Some time ago I’ve tried to solve a ‘funny’ issue with PowerDNS. It refused to start on one of my backup VPS. After apt-get dist-upgrade, it first stopped to work with very meaningful ‘
Failed at step ADDRESS_FAMILIES‘ error. Well, I’ve managed to solve it somehow, but than another ‘funny’ problem popped out…
Some hopefully useful tips on speeding up data import via SOLR DataImportHandler.
In PostgreSQL it’s quite easy to restrict access for user to some tables:
- create restrictive view
- grant usage on view schema
- grant select on view to restricted user
Really easy. And it’s not working when the restrictive view, is selecting from another view that is using function(s) ! In that case, you might get very informative error:
ERROR: permission denied for relation <TABLE>
ERROR: permission denied for schema <SCHEMA>
Why ? Well everything works as expected, you have permission to SELECT from that restrictive VIEW and thus you really have some access to the underlying view/table, but function used in that view is still executed with permission of restricted user and therefore you obviously end up with ‘permission denied‘.
Solution for this is simple, force affected function(s) to execute with privileges of user that created it:
ALTER FUNCTION <FUNCTION> SECURITY DEFINER;
See CREATE FUNCTION manual for more info.
I encountered this problem again, so let’s write it down to avoid googling it.
PowerDNS fails to start with
pdns.service: Failed at step ADDRESS_FAMILIES spawning /usr/sbin/pdns_server: Invalid argument
- edit /lib/systemd/system/pdns.service
- comment out RestrictAddressFamilies
- comment out ProtectSystem=full
- possibly kill systemd-resolved
- systemctl daemon-reload
- ask yourself again, why are you using debian with systemd on server ? And why the hell it is starting services I’ve never configured to start ? Isn’t it time to switch to windows ? It seems more predictable to me…
I’ve hacked together and up-to-date version of Asuswrt Merlin firmware for oldie but goldie Asus RT-N16 router. Beware, this firmware is only intended for use by advanced users.