Serverless彈效能力

PolarDB Serverless是基於“PolarDB Serverless: A Cloud Native Database for Disaggregated Data Centers”論文中所提出的成熟技術最終產品化結果。本文將使用Sysbench工具對PolarDB Serverless的彈效能力進行測試。您可以按照本文所述的方法自行進行測試，從而快速瞭解Serverless的彈效能力。

測試組態

ECS執行個體和PolarDB PostgreSQL版叢集位於同一地區，同一Virtual Private Cloud內。
PolarDB PostgreSQL版叢集配置如下：
- 叢集個數：1個
- 計費類型：Serverless
- 資料庫引擎：
- 產品版本：標準版
- 儲存類型及空間：ESSD AutoPL雲端硬碟（預置IOPS: 0），100 GB
說明
建立Serverless叢集時，規格中的唯讀節點個數的伸縮上下限以及單節點的伸縮上下限保持預設設定即可。
ECS執行個體配置如下：
- 執行個體個數：1台
- 執行個體規格：ecs.g7.4xlarge（16 vCPU 64 GiB）
- 鏡像：Alibaba Cloud Linux 3.2104 LTS 64位
- 系統硬碟：ESSD雲端硬碟，效能PL0，容量100 GB

測試載入器

Sysbench是一款開源的、跨平台的效能基準測試載入器，主要用於評估資料庫（例如PostgreSQL）的效能。該工具支援多線程測試，並提供靈活的配置選項。

準備工作

購買環境

根據測試組態，購買ECS執行個體及PolarDB PostgreSQL版Serverless叢集。

安裝Sysbench工具

使用root帳號登入ECS執行個體，安裝Sysbench工具。

sudo yum -y install sysbench

說明

此處以Alibaba Cloud Linux系統為例。若您使用的是其他動作系統，請按照Sysbench官方文檔調整相應的安裝命令。

配置叢集資訊

前往PolarDB控制台，建立資料庫帳號、建立資料庫並查看串連地址。

說明

ECS執行個體與PolarDB PostgreSQL版叢集處於同一Virtual Private Cloud內，請將ECS的私網IP地址添加至新的IP白名單分組，或將ECS所在的安全性群組添加至叢集白名單中。
串連地址請使用集群地址，而非主地址。

單節點縱向擴縮測試（Scale-up）

通過Sysbench工具驗證主節點的規格能夠根據負載自動進行伸縮。

資料準備

使用Sysbench工具在PolarDB PostgreSQL版叢集中準備32張表，每張表包含100,000行資料。執行過程中，可能會導致Serverless叢集規格的自動彈升。請在資料準備完成後，耐心等待3至5分鐘，直至主節點的規格降回1 PCU。資料準備命令如下，請根據實際情況調整相關參數：

sysbench /usr/share/sysbench/oltp_read_write.lua --pgsql-host=<host> --pgsql-port=<port> --pgsql-user=<user> --pgsql-password=<password> --pgsql-db=<database> --tables=32 --table-size=100000 --report-interval=1 --range_selects=1 --db-ps-mode=disable --rand-type=uniform --threads=32 --db-driver=pgsql --time=12000 prepare

Serverless叢集參數：
- <host>：叢集地址。
- <port>：叢集地址所對應的連接埠號碼，預設5432。
- <user>：資料庫帳號。
- <password>：資料庫帳號對應的密碼。
- <database>：資料庫名稱。
其他參數：
- --db-ps-mode：disable代表禁用先行編譯語句（Prepared Statements），以確保所有的事務SQL以原始SQL語句的方式執行。
- --threads：線程數。不同的線程數可以構造不同的負載。此處以32為例，表示在資料準備過程中使用32個線程，預計期間為5分鐘。

調整Serverless配置

在驗證單節點的擴縮測試過程中，需要確保壓力測試期間不會有隻讀節點彈升出來。請前往PolarDB控制台，在叢集詳情頁面的資料庫節點地區調整Serverless配置，將单节点资源弹升上限設定為32，单节点资源弹升下限設定為1，唯讀節點個數伸縮上下限設定為0。

初步驗證：低負載（16線程）

首先，進行一次簡單測試，評估16個線程的測試效果，從而對Serverless的彈效能力進行初步瞭解。

執行以下壓測命令。將--threads參數設定為16，其他參數請依據實際情況進行調整。

sysbench /usr/share/sysbench/oltp_read_write.lua --pgsql-host=<host> --pgsql-port=<port> --pgsql-user=<user> --pgsql-password=<password> --pgsql-db=<database> --tables=32 --table-size=100000 --report-interval=1 --range_selects=1 --db-ps-mode=disable --rand-type=uniform --threads=16 --db-driver=pgsql --time=12000 run

壓測結果如下。根據執行結果分析，在並發數量固定為16的負載條件下，隨著時間的推移，輸送量TPS逐步增加，而延遲LAT逐步降低，最終達到了一個穩定值。這表明在觸發Serverless彈性後，系統效能得到了明顯提升。

