Thanks a lot to all of you for your valuable hints. So I tried some more
and found that traceroute and ping show the same symptoms, i.e. first
call takes 5 seconds. However, traceroute -4 and ping -4 always respond
immediately.
So, searching for "linux dns lookup takes long ipv4" brought me to https://askubuntu.com/a/32312 on AskUbuntu that suggested addingSo, according to the page linked there, I'm maybe having to do with a DNS Server or Firewall that doesn't handle the parallel IPv4 and IPv6 requests properly... I'll check with my IT.
On 31 May 2018 at 16:54, Achilleas Mantzios <achill@xxxxxxxxxxxxxxxxxxxxx> wrote:
On 28/05/2018 17:26, Andreas Schmid wrote:
IPv4 vs IPv6 ? any strange timeouts? look in the postgresql logs for any messages.Does anyone of you have an explanation for this, or a hint, where I could do some further investigation?both always returned the host name and IP address of the LDAP server immediately.host my.ldap.server.orgWhen I checked on the DB machine with the following commandsThe LDAP server is behind a firewall. So for a test, in pg_hba.conf I put the LDAP servers IP address instead of its DNS name (for parameter ldapserver). Like that, all logins complete immediately. But in general I prefer specifying the DNS name rather than the IP.Hi,I configured my PostgreSQL 10 DB on Debian 9.2 with LDAP authentication (simple bind mode). While this basically works, it has the strange effect that the first login with psql takes around 5 seconds. When I reconnect within 60 seconds, the login completes immediately.
Also definitely ran wireshark, it'll tell you a lot on what's happening between postgresql and your LDAP .AndyThanks,
-- Achilleas Mantzios IT DEV Lead IT DEPT Dynacom Tankers Mgmt
