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Hostname verification backoff schedule

Attempts to verify a Custom Hostname are distributed over 7 days (a total of 75 retries). The function that determines the next check varies based on the number of attempts:

  • For the first 10 attempts:
now() + min((floor(60 * pow(1.05, retry_attempt)) * INTERVAL '1 second'), INTERVAL '4 hours')
  • For the remaining 65 attempts:
now() + min((floor(60 * pow(1.15, retry_attempt)) * INTERVAL '1 second'), INTERVAL '4 hours')

The first 10 checks complete within 2 minutes and most checks complete in the first 4 hours. The check back off is capped to a maximum of 4 hours to avoid exponential growth. The back off behavior causes larger gaps between check intervals towards the end of the back off schedule:

Retry Attempt In Seconds In Minutes In Hours
0 60 1 0.016667
1 63 1.05 0.0175
2 66 1.1 0.018333
3 69 1.15 0.019167
4 72 1.2 0.02
5 76 1.266667 0.021111
6 80 1.333333 0.022222
7 84 1.4 0.023333
8 88 1.466667 0.024444
9 93 1.55 0.025833
10 242 4.033333 0.067222
11 279 4.65 0.0775
12 321 5.35 0.089167
13 369 6.15 0.1025
14 424 7.066667 0.117778
15 488 8.133333 0.135556
16 561 9.35 0.155833
17 645 10.75 0.179167
18 742 12.366667 0.206111
19 853 14.216667 0.236944
20 981 16.35 0.2725
21 1129 18.816667 0.313611
22 1298 21.633333 0.360556
23 1493 24.883333 0.414722
24 1717 28.616667 0.476944
25 1975 32.916667 0.548611
26 2271 37.85 0.630833
27 2612 43.533333 0.725556
28 3003 50.05 0.834167
29 3454 57.566667 0.959444
30 3972 66.2 1.103333
31 4568 76.133333 1.268889
32 5253 87.55 1.459167
33 6041 100.683333 1.678056
34 6948 115.8 1.93
35 7990 133.166667 2.219444
36 9189 153.15 2.5525
37 10567 176.116667 2.935278
38 12152 202.533333 3.375556
39 13975 232.916667 3.881944
40 14400 240 4
41 14400 240 4
42 14400 240 4
43 14400 240 4
44 14400 240 4
45 14400 240 4
46 14400 240 4
47 14400 240 4
48 14400 240 4
49 14400 240 4
50 14400 240 4
51 14400 240 4
52 14400 240 4
53 14400 240 4
54 14400 240 4
55 14400 240 4
56 14400 240 4
57 14400 240 4
58 14400 240 4
59 14400 240 4
60 14400 240 4
61 14400 240 4
62 14400 240 4
63 14400 240 4
64 14400 240 4
65 14400 240 4
66 14400 240 4
67 14400 240 4
68 14400 240 4
69 14400 240 4
70 14400 240 4
71 14400 240 4
72 14400 240 4
73 14400 240 4
74 14400 240 4
75 14400 240 4