[   1s ] thds: 16 tps: 201.31 qps: 3221.01 (r/w/o: 2013.13/805.25/402.63) lat (ms,95%): 267.57 err/s: 0.00 reconn/s: 0.00
[   2s ] thds: 16 tps: 218.42 qps: 3494.74 (r/w/o: 2184.21/873.68/436.84) lat (ms,95%): 261.18 err/s: 0.00 reconn/s: 0.00
[   3s ] thds: 16 tps: 250.76 qps: 4012.10 (r/w/o: 2507.56/1003.02/501.51) lat (ms,95%): 255.63 err/s: 0.00 reconn/s: 0.00
[   4s ] thds: 16 tps: 283.90 qps: 4542.42 (r/w/o: 2839.01/1135.60/567.80) lat (ms,95%): 237.87 err/s: 0.00 reconn/s: 0.00
[   5s ] thds: 16 tps: 310.31 qps: 4965.02 (r/w/o: 3103.14/1241.25/620.63) lat (ms,95%): 223.91 err/s: 0.00 reconn/s: 0.00
[   6s ] thds: 16 tps: 344.22 qps: 5507.49 (r/w/o: 3442.18/1376.87/688.44) lat (ms,95%): 213.01 err/s: 0.00 reconn/s: 0.00
[   7s ] thds: 16 tps: 380.65 qps: 6090.34 (r/w/o: 3806.46/1522.58/761.29) lat (ms,95%): 194.05 err/s: 0.00 reconn/s: 0.00
[   8s ] thds: 16 tps: 439.63 qps: 7034.11 (r/w/o: 4396.32/1758.53/879.26) lat (ms,95%): 179.27 err/s: 0.00 reconn/s: 0.00
[   9s ] thds: 16 tps: 472.62 qps: 7561.95 (r/w/o: 4726.22/1890.49/945.24) lat (ms,95%): 161.66 err/s: 0.00 reconn/s: 0.00
[  10s ] thds: 16 tps: 535.06 qps: 8560.97 (r/w/o: 5350.61/2140.24/1070.12) lat (ms,95%): 140.52 err/s: 0.00 reconn/s: 0.00
[  11s ] thds: 16 tps: 578.67 qps: 9258.73 (r/w/o: 5786.71/2314.68/1157.34) lat (ms,95%): 127.29 err/s: 0.00 reconn/s: 0.00
[  12s ] thds: 16 tps: 602.52 qps: 9640.30 (r/w/o: 6025.19/2410.07/1205.04) lat (ms,95%): 108.84 err/s: 0.00 reconn/s: 0.00
[  13s ] thds: 16 tps: 662.48 qps: 10599.62 (r/w/o: 6624.76/2649.90/1324.95) lat (ms,95%): 95.25 err/s: 0.00 reconn/s: 0.00
[  14s ] thds: 16 tps: 660.53 qps: 10568.41 (r/w/o: 6605.26/2642.10/1321.05) lat (ms,95%): 81.71 err/s: 0.00 reconn/s: 0.00
[  15s ] thds: 16 tps: 719.74 qps: 11515.81 (r/w/o: 7197.38/2878.95/1439.48) lat (ms,95%): 72.24 err/s: 0.00 reconn/s: 0.00
[  16s ] thds: 16 tps: 742.23 qps: 11875.72 (r/w/o: 7422.32/2968.93/1484.46) lat (ms,95%): 63.07 err/s: 0.00 reconn/s: 0.00
[  17s ] thds: 16 tps: 750.29 qps: 12004.67 (r/w/o: 7502.92/3001.17/1500.58) lat (ms,95%): 55.64 err/s: 0.00 reconn/s: 0.00
[  18s ] thds: 16 tps: 759.46 qps: 12151.38 (r/w/o: 7594.61/3037.84/1518.92) lat (ms,95%): 48.20 err/s: 0.00 reconn/s: 0.00
[  19s ] thds: 16 tps: 793.76 qps: 12700.22 (r/w/o: 7937.64/3175.06/1587.53) lat (ms,95%): 43.00 err/s: 0.00 reconn/s: 0.00
[  20s ] thds: 16 tps: 806.28 qps: 12900.48 (r/w/o: 8062.80/3225.12/1612.56) lat (ms,95%): 38.63 err/s: 0.00 reconn/s: 0.00
[  21s ] thds: 16 tps: 807.58 qps: 12921.27 (r/w/o: 8075.79/3230.32/1615.16) lat (ms,95%): 34.45 err/s: 0.00 reconn/s: 0.00
[  22s ] thds: 16 tps: 791.53 qps: 12664.44 (r/w/o: 7915.27/3166.11/1583.05) lat (ms,95%): 32.08 err/s: 0.00 reconn/s: 0.00
[  23s ] thds: 16 tps: 789.69 qps: 12635.06 (r/w/o: 7896.91/3158.76/1579.38) lat (ms,95%): 29.86 err/s: 0.00 reconn/s: 0.00
[  24s ] thds: 16 tps: 794.92 qps: 12718.79 (r/w/o: 7949.24/3179.70/1589.85) lat (ms,95%): 28.22 err/s: 0.00 reconn/s: 0.00
[  25s ] thds: 16 tps: 824.47 qps: 13191.51 (r/w/o: 8244.69/3297.88/1648.94) lat (ms,95%): 26.98 err/s: 0.00 reconn/s: 0.00

返回PolarDB控制台，在效能監控頁面查看Serverless监控指标项。時間範圍選擇最近的5分鐘，可以看到如下監控資訊：

PCU數量由1彈升至4並保持穩定。在彈升過程中，CPU的使用率隨著資源的擴容而逐步降低。記憶體使用量率曲線在每次彈升時呈現脈衝形狀。這是由於每次PCU增加時，記憶體資源會進行擴容，此時的記憶體使用量率會瞬時下降。隨後，資料庫開始利用擴充的記憶體資源提升計算能力（例如Shared Buffer），因此記憶體使用量率會逐步增加，最終達到一個穩定點。
停止壓測命令，稍等5分鐘。隨後，調整時間範圍至最近的10分鐘，可以查看到以下監控資訊：

隨著壓力的停止，PCU數量從4逐步階梯式地降低至1。由於讀寫混合測試中包含UPDATE請求，當壓力停止後，PolarDB仍會繼續執行vacuum 操作，因此會佔用少量的CPU資源。

深入驗證：高負載（128線程）

接下來，將線程數（--threads參數）設定為128，查看PolarDB Serverless叢集彈升至最大規格32 PCU所需的時間。在進行壓測一段時間後，停止測試。

執行以下壓測命令。將--threads參數設定為128，其他參數請依據實際情況進行調整。具體資訊，請參見參數說明。

sysbench /usr/share/sysbench/oltp_read_write.lua --pgsql-host=<host> --pgsql-port=<port> --pgsql-user=<user> --pgsql-password=<password> --pgsql-db=<database> --tables=32 --table-size=100000 --report-interval=1 --range_selects=1 --db-ps-mode=disable --rand-type=uniform --threads=128 --db-driver=pgsql --time=12000 run

