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<p>Hello.</p>
<p>I red this article about health_check_* options:
<a class="moz-txt-link-freetext" href="http://pgsqlpgpool.blogspot.com/2013/09/health-check-parameters.html">http://pgsqlpgpool.blogspot.com/2013/09/health-check-parameters.html</a>
and i liitle confised, because author of article was wrote, that:</p>
<p>
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Please note that "health_check_max_retries *
(health_check_timeout+health_check_retry_delay)" should be smaller
than health_check_period.</p>
<p>In can't find about it in official pgpool documentation. It is
really required?</p>
<p><br>
</p>
<p>And second question. I'm testing those options on Google Cloud
servers, with the following options:</p>
<p>health_check_period = 60<br>
health_check_timeout = 10<br>
health_check_max_retries = 3<br>
health_check_retry_delay = 7</p>
<p>(health_check_period=60 because of above article). I use also
repmgr with connect_timeout=10s, so whole time switch is about 2
minutes, i.e. (time: mm:ss):<br>
</p>
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39:03 - master node goes down<br style="color: rgb(51, 51, 51);
font-family: Arial, sans-serif; font-size: 14px; font-style:
normal; font-variant: normal; font-weight: normal;
letter-spacing: normal; line-height: 20px; orphans: auto;
text-align: start; text-indent: 0px; text-transform: none;
white-space: normal; widows: 1; word-spacing: 0px;
-webkit-text-stroke-width: 0px; background-color: rgb(245, 245,
245);">
39:51 - pgpool see, that is problem to connect<br style="color:
rgb(51, 51, 51); font-family: Arial, sans-serif; font-size:
14px; font-style: normal; font-variant: normal; font-weight:
normal; letter-spacing: normal; line-height: 20px; orphans:
auto; text-align: start; text-indent: 0px; text-transform: none;
white-space: normal; widows: 1; word-spacing: 0px;
-webkit-text-stroke-width: 0px; background-color: rgb(245, 245,
245);">
40:08 - failed mode, retry 1<br style="color: rgb(51, 51, 51);
font-family: Arial, sans-serif; font-size: 14px; font-style:
normal; font-variant: normal; font-weight: normal;
letter-spacing: normal; line-height: 20px; orphans: auto;
text-align: start; text-indent: 0px; text-transform: none;
white-space: normal; widows: 1; word-spacing: 0px;
-webkit-text-stroke-width: 0px; background-color: rgb(245, 245,
245);">
40:25 - retry 2 (time between retry 1 and retry 2: 10 sec for
connect timeout and 7 second for delay for next retry)<br
style="color: rgb(51, 51, 51); font-family: Arial, sans-serif;
font-size: 14px; font-style: normal; font-variant: normal;
font-weight: normal; letter-spacing: normal; line-height: 20px;
orphans: auto; text-align: start; text-indent: 0px;
text-transform: none; white-space: normal; widows: 1;
word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(245, 245, 245);">
40:42 - retry 3<br style="color: rgb(51, 51, 51); font-family:
Arial, sans-serif; font-size: 14px; font-style: normal;
font-variant: normal; font-weight: normal; letter-spacing:
normal; line-height: 20px; orphans: auto; text-align: start;
text-indent: 0px; text-transform: none; white-space: normal;
widows: 1; word-spacing: 0px; -webkit-text-stroke-width: 0px;
background-color: rgb(245, 245, 245);">
40:52 - pgpool mark node as a down, and run failover script (10s
timeout after retry 3)<br style="color: rgb(51, 51, 51);
font-family: Arial, sans-serif; font-size: 14px; font-style:
normal; font-variant: normal; font-weight: normal;
letter-spacing: normal; line-height: 20px; orphans: auto;
text-align: start; text-indent: 0px; text-transform: none;
white-space: normal; widows: 1; word-spacing: 0px;
-webkit-text-stroke-width: 0px; background-color: rgb(245, 245,
245);">
41:02 - promoting slave as a master through repmgr (repmgr
checking, that old master really not working, so next 10s, because
of timeout)</p>
<p><br>
</p>
<p>I use health_check_retry_delay = 7 for situation, when i.e.
postgresql instance not works but server works, so any attepmt to
connect are immediately rejected, so timeout is very short, and
time for failover is also very short.</p>
<p>So I'm thinking about shorter time health_check_period and also
connect timeout. I set 10s, but what do you think, what value will
be good in cloud services (AWS, Google Cloud etc). Load on
postgres servers is low/medium.</p>
<pre wrap="">Best regards,
Kris
</pre>
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