Re: Dangling Client Backend Process
От | Rajeev rastogi |
---|---|
Тема | Re: Dangling Client Backend Process |
Дата | |
Msg-id | BF2827DCCE55594C8D7A8F7FFD3AB771599653F7@szxeml521-mbs.china.huawei.com обсуждение исходный текст |
Ответ на | Re: Dangling Client Backend Process (Amit Kapila <amit.kapila16@gmail.com>) |
Список | pgsql-hackers |
<div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">On</span><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">10October 2015 20:45, Amit Kapila Wrote:</span><p class="MsoNormal"><spanstyle="font-size:10.0pt;font-family:"Tahoma","sans-serif""> </span><p class="MsoNormal"><span style="font-size:13.0pt">>>I observed one strange behavior today that if postmaster process gets crashed/killed, thenit kill all background processes but not the client backend process.</span><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><pclass="MsoNormal">> This is a knownbehaviour and there was some discussion on this<p class="MsoNormal">> topic [1] previously as well. I think thatthread didn't reach to conclusion,<p class="MsoNormal">> but there were couple of other reasons discussed in thatthread as well to<p class="MsoNormal">> have the behaviour as you are proposing here.<p class="MsoNormal"> <p class="MsoNormal"><spanstyle="font-size:13.0pt">Oops..I did not know about this. I shall check the older thread to get otheropinions.</span><p class="MsoNormal"> <p class="MsoNormal"><span style="font-size:13.0pt">>> One way to handlethis issue will be to check whether postmaster is alive after every command read but it will add extra cost for eachquery execution.</span><p class="MsoNormal"><span style="font-size:13.0pt"> </span><p class="MsoNormal">> I don'tthink that is a good idea as if there is no command execution<p class="MsoNormal">> it will still stay as it is anddoing such operations on each command<p class="MsoNormal">> doesn't sound to be good idea even though overhead mightnot be<p class="MsoNormal">> big. There are some other ideas discussed in that thread [2] to achieve<p class="MsoNormal">>this behaviour, but I think we need to find a portable way to achieve it.<p class="MsoNormal"><spanstyle="font-size:13.0pt"> </span><p class="MsoNormal"><span style="font-size:13.0pt">Yes, you areright that process will not be closed till a new command comes but I think it does not harm functionality in anyway exceptthat the process and its acquired resources</span><p class="MsoNormal"><span style="font-size:13.0pt">does not getfreed. Also use-case of application will be very less where their client process stays idle for very long time.</span><pclass="MsoNormal"><span style="font-size:13.0pt">But at the same time I agree this is not the best solution,we should look for more appropriate/better one. </span><p class="MsoNormal"><span style="font-size:13.0pt">Now asit is confirmed to be valid issue, I will spend some time on this to find if there is something more appropriate solution.</span><pclass="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><pclass="MsoNormal"><i><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black">Thanksand Regards,</span></i><p class="MsoNormal"><i><spanstyle="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Kumar Rajeev Rastogi</span></i><i><spanstyle="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black"> </span></i></div>
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