壓測結果：根據執行結果，可以明顯看出來輸送量TPS和延遲LAT的變化。

[   1s ] thds: 128 tps: 499.33 qps: 7989.27 (r/w/o: 4993.30/1997.32/998.66) lat (ms,95%): 299.20 err/s: 0.00 reconn/s: 0.00
[   2s ] thds: 128 tps: 506.53 qps: 8104.48 (r/w/o: 5065.30/2026.12/1013.06) lat (ms,95%): 307.36 err/s: 0.00 reconn/s: 0.00
[   3s ] thds: 128 tps: 529.89 qps: 8478.18 (r/w/o: 5298.86/2119.54/1059.77) lat (ms,95%): 302.71 err/s: 0.00 reconn/s: 0.00
[   4s ] thds: 128 tps: 527.26 qps: 8436.16 (r/w/o: 5272.60/2109.04/1054.52) lat (ms,95%): 303.39 err/s: 0.00 reconn/s: 0.00
[   5s ] thds: 128 tps: 540.63 qps: 8650.11 (r/w/o: 5406.32/2162.53/1081.26) lat (ms,95%): 298.35 err/s: 0.00 reconn/s: 0.00
[   6s ] thds: 128 tps: 583.70 qps: 9339.16 (r/w/o: 5836.97/2334.79/1167.39) lat (ms,95%): 300.56 err/s: 0.00 reconn/s: 0.00
[   7s ] thds: 128 tps: 585.79 qps: 9372.66 (r/w/o: 5857.92/2343.17/1171.58) lat (ms,95%): 300.08 err/s: 0.00 reconn/s: 0.00
[   8s ] thds: 128 tps: 614.56 qps: 9832.92 (r/w/o: 6145.58/2458.23/1229.12) lat (ms,95%): 300.05 err/s: 0.00 reconn/s: 0.00
[   9s ] thds: 128 tps: 612.19 qps: 9795.00 (r/w/o: 6121.88/2448.75/1224.38) lat (ms,95%): 290.03 err/s: 0.00 reconn/s: 0.00
[  10s ] thds: 128 tps: 637.21 qps: 10195.42 (r/w/o: 6372.14/2548.86/1274.43) lat (ms,95%): 291.50 err/s: 0.00 reconn/s: 0.00
[  11s ] thds: 128 tps: 656.87 qps: 10509.92 (r/w/o: 6568.70/2627.48/1313.74) lat (ms,95%): 297.98 err/s: 0.00 reconn/s: 0.00
[  12s ] thds: 128 tps: 710.50 qps: 11368.01 (r/w/o: 7105.01/2842.00/1421.00) lat (ms,95%): 289.05 err/s: 0.00 reconn/s: 0.00
[  13s ] thds: 128 tps: 730.32 qps: 11685.11 (r/w/o: 7303.19/2921.28/1460.64) lat (ms,95%): 288.27 err/s: 0.00 reconn/s: 0.00
[  14s ] thds: 128 tps: 773.70 qps: 12379.23 (r/w/o: 7737.02/3094.81/1547.40) lat (ms,95%): 287.12 err/s: 0.00 reconn/s: 0.00
[  15s ] thds: 128 tps: 777.93 qps: 12446.87 (r/w/o: 7779.30/3111.72/1555.86) lat (ms,95%): 282.65 err/s: 0.00 reconn/s: 0.00
[  16s ] thds: 128 tps: 829.21 qps: 13267.43 (r/w/o: 8292.15/3316.86/1658.43) lat (ms,95%): 280.62 err/s: 0.00 reconn/s: 0.00
[  17s ] thds: 128 tps: 870.85 qps: 13933.65 (r/w/o: 8708.53/3483.41/1741.71) lat (ms,95%): 285.36 err/s: 0.00 reconn/s: 0.00
[  18s ] thds: 128 tps: 904.61 qps: 14473.81 (r/w/o: 9046.13/3618.45/1809.23) lat (ms,95%): 275.14 err/s: 0.00 reconn/s: 0.00
[  19s ] thds: 128 tps: 985.90 qps: 15774.36 (r/w/o: 9858.98/3943.59/1971.80) lat (ms,95%): 275.53 err/s: 0.00 reconn/s: 0.00
[  20s ] thds: 128 tps: 983.53 qps: 15736.55 (r/w/o: 9835.35/3934.14/1967.07) lat (ms,95%): 267.43 err/s: 0.00 reconn/s: 0.00
[  21s ] thds: 128 tps: 1038.28 qps: 16612.42 (r/w/o: 10382.76/4153.11/2076.55) lat (ms,95%): 270.44 err/s: 0.00 reconn/s: 0.00
[  22s ] thds: 128 tps: 1141.83 qps: 18269.33 (r/w/o: 11418.33/4567.33/2283.67) lat (ms,95%): 264.70 err/s: 0.00 reconn/s: 0.00
[  23s ] thds: 128 tps: 1154.36 qps: 18469.71 (r/w/o: 11543.57/4617.43/2308.71) lat (ms,95%): 260.48 err/s: 0.00 reconn/s: 0.00
[  24s ] thds: 128 tps: 1290.30 qps: 20644.80 (r/w/o: 12903.00/5161.20/2580.60) lat (ms,95%): 257.96 err/s: 0.00 reconn/s: 0.00
[  25s ] thds: 128 tps: 1362.52 qps: 21800.29 (r/w/o: 13625.18/5450.07/2725.04) lat (ms,95%): 256.99 err/s: 0.00 reconn/s: 0.00
[  26s ] thds: 128 tps: 1360.57 qps: 21769.10 (r/w/o: 13605.69/5442.28/2721.14) lat (ms,95%): 250.92 err/s: 0.00 reconn/s: 0.00
[  27s ] thds: 128 tps: 1498.95 qps: 23983.21 (r/w/o: 14989.51/5995.80/2997.90) lat (ms,95%): 244.21 err/s: 0.00 reconn/s: 0.00
[  28s ] thds: 128 tps: 1546.49 qps: 24743.87 (r/w/o: 15464.92/6185.97/3092.98) lat (ms,95%): 240.05 err/s: 0.00 reconn/s: 0.00
[  29s ] thds: 128 tps: 1619.87 qps: 25917.98 (r/w/o: 16198.74/6479.50/3239.75) lat (ms,95%): 232.68 err/s: 0.00 reconn/s: 0.00
[  30s ] thds: 128 tps: 1748.07 qps: 27969.11 (r/w/o: 17480.70/6992.28/3496.14) lat (ms,95%): 231.75 err/s: 0.00 reconn/s: 0.00
[  31s ] thds: 128 tps: 1893.22 qps: 30291.57 (r/w/o: 18932.23/7572.89/3786.45) lat (ms,95%): 219.60 err/s: 0.00 reconn/s: 0.00
[  32s ] thds: 128 tps: 1953.95 qps: 31263.22 (r/w/o: 19539.51/7815.81/3907.90) lat (ms,95%): 212.77 err/s: 0.00 reconn/s: 0.00
[  33s ] thds: 128 tps: 2110.86 qps: 33773.82 (r/w/o: 21108.64/8443.45/4221.73) lat (ms,95%): 212.28 err/s: 0.00 reconn/s: 0.00
[  34s ] thds: 128 tps: 2142.82 qps: 34285.18 (r/w/o: 21428.24/8571.29/4285.65) lat (ms,95%): 203.74 err/s: 0.00 reconn/s: 0.00
[  35s ] thds: 128 tps: 2295.94 qps: 36735.05 (r/w/o: 22959.41/9183.76/4591.88) lat (ms,95%): 193.17 err/s: 0.00 reconn/s: 0.00
[  36s ] thds: 128 tps: 2433.04 qps: 38928.63 (r/w/o: 24330.39/9732.16/4866.08) lat (ms,95%): 189.32 err/s: 0.00 reconn/s: 0.00
[  37s ] thds: 128 tps: 2553.38 qps: 40854.06 (r/w/o: 25533.79/10213.51/5106.76) lat (ms,95%): 182.26 err/s: 0.00 reconn/s: 0.00
[  38s ] thds: 128 tps: 2549.95 qps: 40799.26 (r/w/o: 25499.54/10199.82/5099.91) lat (ms,95%): 173.76 err/s: 0.00 reconn/s: 0.00
[  39s ] thds: 128 tps: 2667.54 qps: 42680.64 (r/w/o: 26675.40/10670.16/5335.08) lat (ms,95%): 170.78 err/s: 0.00 reconn/s: 0.00
[  40s ] thds: 128 tps: 2929.93 qps: 46878.81 (r/w/o: 29299.25/11719.70/5859.85) lat (ms,95%): 162.94 err/s: 0.00 reconn/s: 0.00
[  41s ] thds: 128 tps: 2947.98 qps: 47167.64 (r/w/o: 29479.77/11791.91/5895.95) lat (ms,95%): 151.02 err/s: 0.00 reconn/s: 0.00
[  42s ] thds: 128 tps: 3169.22 qps: 50707.58 (r/w/o: 31692.24/12676.89/6338.45) lat (ms,95%): 149.36 err/s: 0.00 reconn/s: 0.00
[  43s ] thds: 128 tps: 3133.92 qps: 50142.71 (r/w/o: 31339.20/12535.68/6267.84) lat (ms,95%): 139.75 err/s: 0.00 reconn/s: 0.00
[  44s ] thds: 128 tps: 3240.55 qps: 51848.86 (r/w/o: 32405.54/12962.21/6481.11) lat (ms,95%): 134.45 err/s: 0.00 reconn/s: 0.00
