Behavior difference for walsender and walreceiver for n/w breakdown case
От | Amit Kapila |
---|---|
Тема | Behavior difference for walsender and walreceiver for n/w breakdown case |
Дата | |
Msg-id | 005d01cd8bf6$206ea430$614bec90$@kapila@huawei.com обсуждение исходный текст |
Список | pgsql-hackers |
<div class="WordSection1"><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">I have observedthat currently incase there is a network break between master and standby, walsender process gets terminated immediately,however</span><br /><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">walreceiver detects the breakageafter long time. </span><br /><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">The main reason I couldsee is due to replication_timeout configuration parameter, walsender checks for replication_timeout, if there is nocommunication from other side till replication_timeout time it detects it as a condition to terminate the walsender. </span><br/><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">However there is no such mechanism in walreceiver,it fails during send socket call from XLogWalRcvSendReply() after calling the same many times as internally mightbe in send until the sockets internal buffer is full, it keeps accumulating even if other side recv has not receivedthe data.</span><br /><br /><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Shouldn't in walreceiver,there be a mechanism so that it can detect n/w failure sooner</span>?<br /><br /><br /><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">BasicSteps to observe above behavior</span><br /><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">1.Both master and standby machine are connected normally, <br />2.then you use the command: ifconfig ip down; make the network card of master and standby down, <br />Observation <br />mastercan detect connect abnormal, but the standby can't detect connect abnormal and show a connected channel long time.<br /><br />With Regards,</span><br /><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Amit Kapila</span></div>
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