<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Verdana;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
span.apple-converted-space
{mso-style-name:apple-converted-space;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span lang=EN-US>Hi all,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>We’re facing a situation that would like some expertise to be solved.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>First of all, our setup consists of 3 databases Postgres 9.1, PGPool 3.2 STABLE checked out from the repository (rev </span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>6dde744) and PGPoolAdmin 3.2.0.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>We have setup replication and load balancing, along with scripts for online recovery.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>The cluster works fine in terms of replicating and load balancing data.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>But, the servers host other applications expect of the databases.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>Some applications require a lot of CPU when running.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>We found recently that when CPU is high in a backend, PGPool fails to update the data on this server and that causes a ‘</span><span style='font-size:9.0pt;font-family:"Courier New"'>kind mismatch among backends’ </span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>situation.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>I know that there is a </span><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black;background:white'>replication_stop_on_mismatch<span class=apple-converted-space> parameter in pgpool conf, but that will disconnect the database from the cluster and we will have to re-attach it (this could happen several times)</span></span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>.</span><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:black;background:white'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>So I was wondering, if there is a more permanent workaround for this. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>Is it something we can configure in PGPool?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>Are there any minimum memory requirements that we could set to avoid this problem?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>Would that be in Postgres?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>Maybe the best option is to dedicate the server to run the database only (?).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>Thanks in advance for your help and your time.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>Regards,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif";mso-fareast-language:EN-GB'>Stelios<o:p></o:p></span></p></div></body></html>