[  45s ] thds: 128 tps: 3491.42 qps: 55862.72 (r/w/o: 34914.20/13965.68/6982.84) lat (ms,95%): 124.56 err/s: 0.00 reconn/s: 0.00
[  46s ] thds: 128 tps: 3538.34 qps: 56613.38 (r/w/o: 35383.36/14153.35/7076.67) lat (ms,95%): 120.25 err/s: 0.00 reconn/s: 0.00
[  47s ] thds: 128 tps: 3595.70 qps: 57531.17 (r/w/o: 35956.98/14382.79/7191.40) lat (ms,95%): 115.49 err/s: 0.00 reconn/s: 0.00
[  48s ] thds: 128 tps: 3729.56 qps: 59672.91 (r/w/o: 37295.57/14918.23/7459.11) lat (ms,95%): 106.56 err/s: 0.00 reconn/s: 0.00
[  49s ] thds: 128 tps: 3851.56 qps: 61625.02 (r/w/o: 38515.64/15406.26/7703.13) lat (ms,95%): 102.99 err/s: 0.00 reconn/s: 0.00
[  50s ] thds: 128 tps: 3863.37 qps: 61813.92 (r/w/o: 38633.70/15453.48/7726.74) lat (ms,95%): 95.83 err/s: 0.00 reconn/s: 0.00
[  51s ] thds: 128 tps: 4140.36 qps: 66245.75 (r/w/o: 41403.59/16561.44/8280.72) lat (ms,95%): 91.88 err/s: 0.00 reconn/s: 0.00
[  52s ] thds: 128 tps: 4088.15 qps: 65410.47 (r/w/o: 40881.54/16352.62/8176.31) lat (ms,95%): 86.44 err/s: 0.00 reconn/s: 0.00
[  53s ] thds: 128 tps: 4086.26 qps: 65380.19 (r/w/o: 40862.62/16345.05/8172.52) lat (ms,95%): 80.79 err/s: 0.00 reconn/s: 0.00
[  54s ] thds: 128 tps: 4213.43 qps: 67414.83 (r/w/o: 42134.27/16853.71/8426.85) lat (ms,95%): 77.55 err/s: 0.00 reconn/s: 0.00
[  55s ] thds: 128 tps: 4253.68 qps: 68058.86 (r/w/o: 42536.78/17014.71/8507.36) lat (ms,95%): 72.32 err/s: 0.00 reconn/s: 0.00
[  56s ] thds: 128 tps: 4275.27 qps: 68404.32 (r/w/o: 42752.70/17101.08/8550.54) lat (ms,95%): 69.62 err/s: 0.00 reconn/s: 0.00
[  57s ] thds: 128 tps: 4376.13 qps: 70018.00 (r/w/o: 43761.25/17504.50/8752.25) lat (ms,95%): 66.70 err/s: 0.00 reconn/s: 0.00
[  58s ] thds: 128 tps: 4601.78 qps: 73628.47 (r/w/o: 46017.79/18407.12/9203.56) lat (ms,95%): 61.20 err/s: 0.00 reconn/s: 0.00
[  59s ] thds: 128 tps: 4485.07 qps: 71761.18 (r/w/o: 44850.73/17940.29/8970.15) lat (ms,95%): 59.53 err/s: 0.00 reconn/s: 0.00
[  60s ] thds: 128 tps: 4526.07 qps: 72417.05 (r/w/o: 45260.66/18104.26/9052.13) lat (ms,95%): 55.40 err/s: 0.00 reconn/s: 0.00
[  61s ] thds: 128 tps: 4771.22 qps: 76339.57 (r/w/o: 47712.23/19084.89/9542.45) lat (ms,95%): 53.70 err/s: 0.00 reconn/s: 0.00
[  62s ] thds: 128 tps: 4683.30 qps: 74932.84 (r/w/o: 46833.02/18733.21/9366.60) lat (ms,95%): 51.65 err/s: 0.00 reconn/s: 0.00
[  63s ] thds: 128 tps: 4816.29 qps: 77060.59 (r/w/o: 48162.87/19265.15/9632.57) lat (ms,95%): 48.17 err/s: 0.00 reconn/s: 0.00
[  64s ] thds: 128 tps: 4648.83 qps: 74381.29 (r/w/o: 46488.31/18595.32/9297.66) lat (ms,95%): 46.55 err/s: 0.00 reconn/s: 0.00
[  65s ] thds: 128 tps: 4774.22 qps: 76387.55 (r/w/o: 47742.22/19096.89/9548.44) lat (ms,95%): 44.68 err/s: 0.00 reconn/s: 0.00
[  66s ] thds: 128 tps: 4892.06 qps: 78272.96 (r/w/o: 48920.60/19568.24/9784.12) lat (ms,95%): 43.27 err/s: 0.00 reconn/s: 0.00
[  67s ] thds: 128 tps: 4993.76 qps: 79900.15 (r/w/o: 49937.59/19975.04/9987.52) lat (ms,95%): 40.68 err/s: 0.00 reconn/s: 0.00
[  68s ] thds: 128 tps: 4849.05 qps: 77584.86 (r/w/o: 48490.54/19396.22/9698.11) lat (ms,95%): 39.60 err/s: 0.00 reconn/s: 0.00
[  69s ] thds: 128 tps: 5006.54 qps: 80104.57 (r/w/o: 50065.36/20026.14/10013.07) lat (ms,95%): 38.11 err/s: 0.00 reconn/s: 0.00
[  70s ] thds: 128 tps: 4829.42 qps: 77270.78 (r/w/o: 48294.24/19317.70/9658.85) lat (ms,95%): 37.17 err/s: 0.00 reconn/s: 0.00
[  71s ] thds: 128 tps: 4916.62 qps: 78665.99 (r/w/o: 49166.24/19666.50/9833.25) lat (ms,95%): 35.79 err/s: 0.00 reconn/s: 0.00
[  72s ] thds: 128 tps: 4882.59 qps: 78121.45 (r/w/o: 48825.91/19530.36/9765.18) lat (ms,95%): 35.67 err/s: 0.00 reconn/s: 0.00
[  73s ] thds: 128 tps: 4955.74 qps: 79291.77 (r/w/o: 49557.35/19822.94/9911.47) lat (ms,95%): 34.63 err/s: 0.00 reconn/s: 0.00
[  74s ] thds: 128 tps: 5002.06 qps: 80032.97 (r/w/o: 50020.61/20008.24/10004.12) lat (ms,95%): 32.68 err/s: 0.00 reconn/s: 0.00
[  75s ] thds: 128 tps: 5149.80 qps: 82396.85 (r/w/o: 51498.03/20599.21/10299.61) lat (ms,95%): 32.93 err/s: 0.00 reconn/s: 0.00
[  76s ] thds: 128 tps: 5152.89 qps: 82446.27 (r/w/o: 51528.92/20611.57/10305.78) lat (ms,95%): 32.33 err/s: 0.00 reconn/s: 0.00
[  77s ] thds: 128 tps: 5127.71 qps: 82043.33 (r/w/o: 51277.08/20510.83/10255.42) lat (ms,95%): 30.72 err/s: 0.00 reconn/s: 0.00
[  78s ] thds: 128 tps: 5028.08 qps: 80449.22 (r/w/o: 50280.76/20112.30/10056.15) lat (ms,95%): 30.20 err/s: 0.00 reconn/s: 0.00
[  79s ] thds: 128 tps: 5011.37 qps: 80181.90 (r/w/o: 50113.69/20045.47/10022.74) lat (ms,95%): 29.48 err/s: 0.00 reconn/s: 0.00
[  80s ] thds: 128 tps: 5012.71 qps: 80203.34 (r/w/o: 50127.09/20050.84/10025.42) lat (ms,95%): 30.10 err/s: 0.00 reconn/s: 0.00
[  81s ] thds: 128 tps: 4985.47 qps: 79767.47 (r/w/o: 49854.67/19941.87/9970.93) lat (ms,95%): 29.42 err/s: 0.00 reconn/s: 0.00
[  82s ] thds: 128 tps: 5049.69 qps: 80795.02 (r/w/o: 50496.89/20198.75/10099.38) lat (ms,95%): 28.60 err/s: 0.00 reconn/s: 0.00
[  83s ] thds: 128 tps: 5208.49 qps: 83335.87 (r/w/o: 52084.92/20833.97/10416.98) lat (ms,95%): 28.89 err/s: 0.00 reconn/s: 0.00
[  84s ] thds: 128 tps: 5091.85 qps: 81469.57 (r/w/o: 50918.48/20367.39/10183.70) lat (ms,95%): 28.24 err/s: 0.00 reconn/s: 0.00
[  85s ] thds: 128 tps: 4974.62 qps: 79593.88 (r/w/o: 49746.17/19898.47/9949.23) lat (ms,95%): 27.47 err/s: 0.00 reconn/s: 0.00
[  86s ] thds: 128 tps: 5227.32 qps: 83637.08 (r/w/o: 52273.18/20909.27/10454.64) lat (ms,95%): 27.52 err/s: 0.00 reconn/s: 0.00
[  87s ] thds: 128 tps: 5101.30 qps: 81620.74 (r/w/o: 51012.96/20405.18/10202.59) lat (ms,95%): 27.45 err/s: 0.00 reconn/s: 0.00

