78.6    327     526
Processing:    86  395 213.3    353    1904
Waiting:       86  393 213.6    351    1902
Total:        127  712 233.3    690    2223

Percentage of the requests served within a certain time (ms)
  50%    690
  66%    729
  75%    753
  80%    761
  90%    805
  95%   1248
  98%   1518
  99%   1684
 100%   2223 (longest request)
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Last-modified: 2017-10-22 (日) 23:41:25 (3217d)