<html><head></head><body><div style="color:black;font-size:14px">Hello.<br></div><div style="color: black;font-size: 14px;">We are having quite frequent crashes of our pdns server with the following syslog messages:<br></div><div style="color: black;font-size: 14px;"><br></div><blockquote style="border-left: 2px solid rgb(168, 168, 168); padding-left: 10px; margin-top: 0.5rem; margin-block-start: 0px; margin-inline-start: 0px;"><div style="color: black;font-size: 14px;">Feb 17 13:39:33 xxxx.xxxxx.xxx.xxxx pdns_server[26672]: Exiting because communicator thread died with error: GSQLBackend unable to refresh domain_id XXXXX: Could not execute mysql statement: update domains set notified_serial=? where id=?: Deadlock found when trying to get lock; try restarting transaction<br></div><div style="color: black;font-size: 14px;">Feb 17 13:39:34 xxxx.xxxxx.xxx.xxxx systemd[1]: pdns.service: main process exited, code=exited, status=1/FAILURE</div><div style="color: black;font-size: 14px;">Feb 17 13:39:34 xxxx.xxxxx.xxx.xxxx systemd[1]: Unit pdns.service entered failed state.</div><div style="color: black;font-size: 14px;">Feb 17 13:39:34 xxxx.xxxxx.xxx.xxxx systemd[1]: pdns.service failed.</div><div style="color: black;font-size: 14px;">Feb 17 13:39:35 xxxx.xxxxx.xxx.xxxx systemd[1]: pdns.service holdoff time over, scheduling restart.</div><div style="color: black;font-size: 14px;">Feb 17 13:39:35 xxxx.xxxxx.xxx.xxxx systemd[1]: Stopped PowerDNS Authoritative Server.</div><div style="color: black;font-size: 14px;">Feb 17 13:39:35 xxxx.xxxxx.xxx.xxxx systemd[1]: Starting PowerDNS Authoritative Server...</div><div style="color: black;font-size: 14px;">Feb 17 13:39:35 xxxx.xxxxx.xxx.xxxx pdns_server[25899]: Loading '/usr/lib64/pdns/libgmysqlbackend.so'</div><div style="color: black;font-size: 14px;">Feb 17 13:39:35 xxxx.xxxxx.xxx.xxxx pdns_server[25899]: This is a standalone pdns</div><div style="color: black;font-size: 14px;"><br></div></blockquote><div style="color:black;font-size:14px">I don't know if this can be related, but just before those crashes we see messages like:<br></div><div style="color: black;font-size: 14px;"><br></div><blockquote style="border-left: 2px solid rgb(168, 168, 168); padding-left: 10px; margin-top: 0.5rem; margin-block-start: 0px; margin-inline-start: 0px;"><div style="color: black;font-size: 14px;">Feb 17 13:39:32 xxxx.xxxxx.xxx.xxxx pdns_server[26672]: Request to queue notification for domain yyyyy.yy was processed, but no valid nameserver or ALSO-NOTIFYs found. Not notifying!</div><div style="color: black;font-size: 14px;"><br></div></blockquote><div style="color:black;font-size:14px" class="signature">Just to mention briefly our setup: we are running:<br></div><div style="color: black;font-size: 14px;">PowerDNS Authoritative Server 4.5.2 (C)<br></div><div style="color: black;font-size: 14px;"><br></div><div style="color: black;font-size: 14px;">in a percona mysql cluster with three nodes, each node having it's own mysql and pdns server (in order to have redundancy of database and APIs).<br></div><div style="color: black;font-size: 14px;"><br></div><div style="color: black;font-size: 14px;">This cluster acts as a "backend master" for the real authoritative slaves, placed elsewhere, replicating the db.<br></div><div style="color: black;font-size: 14px;"><br></div><div style="color: black;font-size: 14px;">Can you help us to understand why we have those crashes?<br></div><div style="color: black;font-size: 14px;"><br></div><div style="color: black;font-size: 14px;">Thanks<br></div><div style="color: black;font-size: 14px;">Riccardo</div><div style="color: black;font-size: 14px;"> <br></div></body></html>