前往PolarDB控制台，在效能監控頁面查看Serverless监控指标项。根據測試時間調整時間範圍，可以看到如下監控資訊：

從1 PCU彈升至32 PCU耗時大約需要87秒。縮容相比擴容稍顯平緩，耗時大約231秒。

多節點橫向擴縮測試（Scale-out）

通過Sysbench工具驗證叢集唯讀節點數量根據負載自動進行伸縮。

調整Serverless配置

在驗證多節點的擴縮測試過程中，需要確保壓力測試期間會有隻讀節點自動彈升出來。請前往PolarDB控制台，在叢集詳情頁面的資料庫節點地區調整Serverless配置。將单节点资源弹升上限設定為32，单节点资源弹升下限設定為1，只读节点个数伸缩上限設定為7，只读节点个数伸缩下限設定為0。

驗證

進行160個線程的測試，瞭解Serverless的橫向彈效能力。

執行以下壓測命令。將--threads參數設定為160，其他參數請依據實際情況進行調整。具體資訊，請參見參數說明。

sysbench /usr/share/sysbench/oltp_read_write.lua --pgsql-host=<host> --pgsql-port=<port> --pgsql-user=<user> --pgsql-password=<password> --pgsql-db=<database> --tables=32 --table-size=100000 --report-interval=1 --range_selects=1 --db-ps-mode=disable --rand-type=uniform --threads=160 --db-driver=pgsql --time=12000 run

等待一段時間後，系統將開始彈出新的唯讀節點。

此時資料庫節點地區將顯示新增的唯讀節點，狀態為運行中，規格為1~32 PCU。

進入穩定點後，壓測結果如下。與之前單節點同壓力的測試結果相比，QPS從32萬上升到34萬。根據QPS的表現，已突破單節點彈性測試的最大輸送量。

[ 131s ] thds: 128 tps: 16823.87 qps: 269181.86 (r/w/o: 168238.66/67295.46/33647.73) lat (ms,95%): 13.51 err/s: 0.00 reconn/s: 0.00
[ 132s ] thds: 128 tps: 17002.14 qps: 272034.24 (r/w/o: 170021.40/68008.56/34004.28) lat (ms,95%): 13.67 err/s: 0.00 reconn/s: 0.00
[ 133s ] thds: 128 tps: 16863.97 qps: 269823.57 (r/w/o: 168639.73/67455.89/33727.95) lat (ms,95%): 13.74 err/s: 0.00 reconn/s: 0.00
[ 134s ] thds: 128 tps: 16833.04 qps: 269328.71 (r/w/o: 168330.45/67332.18/33666.09) lat (ms,95%): 13.27 err/s: 0.00 reconn/s: 0.00
[ 135s ] thds: 128 tps: 17039.01 qps: 272624.22 (r/w/o: 170390.14/68156.06/34078.03) lat (ms,95%): 13.57 err/s: 0.00 reconn/s: 0.00
[ 136s ] thds: 128 tps: 16895.08 qps: 270321.30 (r/w/o: 168950.82/67580.33/33790.16) lat (ms,95%): 13.23 err/s: 0.00 reconn/s: 0.00
[ 137s ] thds: 128 tps: 17157.11 qps: 274513.84 (r/w/o: 171571.15/68628.46/34314.23) lat (ms,95%): 13.31 err/s: 0.00 reconn/s: 0.00
[ 138s ] thds: 128 tps: 17038.81 qps: 272620.92 (r/w/o: 170388.08/68155.23/34077.62) lat (ms,95%): 13.53 err/s: 0.00 reconn/s: 0.00
[ 139s ] thds: 128 tps: 16968.69 qps: 271499.04 (r/w/o: 169686.90/67874.76/33937.38) lat (ms,95%): 13.51 err/s: 0.00 reconn/s: 0.00
[ 140s ] thds: 128 tps: 17010.11 qps: 272161.81 (r/w/o: 170101.13/68040.45/34020.23) lat (ms,95%): 13.72 err/s: 0.00 reconn/s: 0.00

橫向彈升，基準對照，單節點：

[   1s ] thds: 160 tps: 737.10 qps: 11793.66 (r/w/o: 7371.04/2948.42/1474.21) lat (ms,95%): 824.40 err/s: 0.00 reconn/s: 0.00
[   2s ] thds: 160 tps: 772.67 qps: 12362.70 (r/w/o: 7726.69/3090.68/1545.34) lat (ms,95%): 812.11 err/s: 0.00 reconn/s: 0.00
[   3s ] thds: 160 tps: 831.46 qps: 13303.43 (r/w/o: 8314.64/3325.86/1662.93) lat (ms,95%): 807.01 err/s: 0.00 reconn/s: 0.00
[   4s ] thds: 160 tps: 855.24 qps: 13683.77 (r/w/o: 8552.36/3420.94/1710.47) lat (ms,95%): 819.49 err/s: 0.00 reconn/s: 0.00
[   5s ] thds: 160 tps: 887.33 qps: 14197.31 (r/w/o: 8873.32/3549.33/1774.66) lat (ms,95%): 807.55 err/s: 0.00 reconn/s: 0.00
[   6s ] thds: 160 tps: 989.86 qps: 15837.68 (r/w/o: 9898.55/3959.42/1979.71) lat (ms,95%): 822.25 err/s: 0.00 reconn/s: 0.00
[   7s ] thds: 160 tps: 990.42 qps: 15846.73 (r/w/o: 9904.21/3961.68/1980.84) lat (ms,95%): 794.12 err/s: 0.00 reconn/s: 0.00
[   8s ] thds: 160 tps: 1061.96 qps: 16991.28 (r/w/o: 10619.55/4247.82/2123.91) lat (ms,95%): 814.02 err/s: 0.00 reconn/s: 0.00
[   9s ] thds: 160 tps: 1169.76 qps: 18716.18 (r/w/o: 11697.61/4679.04/2339.52) lat (ms,95%): 808.74 err/s: 0.00 reconn/s: 0.00
[  10s ] thds: 160 tps: 1206.91 qps: 19310.56 (r/w/o: 12069.10/4827.64/2413.82) lat (ms,95%): 781.97 err/s: 0.00 reconn/s: 0.00
[  11s ] thds: 160 tps: 1322.03 qps: 21152.40 (r/w/o: 13220.25/5288.10/2644.05) lat (ms,95%): 795.06 err/s: 0.00 reconn/s: 0.00
[  12s ] thds: 160 tps: 1392.36 qps: 22277.81 (r/w/o: 13923.63/5569.45/2784.73) lat (ms,95%): 799.34 err/s: 0.00 reconn/s: 0.00
[  13s ] thds: 160 tps: 1491.74 qps: 23867.81 (r/w/o: 14917.38/5966.95/2983.48) lat (ms,95%): 763.73 err/s: 0.00 reconn/s: 0.00
[  14s ] thds: 160 tps: 1611.73 qps: 25787.67 (r/w/o: 16117.29/6446.92/3223.46) lat (ms,95%): 767.41 err/s: 0.00 reconn/s: 0.00
[  15s ] thds: 160 tps: 1710.99 qps: 27375.84 (r/w/o: 17109.90/6843.96/3421.98) lat (ms,95%): 781.17 err/s: 0.00 reconn/s: 0.00
[  16s ] thds: 160 tps: 1777.08 qps: 28433.29 (r/w/o: 17770.81/7108.32/3554.16) lat (ms,95%): 749.54 err/s: 0.00 reconn/s: 0.00
[  17s ] thds: 160 tps: 1904.02 qps: 30464.26 (r/w/o: 19040.16/7616.07/3808.03) lat (ms,95%): 755.86 err/s: 0.00 reconn/s: 0.00
[  18s ] thds: 160 tps: 2065.56 qps: 33048.90 (r/w/o: 20655.56/8262.22/4131.11) lat (ms,95%): 749.80 err/s: 0.00 reconn/s: 0.00
[  19s ] thds: 160 tps: 2279.47 qps: 36471.54 (r/w/o: 22794.71/9117.88/4558.94) lat (ms,95%): 729.72 err/s: 0.00 reconn/s: 0.00
[  20s ] thds: 160 tps: 2437.89 qps: 39006.25 (r/w/o: 24378.91/9751.56/4875.78) lat (ms,95%): 722.73 err/s: 0.00 reconn/s: 0.00
[  21s ] thds: 160 tps: 2597.92 qps: 41566.77 (r/w/o: 25979.23/10391.69/5195.85) lat (ms,95%): 731.76 err/s: 0.00 reconn/s: 0.00
[  22s ] thds: 160 tps: 2852.57 qps: 45641.16 (r/w/o: 28525.72/11410.29/5705.14) lat (ms,95%): 698.27 err/s: 0.00 reconn/s: 0.00
[  23s ] thds: 160 tps: 2989.61 qps: 47833.79 (r/w/o: 29896.12/11958.45/5979.22) lat (ms,95%): 692.62 err/s: 0.00 reconn/s: 0.00
[  24s ] thds: 160 tps: 3130.54 qps: 50088.63 (r/w/o: 31305.39/12522.16/6261.08) lat (ms,95%): 694.57 err/s: 0.00 reconn/s: 0.00
[  25s ] thds: 160 tps: 3493.16 qps: 55890.61 (r/w/o: 34931.63/13972.65/6986.33) lat (ms,95%): 668.18 err/s: 0.00 reconn/s: 0.00
[  26s ] thds: 160 tps: 3771.42 qps: 60342.65 (r/w/o: 37714.16/15085.66/7542.83) lat (ms,95%): 662.67 err/s: 0.00 reconn/s: 0.00
[  27s ] thds: 160 tps: 3968.27 qps: 63492.33 (r/w/o: 39682.71/15873.08/7936.54) lat (ms,95%): 634.52 err/s: 0.00 reconn/s: 0.00
[  28s ] thds: 160 tps: 4159.66 qps: 66554.57 (r/w/o: 41596.61/16638.64/8319.32) lat (ms,95%): 642.03 err/s: 0.00 reconn/s: 0.00
[  29s ] thds: 160 tps: 4676.66 qps: 74826.57 (r/w/o: 46766.61/18706.64/9353.32) lat (ms,95%): 617.81 err/s: 0.00 reconn/s: 0.00
[  30s ] thds: 160 tps: 4975.73 qps: 79611.67 (r/w/o: 49757.30/19902.92/9951.46) lat (ms,95%): 602.27 err/s: 0.00 reconn/s: 0.00
[  31s ] thds: 160 tps: 5093.37 qps: 81493.95 (r/w/o: 50933.72/20373.49/10186.74) lat (ms,95%): 574.49 err/s: 0.00 reconn/s: 0.00
[  32s ] thds: 160 tps: 5477.72 qps: 87643.58 (r/w/o: 54777.24/21910.89/10955.45) lat (ms,95%): 574.42 err/s: 0.00 reconn/s: 0.00
[  33s ] thds: 160 tps: 5996.19 qps: 95938.99 (r/w/o: 59961.87/23984.75/11992.37) lat (ms,95%): 554.88 err/s: 0.00 reconn/s: 0.00
[  34s ] thds: 160 tps: 6401.78 qps: 102428.46 (r/w/o: 64017.79/25607.12/12803.56) lat (ms,95%): 521.90 err/s: 0.00 reconn/s: 0.00
[  35s ] thds: 160 tps: 6522.43 qps: 104358.88 (r/w/o: 65224.30/26089.72/13044.86) lat (ms,95%): 500.50 err/s: 0.00 reconn/s: 0.00
[  36s ] thds: 160 tps: 7117.04 qps: 113872.59 (r/w/o: 71170.37/28468.15/14234.07) lat (ms,95%): 496.24 err/s: 0.00 reconn/s: 0.00
[  37s ] thds: 160 tps: 7341.32 qps: 117461.05 (r/w/o: 73413.16/29365.26/14682.63) lat (ms,95%): 470.83 err/s: 0.00 reconn/s: 0.00
[  38s ] thds: 160 tps: 7609.25 qps: 121747.97 (r/w/o: 76092.48/30436.99/15218.50) lat (ms,95%): 455.90 err/s: 0.00 reconn/s: 0.00
[  39s ] thds: 160 tps: 8338.56 qps: 133416.92 (r/w/o: 83385.57/33354.23/16677.11) lat (ms,95%): 435.84 err/s: 0.00 reconn/s: 0.00
[  40s ] thds: 160 tps: 8709.51 qps: 139352.15 (r/w/o: 87095.09/34838.04/17419.02) lat (ms,95%): 413.40 err/s: 0.00 reconn/s: 0.00
[  41s ] thds: 160 tps: 8683.61 qps: 138937.69 (r/w/o: 86836.06/34734.42/17367.21) lat (ms,95%): 390.42 err/s: 0.00 reconn/s: 0.00
[  42s ] thds: 160 tps: 9229.41 qps: 147670.61 (r/w/o: 92294.13/36917.65/18458.83) lat (ms,95%): 372.85 err/s: 0.00 reconn/s: 0.00
[  43s ] thds: 160 tps: 9878.66 qps: 158058.49 (r/w/o: 98786.55/39514.62/19757.31) lat (ms,95%): 351.62 err/s: 0.00 reconn/s: 0.00
[  44s ] thds: 160 tps: 10262.83 qps: 164205.27 (r/w/o: 102628.30/41051.32/20525.66) lat (ms,95%): 323.95 err/s: 0.00 reconn/s: 0.00
[  45s ] thds: 160 tps: 10618.50 qps: 169896.01 (r/w/o: 106185.01/42474.00/21237.00) lat (ms,95%): 303.06 err/s: 0.00 reconn/s: 0.00
[  46s ] thds: 160 tps: 11032.84 qps: 176525.49 (r/w/o: 110328.43/44131.37/22065.69) lat (ms,95%): 293.45 err/s: 0.00 reconn/s: 0.00
[  47s ] thds: 160 tps: 10948.33 qps: 175173.35 (r/w/o: 109483.34/43793.34/21896.67) lat (ms,95%): 274.76 err/s: 0.00 reconn/s: 0.00
[  48s ] thds: 160 tps: 11435.82 qps: 182973.14 (r/w/o: 114358.21/45743.28/22871.64) lat (ms,95%): 252.03 err/s: 0.00 reconn/s: 0.00
[  49s ] thds: 160 tps: 11987.82 qps: 191805.18 (r/w/o: 119878.24/47951.30/23975.65) lat (ms,95%): 234.80 err/s: 0.00 reconn/s: 0.00
[  50s ] thds: 160 tps: 11735.70 qps: 187771.18 (r/w/o: 117356.99/46942.79/23471.40) lat (ms,95%): 218.80 err/s: 0.00 reconn/s: 0.00
[  51s ] thds: 160 tps: 12240.85 qps: 195853.53 (r/w/o: 122408.46/48963.38/24481.69) lat (ms,95%): 209.42 err/s: 0.00 reconn/s: 0.00
[  52s ] thds: 160 tps: 12994.85 qps: 207917.60 (r/w/o: 129948.50/51979.40/25989.70) lat (ms,95%): 190.38 err/s: 0.00 reconn/s: 0.00
[  53s ] thds: 160 tps: 13007.68 qps: 208122.90 (r/w/o: 130076.82/52030.73/26015.36) lat (ms,95%): 177.83 err/s: 0.00 reconn/s: 0.00
[  54s ] thds: 160 tps: 13520.02 qps: 216320.35 (r/w/o: 135200.22/54080.09/27040.04) lat (ms,95%): 166.03 err/s: 0.00 reconn/s: 0.00
[  55s ] thds: 160 tps: 13720.64 qps: 219530.22 (r/w/o: 137206.38/54882.55/27441.28) lat (ms,95%): 151.46 err/s: 0.00 reconn/s: 0.00
[  56s ] thds: 160 tps: 13964.78 qps: 223436.51 (r/w/o: 139647.82/55859.13/27929.56) lat (ms,95%): 140.78 err/s: 0.00 reconn/s: 0.00
[  57s ] thds: 160 tps: 14162.88 qps: 226606.06 (r/w/o: 141628.79/56651.52/28325.76) lat (ms,95%): 130.91 err/s: 0.00 reconn/s: 0.00
[  58s ] thds: 160 tps: 13637.61 qps: 218201.76 (r/w/o: 136376.10/54550.44/27275.22) lat (ms,95%): 122.09 err/s: 0.00 reconn/s: 0.00
[  59s ] thds: 160 tps: 14331.77 qps: 229308.30 (r/w/o: 143317.69/57327.08/28663.54) lat (ms,95%): 112.51 err/s: 0.00 reconn/s: 0.00
[  60s ] thds: 160 tps: 14388.60 qps: 230217.53 (r/w/o: 143885.95/57554.38/28777.19) lat (ms,95%): 105.01 err/s: 0.00 reconn/s: 0.00
[  61s ] thds: 160 tps: 14345.61 qps: 229529.79 (r/w/o: 143456.12/57382.45/28691.22) lat (ms,95%): 97.50 err/s: 0.00 reconn/s: 0.00
[  62s ] thds: 160 tps: 14366.84 qps: 229869.40 (r/w/o: 143668.37/57467.35/28733.67) lat (ms,95%): 90.78 err/s: 0.00 reconn/s: 0.00
[  63s ] thds: 160 tps: 14267.35 qps: 228277.62 (r/w/o: 142673.51/57069.40/28534.70) lat (ms,95%): 84.84 err/s: 0.00 reconn/s: 0.00
[  64s ] thds: 160 tps: 14856.89 qps: 237710.27 (r/w/o: 148568.92/59427.57/29713.78) lat (ms,95%): 78.02 err/s: 0.00 reconn/s: 0.00
[  65s ] thds: 160 tps: 15145.66 qps: 242330.59 (r/w/o: 151456.62/60582.65/30291.32) lat (ms,95%): 72.25 err/s: 0.00 reconn/s: 0.00
[  66s ] thds: 160 tps: 14904.02 qps: 238464.25 (r/w/o: 149040.16/59616.06/29808.03) lat (ms,95%): 65.48 err/s: 0.00 reconn/s: 0.00
[  67s ] thds: 160 tps: 15264.74 qps: 244235.80 (r/w/o: 152647.37/61058.95/30529.47) lat (ms,95%): 61.51 err/s: 0.00 reconn/s: 0.00
[  68s ] thds: 160 tps: 15027.90 qps: 240446.33 (r/w/o: 150278.96/60111.58/30055.79) lat (ms,95%): 58.43 err/s: 0.00 reconn/s: 0.00
[  69s ] thds: 160 tps: 15473.75 qps: 247579.95 (r/w/o: 154737.47/61894.99/30947.49) lat (ms,95%): 53.27 err/s: 0.00 reconn/s: 0.00
[  70s ] thds: 160 tps: 15165.17 qps: 242642.74 (r/w/o: 151651.71/60660.68/30330.34) lat (ms,95%): 49.92 err/s: 0.00 reconn/s: 0.00
[  71s ] thds: 160 tps: 15312.89 qps: 245006.26 (r/w/o: 153128.91/61251.56/30625.78) lat (ms,95%): 46.44 err/s: 0.00 reconn/s: 0.00
[  72s ] thds: 160 tps: 15114.26 qps: 241828.10 (r/w/o: 151142.56/60457.02/30228.51) lat (ms,95%): 43.69 err/s: 0.00 reconn/s: 0.00
[  73s ] thds: 160 tps: 15921.69 qps: 254746.98 (r/w/o: 159216.86/63686.75/31843.37) lat (ms,95%): 41.40 err/s: 0.00 reconn/s: 0.00
[  74s ] thds: 160 tps: 15935.10 qps: 254961.58 (r/w/o: 159350.99/63740.39/31870.20) lat (ms,95%): 38.80 err/s: 0.00 reconn/s: 0.00
[  75s ] thds: 160 tps: 15415.71 qps: 246651.43 (r/w/o: 154157.14/61662.86/30831.43) lat (ms,95%): 36.43 err/s: 0.00 reconn/s: 0.00
[  76s ] thds: 160 tps: 15172.30 qps: 242756.86 (r/w/o: 151723.04/60689.21/30344.61) lat (ms,95%): 34.01 err/s: 0.00 reconn/s: 0.00
[  77s ] thds: 160 tps: 15610.77 qps: 249772.32 (r/w/o: 156107.70/62443.08/31221.54) lat (ms,95%): 32.54 err/s: 0.00 reconn/s: 0.00
[  78s ] thds: 160 tps: 15854.85 qps: 253677.66 (r/w/o: 158548.53/63419.41/31709.71) lat (ms,95%): 30.69 err/s: 0.00 reconn/s: 0.00
[  79s ] thds: 160 tps: 15683.78 qps: 250940.48 (r/w/o: 156837.80/62735.12/31367.56) lat (ms,95%): 28.86 err/s: 0.00 reconn/s: 0.00
[  80s ] thds: 160 tps: 15739.70 qps: 251835.21 (r/w/o: 157397.01/62958.80/31479.40) lat (ms,95%): 28.24 err/s: 0.00 reconn/s: 0.00
[  81s ] thds: 160 tps: 16069.71 qps: 257115.41 (r/w/o: 160697.13/64278.85/32139.43) lat (ms,95%): 26.17 err/s: 0.00 reconn/s: 0.00
[  82s ] thds: 160 tps: 15417.35 qps: 246677.57 (r/w/o: 154173.48/61669.39/30834.70) lat (ms,95%): 25.38 err/s: 0.00 reconn/s: 0.00
[  83s ] thds: 160 tps: 15957.45 qps: 255319.23 (r/w/o: 159574.52/63829.81/31914.90) lat (ms,95%): 24.15 err/s: 0.00 reconn/s: 0.00
[  84s ] thds: 160 tps: 16152.06 qps: 258433.01 (r/w/o: 161520.63/64608.25/32304.13) lat (ms,95%): 23.60 err/s: 0.00 reconn/s: 0.00
[  85s ] thds: 160 tps: 16030.14 qps: 256482.31 (r/w/o: 160301.45/64120.58/32060.29) lat (ms,95%): 22.25 err/s: 0.00 reconn/s: 0.00
[  86s ] thds: 160 tps: 15593.84 qps: 249501.47 (r/w/o: 155938.42/62375.37/31187.68) lat (ms,95%): 21.31 err/s: 0.00 reconn/s: 0.00
[  87s ] thds: 160 tps: 15650.67 qps: 250410.70 (r/w/o: 156506.69/62602.67/31301.34) lat (ms,95%): 20.99 err/s: 0.00 reconn/s: 0.00

前往PolarDB控制台，在效能監控頁面查看Serverless监控指标项。根據測試時間調整時間範圍，可以看到如下監控資訊：

在Serverless監控資訊中，會觀察到新的唯讀節點的負載曲線。當唯讀節點被彈出後，先前的節點負載將逐步降低，最終達到一個大致的均衡狀態。
運行一段時間後，停止壓測。根據測試時間調整時間範圍，可以看到如下監控資訊：

叢集的計算節點首先會自動進行縮容，大約2～3分鐘會逐步降至1 PCU。當壓力停止後，唯讀節點的CPU使用率會立刻降低，而主節點還需要執行vacuum 操作，CPU消耗會持續一小段時間，最終降到1 PCU。

之後等待較長一段時間，新增的唯讀節點也會在15～20分鐘內逐步回收。為了避免唯讀節點頻繁的彈性震蕩，Serverless沒有選擇立即回收無負載的唯讀節點。